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122 Cards in this Set

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Biodiversity
“Biological diversity”. Can be broken down and further defined depending on the subject. Genetic diversity, species diversity, and ecosystem diversity. Biodiversity is not a state! Changes though time
Biodiversity is not a __________
“state” It changes through time.
Genetic Diversity
the total genetic information contained within all individuals of a species
Species Diversity
variety of species in a specific location (global, USA, your tongue, etc). Defined through BOTH the number of species and the umber of each species.
Ecosystem Diversity
The variety of biotic communities in a region along with abiotic components (soil, air, etc)
Number of species described
1.5 mill
Number of species estimated to exist
5-8 mill
First person to categorize life
Aristotle
Aristotle’ life categories
Plant or Animal (land, water, or air)
Carolus Linnaeus
decided on a life categorization system based on structure and function. Developed binomial nomenclature. Lived in a very chaotic time for science
5 Kingdoms –
1) Kingdom monera (prokaryotes), 2) kingdom protista (unicellular eukaryotes), 3) kingdom plantae, 4) kingdom fungi, 5)kingdom animalia
Binomial nomenclature
developed by Carolus Linnaeus. Identifies species through “Genus_Species” form
Did King Phillip Came
Over From Germany Stoned? Domain Kingdom Phylum Class Order Family Genus Species
Carl Woese
Suggested grouping organisms according to DNA instead of appearance similarity. Resulted in the Tree of Life. Practice is called “Phylogeny”
Blending inheritance –
claimed that traits observed in a mother and father blend together to form the traits observed in their offspring
inheritance of acquired characters –
claimed that the traits present in parents are modified and passed onto their children (giraffe neck)
particulate inheritance –
small particles (traits) are mixed and inherited from the parents
Phylogeny
the study of evolutionary relatedness among groups of organisms. Based on DNA/RNA
Non-linear steps of the scientific method
Observation. Question. Hypothesis. Prediction. Test. Gather Data. Conclusion. Share
Benefits and outcomes, exploration and discovery, and community and analysis are all interrelated with
the actual testing of ideas.
The three aspects of a good scientific question:
1)A good question can be tested, 2) Builds on what you already know, 3)leads to more questions
Fitness
how man offspring are left behind. Not necessarily about physical fitness, more like reproductive fitness.
Hypotheses
proposed explanations that make testable predictions
4 Main postulates of Natural Selection
1)Individuals have different traits within the species. 2)Some variations or hereditary, 3)more offspring are produced than can survive, 4)offspring with beneficial traits are more likely to survive and reproduce
Alfred Russel Wallace
developed natural selection also. Published a paper with Darwin.
Name of Darwin’s boat –
The Beagle, 18/31-36
Lamarck –
Thought of evolution as a ladder
Descent with modification
Change over time results in modern species from an ancestral species. Change through time IS occurring but everyone is still related via a common ancestor,
Examples of changes through time
Fossils, extinction, transitional forms, vestigial traits, geographic relationships, homologies
Example of transitional forms
“Fishapod”, Tiktaalik
Tiktaalik A transitional species thought to be the link between fish and land animals
Vestigial Traits
Structures that have little/reduced function. Example: Tailbones, goosebumps, blind fish with eye sockets, flightless birds w/ wings, wisdom teeth
Geographic relationships
4 Different versions of the mocking bird on one island -> Darwin would have proposed that they had a common ancestor and shared a spot on a phylogenic tree
Analogous traits
Similar traits that did not evolved from a common ancestor. Such as bats and birds who both have wings
Homogies
similarities due to a common ancestor
Genetic homology
similarity in DNA
Developmental homology
similarity of certain prenatal aspects
Structural homology
Similarities across adult morphologies (femur connected to the radius)
Mendel’s experiments worked because of 3 aspects:
1) Control over fertilization, 2) Either/or characteristics, and 3) True breeding parents
Particulate inheritance:
genetic information is inherited in discrete units. Offspring traits are not a smooth blending of parental traits.
Mitosis:
Nuclear division resulting in two daughter cells
Parental and Daughter cells have _______ genetic material.
identical
Cytokinesis:
Division of cytoplasm in cell into two daughter cells
Frequency of crossing over:
at least once every meiotic division for each chromosome
Linkage map -
Made by looking at the frequency of recombination of alleles of a gene in offspring.
Meiosis:
formation of sex cells (gametes)
Flemming –
(1879) noticed the thread-like structures in the nucleus that could be made visible with certain dyes. Provided an early technique for studying nuclear and cellular division
Complications to medelian genetics –
1) Traits with multiple alleles, 2) polymorphic traits, 3) Codominance, 4) Pleiotropy, 5) Physical Environments Impact Genes, 6) Genetic Environment: impacts phenotypes, 7) Quantitative Traits
The four main steps of the cell cycle:
G1, S, G2, and M.
G1 and G2 –
The “gaps” in the cell cycle. Where the cell grows. When combines with “S” the three phases are called “interphase”
Interphase –
the nondividing phase of the cell cycle
S phase –
when the replication of genetic material in the cells happens
M phase –
“mitotic phase” when cells are dividing.
The 5 sub-phases of the mitotic phase are
1) Prophase, 2) Prometaphase, 3) metaphase, 4) anaphase, and 5) telophase.
1) Prophase –
Chromosomes condense, mitotic spindles form
2) Prometaphase –
spindle fibers attach from each of the mitotic spindles to the sister chromatids.
Kinetochores –
where mitotic spindles attach
3) Metaphase –
“middle phase” when the chromosomes are lines up along the middle plane of the cells
Metaphase plate –
middle plate that the chromosomes line up on in the metaphase
4) Anaphase –
splitting of the centromeres. Separation of sister chromatids. Shortening of spindle fibers as the chromosomes separate.
5) Telophase –
end phase. The cell finishes its separation.
Sister chromatids –
the two strands of a replicated chromosome.
Centrosome –
the microtuble organizing center in animals
Centriole -
Cylindrical structures that compromise microtubules, located inside animal centromeres
Zygote –
a fertilized egg
Karyotype -
number and types of chromosomes present
Recombination –
the result of crossing over
Mitosis:Meiosis Comparison: Number of cell divisions –
Mitosis: one, Meiosis: Two
Mitosis:Meiosis Comparison: Number of chromosomes in daughter cells compared to parent cells –
Mitosis: same, Meiosis: Half
Mitosis:Meiosis Comparison: Number of crossover events –
Mitosis: None, Meiosis: One or more per pair of homologous chromosomes
Mitosis:Meiosis Comparison: Make up of chromosomes in daughter cells –
Mitosis: identical, Meiosis: Different
Mitosis:Meiosis Comparison: Number of daughter cells –
Mitosis: 2, Meiosis: 4
Explanation for sex: Purifying Selection Hypothesis –
If a gene is damage it will be inhereited by all of the offspring of an asexually reproducing individual while half of the offspring of a sexually
Explanation for sex: Changing Environment Hypothesis (eg parasite) –
Being genetically identical is fine if the environment is the same. However, having variation is important because biotic and abiotic environments can change quickly. “In an environment that changes it is beneficial for parents who are poorly adapted to the new environment to produce offspring who genetically different from the parentals.”
Multiple alleles –
when there are more than 2 alleles for the same gene
Polymorphic traits -
When more than two distinct phenotypes are present in a population due to multiple allelism
Incomplete dominance -
Neither allele is completely dominant over the other. Result: heterozygous offspring have intermediate phenotype to parental phenotypes
Codominance –
where the homozygous recessive and homozygous dominant appear together in separate phenotypes.
Pleiotropy -
a gene that affects more than one phenotype
Physical Environments Impact Genes -
Phenotypes produced by most allele combinations are impacted by an individual’s environment
Genetic Environment: impacts phenotypes.
Example: comb shape depends on two genes that interact ( R & P ). The phenotype produced depends on the alleles present for the other gene.
Quantitative Traits –
Phenotypes that produced by multiple genes. Phenotypic histograms of traits in a population with quantitative genes often result in a normal bell curve. Phenotypes are exhibited over a smooth scale (eg, human height). Are the result of many genes interacting?
Hardy & Weinberg -
imagined that all of the gametes produced in a generation go into a single group called the gene pool and then combine at random to form offspring.
Assumptions of the Hardy-Weinberg Equilibrium -
1.No selection (natural or artificial) 2. No genetic drift (very large population size, no sampling effect) 3. No migration (no gene flow in or out) 4. No mutations (change in form of an allele – the ultimate source of genetic change) 5. Random mating
Directional selection
An area is selected against and the normal distribution shifts, tends to reduce genetic diversity within populations but only if selection pressure is constant (not yearly variation) and no strong counterbalancing selection pressures
Stabilizing selection
no change in average value of trait, but a decrease in variation (due to low fitness of the outliers on both sides)
Disruptive/Diversiying selection
happens when the outliers on each side have higher fitness than the average. Can result in balances polymorphism or speciation
Genetic drift –
change in allele frequency due to random events. Biggest impact is on a small population.
Possible versions of genetic drift –
fixation, bottle neck effect, and founding event
Fixation –
allele ratio becoming 1. As in the only allele option in the population
Bottleneck Event – population drastically reduced in size by chance without regard for fitness. By chance, some of the survivor’s alleles may be over or under represented.
Founding event – New population starts with a few individuals not genetically representative of a larger source population.
Inbreeding reduces __________ heterozygosity and fitness (No change in allel frequency, just change in genotype frequency)
Species – latin for “kind/appearnce”. Introduced in 1942 by Ernst Mayr Species are a distinct type of organisms and represent evolutionarily independent lineages.
Biological species concept: Individuals within a species can potentially 1) interbreed to 2) produces viable, 3) fertile offspring. Must be reproductive isolations between species.
Limitations to Biological Species Concept:
- Impractical or impossible to asses fossils, asexual reproducers.
- Many living sexual species that are closely related byt do not overlap geographicly
How are organs isolated from each other?
1) Prezygotic barrier: (sex never happens) Habitat isolation, behavioral isolation, or temporal isolation. In mating: Mechanical isolation (structural differences in gentalia), Gametic isolation (gametes don’t recogniz each other)
2)Postzygotic barrier: Reduced viability, reduced fertility, or hybrid breakdown
Morphological Species Concept: Species are defined by difference in shape size, or other features. Benefit: Widely applicable. Downfalls: which traits and how much difference is enough? Cannot tell the difference between cryptic species.
large population drastically reduced in size by chance without regard for fitnesss. By chance, some of the survivor’s alleles may be over or under represented.
Bottleneck Event –
large population drastically reduced in size by chance without regard for fitnesss. By chance, some of the survivor’s alleles may be over or under represented.
Phylogenic Species Concept:
based on reconstruction of evolutionary history of population. Disadvantages: data not widely available (unknown species). Expensive. Advantages: widely applicable (fossils) and logical
Monophyletic group –
an evolutionary group containing an ancestral population and all of its descendants (Monophyly)
Paraphyletic group –
An evolutionary group that includes an ancestral population and some but not all of its descendants. (Paraphyl )
Polyphy:
group whos member’s last common ancestor is not a….**
Homology –
(same source) traits are similar due to common ancestor
Homoplasy -
(same form) similarity among organisms due to convergent evolutions
Cladistic approach –
method of photogenic tree construction that is based on identifying the unique traits of each monophyletic group
Parsimony –
the idea that most likely explanation for a phenomenon is the simplest (most economical)
Synapomorphy –
a trait found in certain organism that doesn’t exist in others. Unique to it’s monophyletic group
Phologentic tree: tip –
species
Speciation –
splitting events leading to the formation of two or more distinct species from a single ancestral lineage.
Recipe for speciation:
1) Genetic isolation due to lack of gene flow. 2) Genetic divergence due to selection, drift, mutation, etc.
Result of high gene flow –
populations remain homogenous in terms of allelic composition.
Result of low gene flow –
populations may diverge due to mutation, selection, and drift
Two primary modes of specification:
1) Allopatric speciation, 2) Sympatric speciation
Allopatric speciation –
geographic separation restricts gene flow. Can happen through a) dispersal and colonization and b) Vicariance (change of geographic boundary)
Vicariance –
change of geographic boundary
Sympatric speciation –
biological factors restrict gene flow. Can be caused by 1) Disruptive selection - a gene-based shift in habitat or mate preference- or, 2) Polyploidy
Disruptive selection -
a gene-based shift in habitat or mate preference. (Hawtorn flies vs apple flies)
Polyploidy –
the state of having more than two paired homologous sets of chromosomes. It is a particular type of mutation that reduces flow between mutants and non-mutants individuals. Is a very quick path to a new species
Triploid individuals are virtually always _______
sterile
Types of polyploidy:
Autopolyploidy – arises if there is a genome doubling and fusion of 2n (diploid) gametes (maidenhair fern). Allopolyploidy – generated by “other” species. They have chromosomes set from different species.
What happens when isolated populations come into contact?
1) Reinforcement of divergence, 2) Founding of stable hybrid zone, 3) Speciation by hybridization, 4) Fusion of populations, or 5) extinction of one population
Reinforcement of divergence –
selection for mechanisms that prevent previously isolated populations from interbreeding.
Hybrid zone formation -
an area where interbreeding occurs and hybrid offspring are common.
Fusion of populations –
can create a new, independent species from the hybrids
Inbreeding depression –
in inbred offspring, fitness declines due to negative recessive alleles that are homozygous
Gene flow _________ allele frequencies between populations
equalizes
Phylogenetics: a ______ depicts a population through time
branch
Phylogenetics: a _______ is the point at which two branch diverge.
Node
Phylogenetics: a _____ (or terminal node) the endpoint of a branch represents a group (species or larger taxon) that is living today or ended in extinction
tip