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196 Cards in this Set
- Front
- Back
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What is the human genome project and in what year did it start?
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it was a goal to sequence the whole genome of man, using the genomes of anonymous donors and started in 1990
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How did Celera complete the human genome project?
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using robotic DNA sequences, they fragmented the genome & sequenced the pieces, then used computers to overlap the pieces to generate a map, much quicker, but possibly less accurate
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Who's genome was used in Celera,s human genome project?
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Craig Venter the president of the company
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What did Celera do with the pieces of the human genome they decoded?
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the pieces were patented even though Celera didnt know the functions(if any) of the individual pieces
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What year did Celera finish its HUman genome project?
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2000
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When did Celera publish its highly accurate human genome?
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spring 2003
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What is Celera busy with today?
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sequence annotation and discovery of new products, new technologies that involves methods for mining the huge amounts of data geerated by the projects. sequencing other model or pathogenic organisms.
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What organisms have their genome recorded and what year?
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arabidopsis in 2001, rice in 2002, Pinot noir grape in 2007, pig in 10/2009
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what had to be done in olden days to find a gene or other sequence?
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making a DNA library with a DNA probe, probe is a short sequence of DNA that is "unique" to that gene or other DNA segment.sometimes you have a good probe or not so good(i.e. specific or not) done by analysis of the clones in a DNA library, could take up to 2 years.
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Name of a popular search engine NIH?
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entrez
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Genbank is a searchable database of?
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genomes, chromosomes, cloned pieces of DNA , viruses, plasmids , tRNA's , rRNA's , mRNA's cDNA's, Expressed sequence tags, proteins and lots more
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comparative genomics?
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compares the genomes of many different organisms, looking for the similarities and differences to find information on evolution.
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what does comparative genetics require?
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the sequencing of the human genome and genomes of many other organisms, mostly confirms what we know about living things
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what are huge databases computer required to do with comparative genomics?
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store the sequence information search the sequence information compare the sequence information in a variety of ways. a tree of life can be generated from generic information
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pharmacogenomics define?
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analyze genes and proteins to identify targets for therapeutic drugs
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computational genomics?
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determine 3D structures of proteins (this information is also computer generated and manipulated)
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are genes with similar functions grouped?
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sometimes, often depends of whether the genes has the same evolutionary origins or not. Many genes for the different types of Hemoglobin are grouped in the human genome on particular chromosomes.
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Have we been able to map human chromosomes?
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Yes, but not yet finished.
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Are genes that are used in the same metabolic pathway or developmental pathway grouped?
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commonly but not always, for the same reasons as that we find genes are often linked(i.e if they are homologous they usually are linked)
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Are genes that are used in a metabolic pathway or developmental pathway coordinately controlled?
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many are(organized as a gene family), as this makes regulation more efficient
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can genes on different chromosomes be coordinately controlled?
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yes
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have biologists been able to assign functions to all the genes in the human genome?
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more less it is completed.
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Are all genomes similar in terms of size?
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no
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Size of genome: Homo sapiens (man)
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3.2 billion bases
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Size of genome: Drosophila melanogaster (fruit fly)
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165 million bases
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Size of genome: Saccharyomyces cerevisiae(brewer's yeast)?
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12 million bases
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Size of genome: Escherichia Coli(gut bacteria)
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4.6 million bases
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Are genomes similar in terms of organization?
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organisms that are closely related tend to have genomes that are organized similarly. Organisms that are not closely related have genomes that are organized differently(e.g. humans and turnicates have most of the same genes but they are in a completely different order)
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How conserved are genomes?
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In general, the more closely related, the more
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do more complex organisms have more complex genomes than the simpler organisms>
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yes
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how different at the D NA level must an organism be to be a different species?
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it varies a lot. up to 25% difference in organisms called E-coli. . difference between man and chimp is 0.5 to 2%. has to do with a non-uniform definition of species between kingdoms.
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Will comparisons of DNA differences in species tell us anything?`
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yes cladistics is based on this, tells a lot about mans origins
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repetitive DNA?
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DNA sequences that are repeated over and over at a locus in a chromosome is called Repetitive DNA
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What are short sequences of DNA that are exact copies called?
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tandem repeats, satellite DNA or simple sequence DNA. often found on telomeres or centromeres, indicates that tandem repeats have some function
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interspersed DNA?
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DNA sequences that are repeated over and over at several loci in a chromosome(longer sequences, usually not exact copies but close) are called interspersed repetitive DNA
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Do DNA sequences map to anything significant?
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not all of it, but tandem repeats do.
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where are tandem repeats foun at?
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telomeres of chromosomes and has a normal function in chromosomes replication. during each division tandem repeats are lost. when almost of the repeats are lost, that seems to be a signal for apoptosis, old mistake-laden cells are eliminated this way
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how has artificial chromosomes come about?
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cloning of tandem repeats/satellite DNA
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what is huntingtons disease at the DNA level?
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it is a triple repeat disease with many extra CAG's this leads to extra glutamines being added toa neurological protein which causes a nervous dysfunction and is 100% fatal.
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E-COLI stats?
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6mbp ,little repetitive DNA, 1 copy of DNA, has multigene families, haploid, 1 chromosome, no introns, no RNA processing, transposons 4100 genes, almost all the way coded
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Arabadopsis stats?
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100mbp, moderate to lots of repitive DNA, many copies of genes, has multigene families variable amts of isoforms, diploid, 4 chromosomes,has introns, does RNA processing, has transposons, 26K genes, 15k unique genes, DNA coding is widely varied
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Homosapiens?
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3.2bbp, lots of repetitive DNA, usually many # of copies , many isoforms of multigene families, diploid, 46 # of chromosomes and introns and RNA processing, has transposons humans have 45% transposons, 22,000 estimated # of genes, about 1.5% DNA completed
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What does C.elegans have in common with humans?
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it has 22k genes, but only 500 cells total, due to the size of mans interactome the human is larger
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what is an interactome?
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is the sum of all the proteins that interact(i.e. has some sort of regulatory effect) with each other. Man most likely has more translational variants of common proteins than the worm, larger interactome.
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Human size #exons, %introns, repeat %, transpersed, tandems, unique coding?
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3.2bbp, 1.5% coding exons:22k genes 25% introns regulatory sequences.25-45% interspersed repeats transposons & retrovirus footprints.10-15% tandem repeats, large segmantrepeats.15% Unique sequence but non-coding DNA(ex. microRNA, small interfering RNA)
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What is sometimes called selfish DNA?
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interspersed repeats transposons & retrovirus footprints because it doesnt seem to do anything, but is retained and has expanded itself. seems to be no burden of carrying extra DNA in man and therfore no selection against it.
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Junk DNA?
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75% of human genome is what used to be called JUNK DNA. many RNA were obviously at one time functional,probably part of the 15% unique, noncoding DNA. many footprints of transposons(very possibly the tandem repeats are these) lots of footprints of non-functional retroviruses(great way to follow evolution)genes for SiRNA and miRNA codes and other regulatory RNA's
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what doesnt code forprotein inthe human genome?
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miRNA ans siRNA coding DNA accounts for much of DNA that doesnt code for protein.
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Hypothesize about human genes and the CNS, as well as difference between humans and primates.
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researchers have hypothesized that the 22,000 genes of the human genome would not be able to account for the complexity of the human CNS. They have further hypothesized that the difference between man and other primates is not in the genes but in fine tuning of regulation of the same genes by siRNA and miRNA’s, variable splicing of exons during RNA processing and translation variants
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pseudogenes?
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pseudogenes extra copies of genes but are non-functional or marginally functional, psuedogenes are probably generated by gene amplification or transposons
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psuedogenes advantages?
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presence may allow for the incremental mutation of functional or non-functional genes into new genes.psuedogenes could act as back up genes that could take the place of a mutated primary gene. with backup genes, safer and therefore more rapid evolution can occur.
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transposons info?
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genetic elements that copy themselves and insert themselves into random places in the genome. insertions can add a functionality or destroy a functionality. discovered by Barbera McClintock (Nobel priza 1980)
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what is sectoring?
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anexample of transposons making a phenotypic change by adding a functionality
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Retrovirus footprints info?
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retroviruses have RNA genomes that undergo reverse transcription to DNA,the DNA than insertsinto the genome, sometimes the retrovirus becomes mutated and is no longer functional=retrovirus footprint
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plt genomes sequenced already?
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1st plt genome sequenced was in 2000:Arabidopsis thaliana, rice in 2002 then wheat corn tomato Pinotnoir grape recently
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plt genomes ploidy?
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aneuploidy is common (2n+1) and polyploidy(6n) genome size varies immensely due to polyploidy (from fewer than 4 chromosomes to over 1000 chromosomes in some ferns, leading to a huge genome)
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what % of a plt genome is transposons?
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90%
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how did some plt genomes expand in size?
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transposons
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chloroplast role in plt genome?
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many of the chloroplast genes have been transferredto the nuclear genome, therefore many of the chloroplast proteins that are made in the cytoplasm must be moved to chloroplast. similar story with mitochondria and most eukaryotes
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What does DNA circles do for plt genomes??
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incoporation of DNA circles certain cells during development make many copies of DNA circles with rRNA/tRNA genes. DNA circles are necessary for rapid expression during devel.(like having transient plasmids). rare mistakes are made and recombination with a chromosome occurs.
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gene amplification?
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expansion of human globin genes probably occurred through replication mistakes that lead to duplications, this is a type of event called gene amplification. globin genes in mammals likely expanded from a single ancestral gene be gene amplification.
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what has changed on the view of the genome over the years?
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old view was that the genome was relatively static, that view has changed, now know that these mechanisms for genome change occur commonly, they can drastically change a genome over a period of evolutionary time.
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ultimate goal of a plt molecular biologists?
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Discover the function of all genes in Arabadopsis. Then discover when and where these genes are expressed in the plt. With this info in hand, we will have an understanding of plt development at genetic level. Next, write a computer program to make a "virtual plt".Scientists be able to experiment on this virtual plt without having to dothe lab work.
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CAn the plt genome info be abused?
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yes insurance/employment discrimination, unauthorized experimentation, use of someone elses data, human cloning, use of someones cells to develop therapies
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how does a plt react to environmental cues?
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through evolution, growth difference,change developmental processes(make roots or leaves), change physiological processes(CAM responds to day vs night)
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what controls developmental and physiological responses?
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hormones, hormones are chemicals produced in one part of the body and affects another part of the body.actions are specific and they affect specific tissues.active in minute concentrations
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D&D findings about a coleoptile?
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grows straight up in normal overhead light and in the dark coleoptile grows towards light when the light comes from the side, however decapitated seedlings grow straight up in normal light, dark and side light.The tip is required for the response
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what results when D&D coveredbut intact seedling apex?
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growth straight up in normal light, side light and in the dark, deduced tip must sense the light for the response.in seedling with the apex covered with a transparent cap the seedlings grow straight up in normal light and in dark, but bend at base towards side lighting. deduced apex must somehow signal the plt to grow towards the light
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what happened when D&D covered the seedlings bases?
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they found that seedlings grow straight up in normal light and dark, but bend towards side lighting. confirming that tip and not the base must sense the light for the response, others determined later that cells elongate on the side away from the light and stay same length on side towards the light therefore allows the plant to grow towards light.
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Boysen and Jenson what year did they do their experiment?
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1913
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What year did D&D do their experiment?
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1880
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What did Boysen and Jenson find out?
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they guessed that the signal that was causing D&Ds results was a diffusible chemical produced at apex. They placed a gelatin block between apex and base, shoot grew straight up in normal light and in dark, but grew towards side light. deduced: apex sent chemical signal to base, and the chem diffused through gelatin.
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What did the mica prove in the Boysen Jenson experiment?
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when the gelatin was replced with mica the response was no response to light, deduced apex must send chemical signal to the base to have response(and in this case the mica blocked the diffusion)
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What year did Wendt do his experiment?
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1926
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What did Went do?
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he infused a gelatin block with putative"hormone" then he cut off the apex and replaced it with the "hormone" impregnated gelatin block between the shoot base and apex. light responses. no apex & block with no "hormone":no response to light(control).coleoptile with hormone gel block, no apex & normal light: grew straight(normal)(control)
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What happened when Went placed a block on the decapitated shoot with "hormone" offset(i.e. to the side)
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a seedling grows away from block(i.e. the "hormone") this is a normal response to light deduced: the "hormone" without light can induce cell response
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what did went propose after his experiment?
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he proposed that what was causing the effect was a light induced hormone, he called his proposed hormone auxin, the 1st plt hormone discovered. he proposed that auxin induces cell elongation. Needed 3 grps of investigators and 46yrs to demonstrate that a diffusible chemical controlled phototropism in plts. Auxin was later found to only one of several plt hormones that have varied functions in plts.
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Main plt hormones.
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gibberelin, ABA, Cytokinin, Auxin
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functional characteristics of the known plts hormones?
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effects induce or inhibit growth or short term effects. some hormones oppose each other like auxin (apical dominance in shoots) vs. cytokinins(promotes branching)places of action are where tissues grow or differentiate and other places where short term effects are seen
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Auxin background info?
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Found in the embryo of seed,meristems of apical buds,young leaves. stimulates stem elongation(low conc. only)root growth, cell differentiation, and branching:regulates development of fruit:enhances apical dominance:functions in phototropism and gravitropism:promotes xylem differentiation:retards leaf abscission
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Cytokinin background info?
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synthesized in roots and transported to other organs.Affect root growth and differentiation:stimulate cell division and growth;stimulate germination;delay senescence
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Gibberellins background info?
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meristems of apical buds and roots,young leaves, embryo.Promote seed and bud germination,stem elongation,and leaf growth;stimulate flowering and development of fruit;affect root growth and differentiation
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Abscisic acid background info?
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found in leaves,stems,roots,green fruit.Inhibit growth;closes stomata during water stress;promotes seed dormancy
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Ethylene background info?
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found in tissues of ripening fruit,nodes of stems,aging leaves and flowers. Promotes fruit ripening, opposes some auxin effects;promotes or inhibits growth and development of roots, leaves, and flowers, depending on species
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Apical dominance vs. Branching auxin vs cytokinin?
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auxin enforces apicaldomin. and is produced in the apical bud. Auxin travels down from the apical shoot bud into the plt body by diffusion, auxin inhibits cytokinin,cytokinin induces axillary branching.Cytokinins are produced in the roots and travels upward into the plt body.
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What is teh common limiting factor to plt growth?
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water
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If water is the limiting factor, what would happen if branching and leafing-out during growth was to outstrip the root system's ability to supply the plt body with water?
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a drop in turgot would lead to wilting.
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what is the pattern of auxin and cytokinin distribution and action during development of the adult plt body?
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Auxins from apical bud will enforce apical dominance(few leaves,less demand for water)until the plt reaches normal height.Then the apical bud will become senescent.Then as the roots continue to grow and produce the cytokinins, the cytokinins will increase in conc. As more cytokinins are prodcued, they will eventually move up theplt stem, break apical dominanceand allow the plt to branch out fully.
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ABA gibberellins and seed germination in desert plts?
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ABA generally inhibits growth.ABA is good for causing leaves to drop(abscission).ABA prepares buds for winter:cease growth become cold/drought tolerant(senescence).ABA enforces seed dormancy during winter or drought.
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What do gibberelins stimulate?
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fruit development,stem elongation(foolish rice disease) and seed germination
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Dormancy for desertplts?
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a balance of conc. between ABA and gibberellins that balance enforces dormancy, important for survival in the hot summers.seeds must wait for the winter rains to germinate
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ABA and gibberellins and desert rains what happens?
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ABA is more adhesive to water than the gibberellins.Desert winter rains can wash out ABA more rapidly than the gibberellins from the seed.This causes the gibberellins to be in a higher relative conc. after rain.Seed dormancy will be broken and the seed will germinate when water is available.
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What are tropisms?
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tropisms are growth responses towards or away from a stimulus.
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gravitropism
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response of a plant to the force of gravity
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phototropism
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an orienting response to light
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thigmotropism
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growth in response to touch, touching a plt at a site, slows growth at that site. if one side or tendril is touching something that side will grow slowly and the other side will grow more quickly. thought to be due to increased ethylene in response to mechanical stimulation>>decreased cell elongation at site of stimulation.
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circadian rhythm
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responses that are based on a 24hr time period
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biological clock?
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the internal clock that allows circadian rhythms to occur. Biological clocks are usually set by the light/dark cycle of the sun.The molecular mechanism is still under investigation.biological clocks probably occurs in all Euk.,therefore evolved early in life's history
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biological clocks modulate these things?
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what is metabolism/metabolic rate, cell division rate, blood ceel deposition into blood stream, alertness, others.
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in plts bio. clocks also modulate
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metabolism,metabolic rate, opening and closing of stomata, legume sleep movements, long term growth responses to day length,etc.
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photoperiodism
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response of plants to periods of light and darkness
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why do plts need to tell when a the change of season occurs?
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seed germination, flowering, entering or breaking winter or summer dormancy. done by determination of relative length of day vs. night photoperiod
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what did the study of Maryland Mammoth show in plts?
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it grew tall in summer, but would not flower during the summer, finally flowere in Dec. in a greenhouse.only floweres in shrt. winter days, by manipulating the daylight period so that day was 14hrs or shorter they were able to induce flowering.
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what is a short day plt?
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a plt that induced flowering in a shrt day. soy and pointsettias are among the other plts that flower in fall or winter in response to short days.
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Long day plts?
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plts that flower when days are longer than a certain period of time. long day plts flower in summer like spinach flowers if days are longer than 14hrs.
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day neutral plts?
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flower at certain maturity stage and are not photoperiodic ex.tomato. the nomenclature of photoperiodism is very poor and confusing.
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what was later discovery about plts, and day and night lengths?
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it wasnt really day length but night length that was the controlling factor.
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why is night length critical?
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short day plts are really long night flowering plts.(cocklebur require at least an 8hr night to flower) discovered by night interrupted by short period of light-no flowering.night not interrupted by short period of light=flowering
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night length and manipulation of flowering plts what does it change?
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floriculture industry uses this knowledge to manipulate the greenhouse lights and produce flowers out of season. the effect is for vegetative meristems to become floral meristems.
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how is light detected in theplt?
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by leaves, effects is seen in the buds, because of that flowering is though to be hormone controlled but the hormone has not been found
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what is it in the leaves detects the light period changes?
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a light absorbing protein pigment called Phytochrome exists in leaves. all pigments abs. different wavelengths of light differentially and phytochromes is no exception. the protein is a dimer and an enzyme and it exists in 2 states.
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what does red light do to a phytochrome?
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it can be turned on and off by red light. if phytochrome is flashed with red light in the night it is interupted and flowering is inhibited.Night is interrupted=nights are short(days are long). for this late summer flowering plt this mimics the light of summer,in amount and quality(=no flowering)
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what if you shine red light on a plt again?
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the phytochrome is converted toother form.makes the plt think that the nights are getting longer.(no interruption) the plt will flower, mimics light in late summer in amt and quality(=flowering) furthermore, the experimenter(tormentor)can do this as many times as he/she likes.it is the last flash of light that will leave the phytochrome in the active state or not.(i.e. phytochromes are photoreversible and are inplts to measure the length of night)
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phytochromes allow plt toadapt to certain conditions?
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day/night length, light intensity,light quality(wavelength)
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phytochromes allow fine tuning of?
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flowering time,growth spurts,breaking dormancy, seed germination.
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Ethnobotany define?
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the use of plts by man for food and medicine and the impact on the culture of man.
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ethnobotany origins?
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it can be argued that ethnobotany began even before hominids became human. the gathering of certain preferred plts over others impacted migration patterns,(cave sociology" and social hierarchy.scientists see the same kind of interactions in gorillas and chimps today.
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How is maize an example of ethnobotany?
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was domesticated in Teohuacan Mex before 6000 years ago by the ancestors to the aztecs.Maize is unable to survive in the wild,therefore it must be a product of domestication. the husk doesnt open so seeds wont disperse.the seeds permanently attached to the central axis,again seeds wont disperse(but a big plus for a domestic crop) seeds are not well protected from animals.
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what is the ancestral plt to Maize and background info?
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Teosinte, has the same general configuration as Maize but several factors which make it less suitable as a crop plt than maize. few kernels. no protective husk,but individual carpels which are woody and difficult to remove, kernels disperse easily.
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what did a rare species of teosinte tell us about plts?
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only known source of several genes that were protective against viral diseases of corn. these genes have been added to domestic corn inthe US, the rare teosinte is found only in a few hundred acres of rainforest near Guadalajara and could have been easily been lost to clearing for agriculture.
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How is cotton an example of ethnobotany?
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Was domesticated twice, once in old world and once in South America. known because old world cotton is diploid and New World is polyploid.Once New World cotton made it to the Old World after 1942, it quickly replacedit.
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how are potato and other tubers an example of ethnobotany?
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originally domesticated in the Andean highlands.A great variety still is cultivated by natives of the andes.Still a great source of genetic diversity for breeding against pests and for other agriculturally useful characteristics.an important food crop world wide(Poland,Russia,Ireland,etc)
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role of ethnobotany in the establishment of human civilization.
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anthropoligists consider the change from hunter/gatherer societies to agricultural societies to be the point at which civilization began(about 10,000 years ago). By definition, civilization required the domestication of plts and animals to carry out agriculture.
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Where did plt domestication begin and how?
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probably began in the fertile Crescent, from wild seed of food producing plts and were planted and over time better varieties were selected and planted again. This is an example of artificial selection and is the basis of crop Breeding Science. first plts to be domesticated were wheat and barley
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how did plts influence early society?
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rice based cultures of Asia. Maize based cultures of Central America and Mexico.Wheat based cultures of Middle east and Eastern Mediterranean.
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when did the industrial revolution begin and what is it?
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1850, beginnings of mass production of goods with interchangable parts(before this each was hand made)Items such as farming equipment,guns,household items were much more available and much cheaper to buy.In time, agriculture became industrialized as well.included mass planting and mass harvesting,this created a demand for crops that ripened at the same time.
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demands for other cultural characteristics also increased during the green revolution?
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greater yield, pest resistance, drought resistance , cold tolerance.
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crop breeding what it is and when it came about?
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desired characteristics were added to plts the same way they always had:Artificial Selection(in this case known as Crop Breeding). This occurred from the late 1800's and continues to this day.until recently technology was responsible for nearly all food you eat. the resulting crops that produce 10 to 100 greater yields, resist a variety of plant pathogens and can withstand cold and drought better were known as products of the Green Revolution.
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positive Consequences of the green Revolution?
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the tremendous increases in yield afforded by the green rev. positively affected world nutrition and health. Crops produced by Green rev. were tailored to specific climatic conditions which then gave much better yields that before(spring wheatvs. winter wheat) The green rev. era also saw the greatest increase in world population.the long term consequences of this are unknown but are potentially catastrophic.
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what has the green revolution done to genetic diversity of crop plts?
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it has decreased greatly leaving crops vulnerable to new diseases. before the green revolution each person or region had its own variety of crop plts. these different varieties had a full range of genetic diversity.not now;epidemic of wheat rust(2009) and corn smut(1972)
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what is the new era of genetic engineering?
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starting in the 1980s direct manipulation of the genome began. Genes could be directly picked for introduction into crop plts. pest resistance, disease resistance cold tolerance drought tolerance herbicide resistance nutritional genes.
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What are some pluses to genetic engineering?
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can respond more rapidly to changing conditions(although doesnt apply to all situations) better control of genes/more direct manipulation,can add genes from unrelated species
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What are some minuses to genetic engineering?
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public perception(frankenfood) unintended hybrids(canola or rapeseed and mustard)
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What are industrial farming techniques?
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irrigation(water depletion,salinization).fertilizers(limited supply,expensive,polluting)pesticides/herbicides(limited supply,expensive,polluting).tilling(soil loss)lo
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What will feeding a growing world require in the future?
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local food production(fewer food supply lines that use energy for transport,also avoids the pitfalls of industrial agriculture).alternative crops(e.g.amaranth).decrease world populations(ZPG). genetic engineering(adding salt tolerance, increase nutrition)
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how are desired traits in organisms identified?
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marker assisted selection uses gene chips of agricultural organisms. organisms that are identified with desired traits with the gene chips are then breed by conventional means and selected for the desired traits.Outcome is a crop organism with the traits you want but are not genetically modified(not GMO's)
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Medicinal plts?
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traditional culture have utilized plts and fungi for medicinal and cultural uses. most all of them are secondary metabolites which are compounds produced to fend off herbivores,yell for help or wage war. examples of compounds discovered by indigenous peoples. cocaine(Erythroxylern coca,painkiller).morphine(papaver somniferum,painkiller).curare(heart muscle relaxant) mescaline(Lophophora williamsii,hallucinogen)
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what are some examples of secondary metabolites from plts or fungi currently in use?
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curare,morphene,taxol(pacific yew,cancer drug),penicillin(penicillium sp,antibiotic) aspirin (salix sp. painkiller) many others.
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Where are most medicinal plts found?
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most medicinal plants are found in tropical forests(which are being rapidly lost to agricultural clearing.
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What is the importance of plts?
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produce oxygen.fixes CO2.provides 70% of worlds protein.Nearly all medicines until about 1990 was derived from plts or fungi(many still are).Maintains habitats.Stores CO2.Provides wood products.Aesthetic value.
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Characteristics of anthophyta?
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1) Most diverse and wide spread group of plants with 300,000 species known (and there are many more yet to be discovered)
2) almost all agricultural plts are angiosperms and they supply most of the plt derived medicinal chemicals that are known 3) highly diverse in number, size and form |
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What are the 4 basic types of angiosperms?
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monocots, eudicots, Basel angiosperms , Magnolids
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monocot characteristics?
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one cotyledon , leaf veins parallel , vascular bundles , scattered in stem , fibrous root system, flower parts in 3's( grasses palm lily)
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Eudicot characteristics?
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2 cots , veins net-like in leaves, vasc bundles have ring arrangement in stem , tap root , flower parts in 4 or 5s ( roses avocados , peas , oaks.)
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New characteristic of angiosperms over gymnosperms?
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flowers
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What do monoecious flowers have?
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Monoecious flowers have the male androecium and the female gynoecium in the same flower in addition to the sterile parts of the flower(calyx and corolla)
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What does the gynoecium consist of? And the androecium?
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Gynoecium: carpels ( megasporophylls = ovary + stigma + style.)
Androecium: Stamen (filament + anther) |
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Are monoecious angiosperms incompatible?
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yes
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Characteristics of dioecious plts.
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the staminate flower and the carpellate flower are on different plts.
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origin of flower petals
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most extant flower petals evolved from sterilized stamens, not leaves.
evidence: (a) petal vascular pattern matches that of stamens and not leaves (b) archaic stamens are often of various shapes, colors, may even be scented, or broad and fleshy (c) molecular evidence confirms this view |
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What can animal pollination do for plants?
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gives delivery of male gamete to female gamete.
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How have some flowers co-evolved with animal pollinators?
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flowers have evolved to where only a single animal can pollinate that particular flower.
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Fruits have TWO mature ovaries.
2 types of mature ovaries: |
Dry and Fleshy fruits
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characteristics of dry fruits?
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protective( peas in a pod) help in seed dispersal ( maple seed wings)
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Characteristics of fleshy fruits?
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FLESHY FRUITS have fleshy pericarp
(1) pericarp develops from ovary walls (2) form a "bait" that animals will eat and carry away and help in seed dispersal (apple, tomato, banana) |
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Where does pericarp develop from?
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ovary walls
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Definition of a simple fruit?
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develop from 1 carpel or a few fused carpels that make a single fruit.(grape apple)
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Definition of an aggregate fruit?
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many individual carpels of a single flower. sometimes fused, often not aggregate to form a fruit ( strawberry raspberry)
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Definition of a multiple fruit?
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many separately fertilized gynoecia fuse to form the fruit.(pineapple)
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Berry characteristics?
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simple fruit type, one to many carpels , each with many seeds, carpel wall is fleshy(grape tomato)
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Drupe characteristics?
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one to many carpels each with 1 seed, inner carpel wall is stony and adheres to the fleshy portion of the enlarged carpel wall( cherry peach) simple fruit type
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Pome characteristics?
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compound inferior ovary , where the perianth enlarges and become fleshy, 1 seed per locule. (pear apple) simple fruit type
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How is a fruit to be known as an accessory fruit?
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if a fruit contains parts other than just the enlarged pericarp, then the fruit is known as an accessory fruit.
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Strawberry characteristics?
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fruit is an enlarged receptacle with the seeds on the outside. it is an aggregate fruit ( individual fruits are fused) and an accessory fruit
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pineapple characteristics?
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pineapple fruit is many separately fertilized gynoecia fused to form the fruit with other flower parts squeezed between. A pineapple is a multiple and accessory fruit.
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coconut characteristics?
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Coconut has 3 carpels. The fused outer carpel walls are a fibrous husk. The flesh is solid endosperm of the seed and the coconut milk is liquid endosperm. The embryos float in the liquid endosperm.
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In the angiosperms what is the microgametophyte?
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a 3 celled pollen grain
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In the angiosperms what is the megagametophyte?
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7 or 8 celled embryo sac
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What is the process of microsporogenesis?
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cells in the anther develop into diploid microsporocytes(microspore mother cells). microspore mother cell undergoes meiosis to form 4 haploid pollen cells. each pollen cell undergoes mitosis twice to form 4 haploid cells of which 2 or 3 survive and develop into a mature pollen grain or microgametophyte, usually 2 of the 3 cells of the microgametophyte are sperm cells
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What is the process of megasporogenesis?
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in the early ovule there is the nucellus(the megasporangium) and a single diploid megasporocyte(megaspore mother cell) megaspore mother cell undergoes meiosis to from 4 haploid megaspores. 3 of 4 megaspores disintegrate and the remaining cell forms the megagametophyte. the nucleus of the megagametophyte undergoes mitosis 3 times to form 8 haploid nuclei. The 8 nuclei undergoes development into 7 different cells, one of which has 2 nuclei(the central cell). but only limited cell division occurs. This structure is the embryo sac and is the mature megagametophyte.
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What are the important cells of the embryo sac?
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egg cell & polar nuclei of the central cell
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What is the fertilization process in angiosperms?
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pollen lands on the stigma and a tube germinates from the pollen grain(pollination)Pollen tube contains the tube nucleus and 2 sperm cells. Tube grows down the stigma to the ovule and enters through the micropyle.Upon entering the embryo sac, the pollen tube disgorges the tube nucleus and 2 sperm cells.One sperm fuses with the egg cell to make the zygote & the other fuses with the 2 polar nuclei of the central cell= double fertilization.
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What five reasons make angiosperms so effective
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1. gametophyte generation is much reduced, sporophyte dominates.2. vulnerable gametophytes held and protected in the robust sporophyte. 3) direct, efficient delivery of gametophytes to each other, usually aided by animals
4) resulting embryo well protected & provided with food by seed and sporophyte.5) several mechanisms to ensure out-crossing including |
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Mechanisms that ensure out-crossing?
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(a) some flowers contain only one of two sets of sex organs (dioecious) and so there are staminate and carpellate plants
(b) different times for ripening of male and female flowers (c) self-incompatability. |
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Angiosperm evolution timeline:Silurian Period?
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1st fossil vasc. plts 440 mya
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Angiosperm evolution timeline: Devonian Period?
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Devonian Period (~408 mya): 1st fossil vasc. plts disappear from fossil record, diversification of later lycophytes, pteridophytes & seed ferns.
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Angiosperm evolution timeline:Permian period?
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(~290 mya): 1st fossil gymnosperms, later diversification of gymnosperms, lycophyte trees, seed ferns eventially disappear
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Angiosperm evolution timeline:Cretaceous period?
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(~145 mya): 1st fossil angiosperms; by 90 mya, diverse and dominant
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What is a theory to an angiosperm ancestor and why is it contested?
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Recent morphologial and molecular analysis point to the Bennettitales or one of the extinct Gnetophytes as the most likely candidates for Angiosperm ancestors.Bennettitales and Gnetophytes 1st appear in the fossil record 225 mya. If they are the ancestors of the angiosperms, then angiosperms are less than 225 myo. Some believe that that is not enough time to evolve the diversity seen.
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What similar characteristic is found in bennettitales and gnetales that is similar to angiosperms?
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flower-like reproductive structures.
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What suggests that angiosperms are monophyletic?
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many, highly specific characteristics occurring in Angiosperms is strong evidence that Angiosperms are monophyletic
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earliest angiosperm fossil found in what year?
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earliest Angiosperm fossil plt parts are 130 myo
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Earliest complete fossil angiosperm known is?
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Archaefructus (125 mya) had closed carpels but lacked modern flowers.
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What are Basal Angiosperms?
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(c) morphological evidence indicates that many of the basal angiosperms split from the monocots and eudicot line before the monocots and eudicots split) make up only 3% of living Angiosperms (b) neither monocots or eudicots
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What are some ancestral characteristics found in various basal angiosperms?
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single aperture pollen •sepals and petals undifferentiated •4 whorls separate, not fused (calyx, corolla, gynoecium, androecium) •Most archaic: flower parts in spiral, not whorls •flowers with radial symmetry •stamens very diverse, no set structure •carpels open, unspecialized for pollinators •ovary superior •flower part numbers indeterminate
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Are the Basal Angiosperms clues to Angiosperm evolution
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Answer is yes, the basal Angio's give clue to the origin of Angiosperms in that some of the ancestral states are seen in the basal Angio's
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Is a magnolia a Basal angiosperm?
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NO but share some characteristics
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Characteristics of Amborella trichopoda
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•They have tepals (no sepals or petals). Tepals are in a spiral (no whorls present)
dioecious with imperfect flowers. Overall the flower are small, simple and not "showy" |
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Found only in New Caledonia
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•Amborella is the only genus in its family
Therefore clearly is a remnant family from earlier epochs |
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What is the earliest extant angiosperm?
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AMborella
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What are the Basic Evolutionary trends in flowers?
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(a) ancestral flowers: many parts, indefinite in #. Modern flowers: few parts, definite # of parts.
(b) ancestral flowers: flower parts in spirals or 4 separate whorls of floral parts modern flowers: whorls fused/reduced to 1, 2 or 3 (c) ancestral flowers: ovary superior modern flowers: ovary inferior (d) ancestral flowers: radial symmetry modern flowers: bilateral symmetry |
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Co-evolution of flowers and animal pollinators?
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The driving force in evolution is making sure that the genetic material is passed to the next generation.
(a) Therefore any change that aids in passing the genetic material to next generation is very likely to be retained through natural selection. (b) Since animal pollination is a very efficient method of passing pollen to the gynoecium, structures that aid in that process are strongly selected for. (c) The same applies to animal pollinators, as the flowers are animal's food source. |
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Examples of Co-evolution of flowers and pollinators
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(a) Hummingbirds/Monkey flower
(b) Bees and many flowers (e.g. Rosemary) |
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Hummingbirds/Monkey flower
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(1) Flower has long, tubular corolla. Excludes bees & beetles, long beak of hummingbird can easily access nectar(2) lots of nectar, necessary to attract a bird(3) stamen positioned so that anther "dusts" head of hummingbird with pollen as it feeds.
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Bees and many flowers (e.g. Rosemary)
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Bees: •tongue is a tube for sucking nectar •have pollen collecting combs on legs
•have pollen baskets on 3rd pair of legs collect pollen from the combs Rosemary: •Stamens, stigmas curve upward to touch a visiting bee: exchange of pollen assured •lower petal is a specialized landing platform that correctly positions bee to exchange pollen with the flower •other adaptations |
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Family Asteraceae: examples of a highly derived flowers?
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radial Disk flowers + bilateral ray flowers: composite
2) Disk flowers (many flowers on a head) (a) 5 fused stamens (b) 5 fused petals, also fused to ovary (c) inferior ovary (epigynous) (d) sepals often absent 3) bilateral ray flowers (sometimes sterile |
