Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
175 Cards in this Set
- Front
- Back
Prokaryotes
|
a type of cell lacking a membrane enclosed nucleus and membrane enclosed organelles -unicellular and small, achieve all of life's functions within a single cell |
|
Features of prok
|
chromosome in nucleoid, fimbriae, ribosomes, plasma membrane, capsule, flagella
|
|
shapes of bacteria
|
spherical, rod-shaped, spiral
|
|
cell wall
|
protects the cell, prevents bursting, maintains shape -Bacteria made of peptidoglycan -Archaea have polysacharides and proteins -euks have cellulose or chitin |
|
Gram stain
|
used to classify bacteria by cell wall composition -gram positive: thick peptidoglycan(traps crystal violet) -gram negative, less peptidoglycan and an outer membrane may be toxic, outer lipopolysacharide (crystal violet easily rinsed away, revealing red dye) |
|
Capsule
|
Cell surface structure: capsule is sticky layer of polysacharide or protein: works for attachment aid or desiccation protection or protect from host immune system
|
|
Fimbriae or pili
|
cell surface: allow them to stick to their substrate or other individuals in a colony: fimriae hair like protein appendages, called atttachment pili |
|
Sex pili
|
longer than fimbriae that allow proks to exchange DNA
|
|
Flagellum
|
common structure used by proks for directional movement: can be spread over entire cell or on one or both ends, smaller than ones on euks
|
|
evolution of flaggellum
|
made by series of simpler proteins that lines up and continue to form up. ATP synthase of membrane line up with other transport proteins. signal transduction proteins bind to protoflagellum linking its function to state of environment, chemotactic flagellum as proteins keep binding extending the flagellum -video: gradual steps towards selective active transport apparatus to move proteins from the cytoplasm to the extracellular environment (some parts include atp synthase, secretin and pores); Then adhesive protein gets secreted by system but remains bound to secretin and further of this forms pilus |
|
Irreducible complexity
|
some things so intricate and complex that no way that it could function if it were less complex or sophisticated. only conclusion is that products of intelligent design
|
|
Exaption
|
process in which existing structures take on new functions through descent with modification example is prokaryotic flagellum |
|
taxis
|
ability to move toward or away certain stimuli (motility) chemo taxis moving toward or away from chemical signal/nutrient phototaxis movement based on light |
|
Nucleoid
|
region in the prok that contains dna genome(very small, tightly compacted and compressed)
|
|
plasmids
|
bacterial dna separate taht are smaller, up to 600 copies of it per cell with up to 100 nucleotides, helps confer antibiotic resistance; can exist independently or integrated into chromosome |
|
Genetic diversity
|
Rapid reproduction, mutation, and genetic recombination
|
|
Prok reproduction
|
reproduce quickly by binary fission; replication begins at origin of replication and both copies move toward opposite ends of cell, once replication finished, membrane grown inside, new cell wall deposited and two daughter cells
|
|
Reproduction of plasmids
|
for high copy, random partitioning, random segregation of plasmids into daughters, for low copy, replication coordinated with chromosome replication, partitioned into daugter cells----- plasmids can be passed on integrated or not integrated into the chromosome |
|
Rapid reproduction/mutation
|
as quick as 1-3 hours, cold outweight earth in one day if <10 minutes; mutation rates low but because rapid, chances for mutation more likely, high diversity allows for rapid evolution |
|
Selection for GASP phenotypes
|
Growth advantage in stationary phase: 5 stages: lag, exponential growth, stationary, death, long term stationary example: starvation by bacteria after stationary select for ability to break down amino acids for source of carbon and energy; mutation in genes can serve as basis for GASP phenotypes |
|
Genetic recombination
|
combining of dna from two sources which adds to genetic diversity: done by transformation, transduction, and conjugation
|
|
Transformation:
|
prok cell can take up foreign dna from surrounding environment, dead cell dna enters live cell and incorporates dead cell dna in homologous region of live cell's genome
|
|
Transduction
|
the movement of genes between bacteria by bacteriophages. Phage invades bacteria cell and goes though viral reproduction process then when it enter lytic cycle, part of bacterial genom enters capsid of phage and when that phage attaches to new cell, the bacterial genome integrates at homologous region in new recipient cell
|
|
Conjugation
|
process where genetic material is transferred between prokaryotic cells, dna only transfer in one direction. Donor cell attatches to recipient through the sex pili which requires the F Factor
|
|
F factor as plasmid
|
The f factoris a plasmid, that cell is the F+ cell (donor) and other cell without it is F- (recipient), so that gene signals production of sex pili, and replicates plasmid with f factor and transfers the f plasmid to recipient cell so F- turns to F+, so both F+ now with the f factor
|
|
Factor in chromosome
|
F factor built into chromosome which is donor cell (Hfr/ high frequency recombination-bacterial chromosome) signals for production of sex pili to recipient F- cell. Hfr chromosome gets replicated completely then transfered through sex pili to F- cell then then homologous regions of Hfr chromosome integrate into recipeint chromosome, rest of hfr chromosome disappears, including the F factor so recipient cell is not a recombinant F- bacteria.
|
|
Horizontal/lateral gene transfer
|
movement of genes among individuals from different species instead of vertical which is parents to offspring
|
|
Photoautotrophs
|
get energy from light get carbon from CO2 or HCO3- or other compounds example: photosynthetic proks, plants, some protists |
|
chemoautotrophs
|
energy from chemicals (inorganic chemicals like H2S, NH3, Fe2+) get carbon from CO2, HCO3- example, some proks |
|
Photoheterotophs
|
get enegery from light gen carbon from organic compounds example: aquatic and salt proks |
|
chemoheterotrophs
|
get energy and carbon from organic compounds
example: many proks, protists, fungi, animals, some plants |
|
Obligate aerobes
|
proks that require O2 for metabolism/cellular respiration
|
|
obligate anaerobes
|
proks that are poisoned by O2 and use fermentation or anaerobic respiration for metabolism
|
|
Facultative anaerobes
|
proks that can survive with or without O2 for their metabolism: ex. E coli.
|
|
Nitrogen metabolism
|
some proks can metabolize nitrogen through nitrogen fixation where they convert N2 to NH3. nitrogen essential for amino/nucleid acids |
|
Metabolic cooperation
|
cooperation so proks can use resources they could not use as individual cells example: cyanobacterium anabaena photosyntehic cells and heterocysts (nitrogen fixing cells) exhange metabolic products |
|
Biolfilms
|
where some prok specis form coasts like mushroom and do metabolic cooperation. Starts with some proks/ planktonic on surface then other proks come to form slime then more to form mircrocolony, multiple layers, and then form mushroom shape where some detach and revert to planktonic cells like they started to complete cycle |
|
Chemical recycling
|
proks play role in recylcing of chemical elements between living and non living components of ecosystems, chemoheterotrophic proks function as decomposers, nitrogen fixing proks add usable nitrogen to environment;, proks add nitrogen, phosporus, and potassium for plant growth; proks immobilize or decrease the aviailability of nutrients
|
|
Symbiosis
|
ecological relationship in which two species live in close contact: larger is the host and smaller is the symbiont
|
|
mutualism
|
both symbiotic organisms benefit
|
|
commensalism
|
one organism benefits while neither harming nor helping the other in any significant way
|
|
parasitism
|
an organism called a parasite harms but does not kill its host. parasites that cause disease called pathogens.
|
|
The human microbiome
|
Bacteroides fragilis produces polysacharide A (psa) which helps keep the immune system by boosting anti inflammatory arm. PSA is presented to undifferentiated T cells and stimulates them to become regulatory T cells and tamps down inflammation T cells
|
|
pathogenic bacteria
|
proks cause about half of all human disease, Lyme disease which is cause by bacterium carried by ticks.
|
|
Exotoxins
|
secreted proteins that cause disease even if the bacteria that produced them are not present . proteins in the cytosol of cell and are secreted through wall and membrane(cholera)
|
|
endotoxins
|
released only when bacteria dia and their cell membranes break down; surface associated. the toxins are in the cell wall and are released when dies (salmonella)
|
|
spread of toxin genes
|
through horizontal gene transfer between species
|
|
toxin mechanisms of action
|
damage cell membrane inhibit protein synthesis activate secondary messenger pathways |
|
R plasmids
|
plasmids that carry genes for antibiotic resistance, protects them from antibiotics. through natural selection, the bacteria with resistance increases with exposure to antibiotics.
|
|
Antibiotic resistance
|
starts with a lot of bacteria then exposed to antibiotics which kill bacteria causing illness and protection bacteria. the drug resistant survive then take over and grow. Then drug resistant bacteria spread resistance to other bacteria
|
|
antibiotics resistance spread
|
can spread in the hostpital which goes to other patients or from equipment used and when people go home, they spread. Or eating animals or plants that had antibiotics such as bushmeat
|
|
Methicillin-resistant S aureus (MRSA)
|
staphylococcus aureus contains genes for resistance, ability to colonize host, increased disease severity, and increased gene expression and toxin production
|
|
Bacteria and archaea but not eukarya
|
dont have nuclear envelope, no membrane enclosed organelles, have circular chromosomes, no mitosis, lateral gene transfer, haploid. euks the opposite of this |
|
Archaea and euks but not bacteria
|
no peptidoglycan in cell walls, introns in genes, growth of response to antibiotics not inhibited, histones on dna present. opposite for bacteria
|
|
Bacteria and euks but not archae
|
unbranched hydrocarbons, growth at temperature after >100C., oppositite for archaea |
|
archaea extremes
|
extreme temperatures and pH's
|
|
Eukaryotes
|
most are single celled very complex with functions carried out by organelles have cell membrane and ribosomes like proks but also have dna around proteins, more chromosomes and organelles |
|
Ribosome structure
|
bacteria have no genes around ribosome, ukes have protein rna around it, and mammals have proetin rna, rna-rna and rna
|
|
Endosymbiosis
|
by lynn margulis and this radical concept. it explainsstructure of the complex organelles and nucleus. |
|
hans ris
|
discovered the similarity between chloroplassta nd cyanobacterium. they had ribosomes, similar rna, inner and out membrane, thylakoids, etcs.
|
|
dProk adaptations
|
evolution of photosynthesis 2.7 bya so chloroplasts descend from photosynthetic proks, and there was the oxygen revolution about 2.1 bya and increas use of O2, so mitochondra descend from aerobic heterotrophic proks
|
|
Process of endosymbiosis
|
start with two independent bacteria, then one engulfs the other, one lives inside the other, they benefit from arrangement, internal bacteria are passed on from generation to generation
|
|
Support of endosymbiosis
|
similar inner membrane, division is binary fission, dna short and circular, dna transcribe and translate own dna, ribosimes more similar to proks than euk ribosomes
|
|
Primary vs Secondary endosymbiosis
|
primary is prok doing phagocytosis to another prok, then secondary is when a endosymbiont cell, now a euk is eaten by a prok. this happened when green and red algae were eaten after both had eaten cyanobacteria.
|
|
Chlorarachniophytes
|
enguled cell(prok being eaten by another prok for endosymbiosis) enguled cell became plastid with vestigial nucleus (nucleomorph), the sequence which resemble green algae. 4 membranes: inner an douter from ancient cyanobacterium, 3rd from algae plama membrane and outer from food vaculoe
|
|
Protists
|
everything that is a euk but not fungi, animals or land plants
|
|
History of classifying protists
|
started as one of three domains (plants, protists, animals) then one of five when added fungi and monera. then realized life was more than proks and euks, rather it was tripartite protist before was unicellular euks then term abandoned and just not animals, plants or fungi. protists have more diveristy than other euks |
|
Protists diveristy
|
often parasites
|
|
Giardia
|
parasite in the gut. causes sever diahrea that is in contaminated water or good which infected cysts. treated with metronidazole |
|
Trypanosoma
|
parasitic protist which causes sleeping sickness from kinetoplastids. the host/vector is tsetse fly have the bait and switch defense which is antigenic variation where it changes surface proteins so that way immune system can't bind to it |
|
Plasmodium falciparum
|
parasitic protist that causes malaria. caused by asexual erythrocytic parasites. accumulate in infected red blood cells, dumped into bloodstream when infectd cells lyse
|
|
Process of plasmodium falciparum
|
first mosquito bites and injects sporozoites, then sporozoites enter hepatocytes (liver cells in human). then sporozites form merozoites and those enter red blood cells. Merozoites divide every 2-3 days then break out of rbcs and cause symptoms and infect other rbcs to form gametocytes. another mosquito bites and picks up gametocytes and those gametocyes form male gamets and fertilization occurs in digestive tract of mosquito to form zygote. Then oocyst develops after meiosis from zygote in gut wall and oocyst releases thousands of sporozoites and those migrate to mosquitos salivary glands til it bites another human repeats cycle
|
|
Algae
|
polyphyletic group of photosynthetic eukaryotes
|
|
Dinoflagellates
|
armoured cellulose plates, flagellum lies in groove. blooms cause red tides (harmful algal blooms) produce toxins which can inhibit or kill other phytoplankton(interspecific competition). metabolic pathways responsible for toxin production still under investigation causes organism or paralystic shellfish poisoning (alexandrium catenella), and of diarrhetic shellfish poisoning (dinophysis sp) |
|
Diatoms/pseudo nitzchia and domoic acid
|
neurotoxin that causes amnesic shellfish poisoning--> short term memory loss, seizures, death. biaccumulates in shell fish and fish that feed on toxic phytoplankton... diatomos are unicellular algae with two part glass like wall of hydrated silica, reproduce mostly asexually, major component of phytoplankton, diverse, have diatomaceous earth is fossil walls ***after they die, mayny individuals fal to ocean floor undecomposed |
|
Harmful Algal Blooms (HAB) impact on ecosystem
|
loss of tourism, food sources, ecosystem damage, monitoring, accumulations
|
|
Biological carbon pump
|
during carbon cycle, CO2 naturally removed from atmosphere becase phytoplankton absorb it, and sequester carbo then die and take the CO2 that they sequesterd to bottom of ocean.
|
|
Iron hypothesis
|
by john martin that fertalizing oceans with iron because would increase popoulation of diatoms and would increase carbon sequestratin and used to mitigate global warming
|
|
Slime molds (mycetozoans)
|
once thought to be fungus. have two branches. plamodial slime molds and cellular slime molds
|
|
Plamodial slime molds
|
brightly pigmented yellow or orange. plamodium is undivided by membranes and contains diploid nuclei. extends psuedopodia through decomposing material. engulfs food by phagocytosis
|
|
Cellular slime molds
|
cellular slime molds form multicellular aggregates in which cells are separted by membranes. with food they act individually but without food form aggregates |
|
Dictyostelium discoideum
|
experimental model for studying evolution of multicellularity. very common cellular slime mold
|
|
life cycle of cellular slime mold (dictyostelium)
|
asexual reproduction: solitary amoebas (n)--> aggregated amoebas--> migrating aggregate--> fruiting bodies (n)--> spores (n)--> emerging amoeba(n)--> solitary amoebas(n) Sexual reproduction: solitary amoebas-->fertilization-->zygote(2n)--> meiosis--> amoebas(n)--solitary amoebsa |
|
Obligate cheaters
|
dicty that never form stalk and cheat. may gain reproductive advantage, but they are rare in the wild becasue non cheaters aggregate with other non cheaters, cooperative behavior.
|
|
Primitive farming symbiosis
|
dicty has this where they engage in husbandry and stop feeding early and incorporate bacteria intro fruiting bodies and carry bacteria in spore dispersal. sometimes advantageous other times not. they will reassosciate with bacteria
|
|
fungi
|
diverse and widespread. essential for well being of most terrestial ecosystems because break down organic material and recycle vital nutriets. heterotrophs that feed by absorption. secrete exoenzymes that break down complex molecules and then absorb the smaller compounds |
|
Body structure
|
most are multicellular then single cells (yeasts). morphology of multicellular enhances ability to absorb nutrients. some grow as filaments or yeasts, others do both |
|
hyphae
|
tiny filaments used for absorption |
|
mycelia:
|
networks of branched hyphae adapted for absorption
|
|
chitin
|
what fungi cell walls are made of
|
|
mycorrhizae fungi
|
mutually beneficial relationships between fungi and plant roots. fugni often efficient at absorbing minerals more than roots. increase water uptake and mineral absorptions. plant provides fungus with suppoly of sugar.
|
|
Haustoria
|
specialized hyphae that can extract nutrients from plant cells. remain separated from the plant cells cytoplasm by the plant's plama membrane.
|
|
spores
|
fungi produce these thourhg sexual and asexual processes to propagate themselves.
|
|
plasmogomy
|
union of two parent mycelia, the hyphae are attracted together by signals called pheromones and when they meet they fuse
|
|
heterokaryon
|
when haploid nuclei do not fuse right away and coexist in the mycelium (different nuclie) |
|
dikaryotic
|
when haploid pair off two to a cell dikaryotic meaning two nuclei |
|
Karyogamy
|
nuclear fusion. hours or centuries may occur before karyogamy, the haploid fuse producing diploid cells, this diploid stage is short lived
|
|
sexual reproduction life cycle of fungi
|
mycelium-->plasmogamy--> heterokaryotic stage--> karyogamy-->zygote-->meiosis-->spores--> germination--> more mycelium |
|
asexual cycle of fungi
|
mycelium--> spore producing structures--> spores--> germination--> mycelium
|
|
Diverse lifestyles of fungi
|
--decomposers/saprobes --mutualistic symbionts (metabolic cooperation--mycorrhizae,endophytes, lichens) --Parasites (30% of fungi are parasitic): absorb nutrients from a living host, responsiblefor 80% of plant diseases |
|
Fungi as decomposers
|
efficient decomposers; perform essential recycling of chemical elements between the living and nonliving world -keep ecosystem stocked with the inorganic nutrients for plant growth. plants need fungi for the recycling of these nutrients in the soil. |
|
Mycorrhizae/endophytes
|
myrcorrhizae important in natural ecosystems and agricultures. they harber sybiotic endophyetes that live inside leaves and other plant parts. endophytes make toxins that defend plant against herbivores and pathogens. increase plant tolerance to extremes, increase plant productivity by producing more biomass of individual or community, or increase production of fertility.
|
|
Lichens
|
symbiotic associations of millions of photosynthetic microorganisms held in a mass of fungal hyphae. -photosynthetic organisms can be euk algae or cyanobacteria -fungus give lichen its overall shape and stucuter. tissues of hyphae give it its mass. dual organisms perform asexual reproduction which is common. |
|
types of lichens
|
crustose: important pioneers of new rock, physically and chemically attack rock, trap soil. -lichens predate land plants foliose lichen fruticose lichen. |
|
formation of lichens
|
algae or cyanobacteria occupy inner layer below lichen surface; the algae provide sugar, cyanobacteria fix nitrogen for lichen. fragmentation of soredia |
|
soredia
|
small clusers of hyphase with embedded algae
|
|
history of lichens
|
before 140 years ago, they thought lichens symbiosis between a single fungus and photosynthetic partner. recent research shows that it has second fungus type of yeast unrelated to first fugnus. present in integral parts of lichens.
|
|
Pathogens
|
30% of known fungal species are parasites, mostly on or in plants -some fungi that attack food crops are toxic to humans |
|
ergot of rye (claviceps purpurea)
|
has lysergic acid, causes ergot poisoning the bewitched accusers of salem witch trials may have suffered hallucinations/ skin sensations from crop of fungus infected rye |
|
other plant funguses
|
corn smut on corn (huitlacoches) , tar spot fungus on maple leaves, ergot on rye
|
|
mycosis
|
term for fungal infection in animals; but animals less susceptible to parasitic fungi than are plants
|
|
cordyceps sp.
|
zombie ants have fungus on the brain ants suffer convulsions unable to climb high and stay in cool, damp leaf understory. syncs ant behavior, forcing ants to bite the stem on underside of the leaf at solar noon when sun is strongest. |
|
archaeplastida
|
super group used by some scientists that includes red, green algea and land plants. red and green algae are the closest relatives of land plants.
|
|
Red algae
|
red color due to accessory pigment phycoerythrin that mask green of chlorophyll, green in shallow waters, black very deep. usually multicellular like seaweeds.
|
|
porphyra
|
foliose red alga
|
|
green algae
|
grass green chloroplasts, closely related to land plant, . two main groups called chlorophytes and charophytes
|
|
chlorophytes:
|
unicellular, colonial, and multicellular forms
|
|
similarities between green algae and land plants
|
multicellular, eukaryotic, photosynthetic autotrophs, cellulose cell walls, chloroplasts with chlorophylls a and b
|
|
charophytes
|
similar to plants because have sequence similarities, nuclear and chloroplast gene sequences, charophytes resemble algal ancestors of plants
|
|
why plants above waterline
|
advantages: more sunlight, co2, nutrients. fewer herbivores and parasites disadvantages: scarcity of water, dessiccation, gravity and lack of structural support |
|
derived traits of plants
|
alteration of generations and multicellular, dependent embryos, walled spores produced by sporangia multicellular gametangia, apical maristems |
|
Alteration of generations
|
alternating between haploid and dipoids. plus multicellular, dependent embryos |
|
gametophyte
|
haploid structure taht produces gametes by mitosis
|
|
sporophyte
|
structre that formed from the fusion of gametes, and this produces haploid spores by meiosis
|
|
Diploid embryo
|
retained within tissue of female gametophyte; nutrients are transferred from parent to embyro through transfer cells
|
|
embryophytes
|
land plants; embryo depends on parents
|
|
multicellular gametangia
|
the organ that produces gametes. contains the femal and male gametophytes
|
|
archegonia
|
female gametangia that produces eggs and is the site of fertilization
|
|
antheridia
|
male gametangia that produces and releases sperm
|
|
Sporangia
|
the multicellular organ that sporophytes are located in and that produces spores. within sporangia, diploid cells called sporocytes undergo meisis to make spores. spore walls made out of sporopollenin, help with resistance to harsh envrionments -->helps form walled spores |
|
Apical meristems
|
how plants sustain their continual growth--localized regions of cell division. cells from meristems have different tissues and have specialized functions for above and below ground
|
|
Cuticle
|
covers the epidermis. cuticle consists of wax and other polymers. helps prevents desiccation and resistance to microbial attack |
|
origin and diversification of plants
|
land plants about 475millin years ago as see from fossilized spores and tissues, the sprores were grouped
|
|
vascular tissues
|
origin 425 million years ago
|
|
byrophytes
|
nonvascular plants, not a monophyletic group. the relationships are unresolved
|
|
Seed plants
|
origin 305 million years ago form a clade that can be further divided |
|
seed
|
an embryo and nutrients surrounded by a protective coat
|
|
gymnosperms
|
the naked seed plants, such as conifers
|
|
angiosperms
|
flowering plants
|
|
lifecycles of nonvascular plants including mosses
|
dominated by gametophytes, gametophytes are longer-lived than sporophtes, sporophytes only present part of the time |
|
phyla of bryophytes
|
liverworts (hepatophyta), mosses (bryophyta), hornworts (anthocerophyta), bryophyte and bryophyta are different.
|
|
lifecycle of bryophytes
|
start with spores, then spore buds, then individually in own cycles, form male and female gametophyte (anterhidia and archegonia) then eggs and sperm meet up and fertlizie within archegonium. now diploid, form zygote then embryo, then sporophyte then sporangium givies off haploid spores after meiosis
|
|
importance of mosses
|
sphagnum or peat mosses, forms extensive deposits of partially decayed orangic material called peat, peat is source of fuel sphagnum is importan resovoir of organic carbon and soil carbon, drop in water level in peatlands could release stored CO2 to atmoshere |
|
seedless vascular plants including ferns
|
diversified during the devonian and carboniferous periods, vascular tissue allowed plants to grow tall. have flaggellated sperm that restricts them to moist environements
|
|
life cycle of seedless vascular
|
opposite of bryophytes, the sporophytes is the dominant, larger generation start with spores to gametophyte on or below soil level. with anteridium and archegonium on same structure, sperm reaches egg and fertilizes, forms zygote, new sporophyte that has sporangium and meiosis releases spores. |
|
xylem
|
in vasuclar plants; conducts water and minerals. has dead cells and tracheids lignin that strenthens the water conducting cells and provides structural support |
|
phloem
|
in vascular plantt, disributes organic products and consists of living cells, |
|
roots
|
organs that anchor vascular plants, enable plants to absorb water and nutrients from soil
|
|
significance of seedless vascular platns
|
ancestors of lycophytes, horestails and ferns is that they grew to great heights during devonian and carboniferous period (400-300 million years ago), formed forests increased photosynthesis and removed co2, contributed to global cooling at end of carboniferous period, decaying plants of carboniferous forester turned to coal |
|
seed plants
|
360 million years ago, seed has embryo and nutirents with protective coat. allowed for domestication of plants 8k years ago and permanent settlements
|
|
seeplants adaptations
|
reduced gametophytes, heterospory, ovules, and pollen
|
|
advattages of reduced gametophyte
|
gametophytes are microscopic, gamteophytes develop within walls of spores retained within tissues of the parent sporophyte -protectin from uv rays and desiccation, also get engery from sporophyte |
|
homosporous
|
most seedless vascular plants that produce one type of spore that develops into bisexual gamtertophyte that can develop eggs and sperms
|
|
heterosporous
|
some seedless vascular and alll seed plants that produce megaspores which give rise to femal gametophytes and microspores give rise to male gametophytes, separate sporangiums
|
|
ovules
|
structure that developes within ovary and has female gametophyte, consistes of mega sporangium, mega spore, and protective integuments |
|
integument
|
layer of sporophyte tissue contributes to structre of seed plant
|
|
fertlization
|
the union of haploid gametes to produce dipolid zygotes
|
|
pollen grains
|
microspores develop into this which contain male gametophytes
|
|
pollenation
|
transfer of pollen to part of a seed plant contianing the ovules. eliminates need for film of water and can be dispersed great distances by air or animals. if pollen grain germinates, dives rise to pollen tube that discharges two sperm into femal gametophyte and within ovule
|
|
evolutionary advantages of seeds
|
develop from whole ovule, seed is sporophyte embryo, along with its food supply, packaged in a protective coat, can remain dormant for years till favorable conditions for germination. transported long distance by wind or animals
|
|
gymnosphersm
|
naked seeds such as ones on cones. not enclosed by ovaries and are exposed on modified leaves that form cones. appear 305 million years ago. 4 phyla (cycadophyta, gingkophyta, gentophyta, coniferophyta)
|
|
cydads from cycadophyta phylum
|
flourished in mesozoic era, age of cycads, 300 extant species, unchanged for 300 million years ago
|
|
angiosperm evolution
|
diverege 305 million years ago, originated 140 million years ago. a
|
|
adaptations of angiosperms
|
flowering plants with fruits and flowers. most widespread and diverse. classified under one phylum calls anthophyta
|
|
flower
|
angiosperm structure for sexual reproduction. has specialized shoot with sepals that enclose flower, petals to attract pollinators, stamesn produce pollen with antersn and filamnet and carpels with stigma style and ovary |
|
archaefrutcus sinensis
|
125 million year old chinese angiosperm with anters and seeds but not petals and sepals. had bulbous strucuters
|
|
mimicry
|
when flowers mimic the shape of a bug to attract pollinators to the flower
|
|
orchid mantis
|
pollinator decption, uses mimicry of a flower to attract bugs that it can eat
|
|
fruits
|
help disperse the seeds of angiosperms, consists of mature ovary, seed deelps from ovule and the wall thickens to form fruit, fruit protects the dormant seeds and aid in their dispersal
|
|
evolutionary relation between angiosperms and animals
|
animals influence the evolution of plants and vice versa
|
|
succulence
|
plants ability to store water, can be in specialized stems like cacti or euphorbia, or specialized leaves like aloe or agave
|
|
cacti
|
have spines make of sharp wood outgrowth from leaves. have reduced surface area so dont lose water from transpiration contanct with air. large network of roots |
|
convergent evolution of succulents
|
in america with cacti, euphorbia in africa. have similar desert envvrionments for succeulant traits and distant locations
|
|
lithops
|
plant with each leaf tip that has a region of clear lens like cells that allow light to penetrate to the photosynthetic tissues underground. conserve moisture, hide from grazing tortoises, avoid high temps and light intensities
|
|
|
|