plant evolution

Biology V23.0012 with Velhagen at New York University

About this deck

By: Fariya Islam
Textbook:

Biology with MasteringBiology? (with WebCT Access Code Card -- Generic) (8th Edition)
Created: 2011-04-30
Size: 38 flashcards
Views: 7

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cop1 mutation

A. thaliana

recognizes specific protein for degradation

and sends them to proteasome (garbage)

cacao genome

pathway for flavanol biosynthesis (made in chocolate)

cardiovascular health

darwin's abominable mystery

why huge radiation of flowering plants in such short time?

advantages of living on land

- bright sunlight unfiltered by water and plankton

- atmosphere w/CO2

- soil rich in mineral nutrients

- originally few herbivores and pathogens

charophyceans

closest living (extinct) relative to land plants (of green algae)

based on DNA evidence, character traits, fossil spores

live in shallow waters, survive occasional drying, layer of durable polymer (sporopollenin) prevents exposed zygotes from drying out

types of land plants

- mosses, non-vascular

- ferns and allies, vascular

- seed plants

bryophytes

mosses

non-vascular

most closely related to vascular plants

few cells thick

ground hugging carpets

moist environments

derived traits in land plants

absent in green algae (charophyceans)

mosses:

1) alternation of generations

2) multicellular gametangia

3) walled spores produced in sporangia (prevent dessication)

higher plants:

4) multicellular dependent embryos

5) apical meristems

alternation of generations

haploid phase (1N) is multicellular (gametophyte 1N) and unicellular (gamete 1N)

haploid spores can be dominant

and can undergo meiosis

mosses

multicellular haploid gametophyte (1N) dominant

large, multicellular, long lived

sporophyte (2N)

smaller

short lived diploid

dependent on gametophyte

marchantia (liverwort)

gametophytes

multicellular:

archegonium = female (1N)

atheridium = male (1N)

unicellular:

egg (1N)

sperm (1N)

sporopollenin

spore coat

tough, protects against moisture loss

enables spores to be dispersed through dry air

sporangium

haploid

single cell

walled spores (1N)

sporophyte

diploid (2N)

ferns

vascular, seedless

move water/nutrients from roots to leaves

damp environments

flagellated sperm

origins/traits of vascular Ferns

1) vascular system (xylem/phloem)

2) roots (nutrient uptake)

3) leaves (photosynthesis)

4) life cycle w/dominant sporophyte (2N) generation

one model of leaf evolution

adaptation to land = leaves increase surface area for photosynthesis

ferns leave evolution

microphylls (lycophytes) evolved first as outgrowths of stems; supported by single unbranched strands of vascular tissue

megaphylls (have branched vascular systems), evolved by fusion of branched stems --- fuse into leaves

ferns reproduction

sporophytes (2N) of vascular seeds - dominant generation (diploid)

gametophyte (1N) many are tiny free living plants that grow independently on soil

spores -- meiosis -- freeliving/haploid bisexual gametophyte -- antheridium/archegonium -- fertilizes

homosporous spores

ferns

seed vascular plants

sporangium in sporophyll --> single type of spore --> bisexual gametophyte --> eggs/sperm

heterosporous spore production

seed plants

megasporangium in megasporophyll --> megaspore (female spore) --> female gametophyte --> eggs

microsporangium in microsporophyll --> microspore (male spore) --> male gametophyte --> sperm

advantage of seeds

1) after fertilization - ovule becomes seed=embryo, food supply, protective seed coat

2) seed coat protects from desiccation

3) seed dispersal

4) viable embryo-seeds store viable (living but dormant) embryo until appropriate environment for germination

seed parts

fertilization initiates transformation of ovule into seed:

seed coat - 2N, derived from sporophyte integument

food supply - female gametophyte tissue, multicellular

embryo - 2N, new sporophyte

common to all seed plants

1) reduced size of gametophytes (1N)

2) heterospory (male and female spores)

3) ovules & protection of eggs

4) pollen and sperm production

reduced gametophytes (1N) of seed plants are protected in female ovules and male pollen grains

a) moss

b) fern

c) seed plants

a) sporophyte dependent on gametophyte

b) large sporophyte, small independent gametophyte

c) reduced gametophyte dependent sporophyte

multicellular dependent embryos retained in tissues of female parent

zygotes retained in tissues of female parent

for nourishment

gymnosperms history

existed in mesozoic era

age of cycads

dinosaurs

phylum ginkgophyta

1 species: Ginkgophyta biloba

high tolerance to air pollution, popular ornamental tree

female fleshy seeds very purgent

gymnosperms

naked seeds (not enclosed by ovaries) -sporophylls

on leaves, 1 integument surrounding gametophyte (protective tissue layer)

extant (living) species of 4 phyla:

1) cycadophyla (primitive)

2) gingkophyta

3) gnetophyta

4) coniferophyta (pine, fir, redwood)

pine life cycle

from ovule to seed

1) megasporangium (2n) surrounded by integument

2) megaspore develops into multicellular female gametophyte

micropyle (integument opening) allows pollen in
(pollen-male gametophyte, develops into pollen tube, discharges sperm)

3) fertilizat: ovule to seed

features of gymnosperm seed

1) naked seeds not enclosed by ovaries

2) seeds exposed on modified leaves forming cones

features of angiosperm seed

1) enclosed in fruits (mature ovaries)

common features of gymnosperms and angiosperms

1) dominance of sporophyte generation (2N), reduction of gametophyte size (1N)

2) evolution of pollen as airborne agent transferring sperm to ovules

3) development of seeds as resistant and dispersable stage of life cycle (fertilized but dormant embryo)

angiosperm life cycle

double fertilization (pollen tube discharges 2 sperm into female gametophyte w/n ovule)

1 sperm fertilizes egg, 1 combines w/2 nuclei in center cell of female gametophyte and initiates development of food-storing endosperm (nourishes developing embryo)

fruits

mature ovary

carried by wind, water, or animals to new locations, enhancing seed dispersal

identifying genes causing darwin's abominable mystery

1) sequence genes of primitive gymnosperms

2) identify homologs (genes in each species)

3) line up into single sequence (concatenated)

4) aligned based on amino acid sequence

5) construct phylogenetic trees parsimoniously - identify differing genes

phylogenomics of seed plant evolution

identify genes and biological processes that underlie evolution

monochots v. dichots -- over representation in genes making RNAi (red marks)

About this deck

By: Fariya Islam
Textbook:

Biology with MasteringBiology? (with WebCT Access Code Card -- Generic) (8th Edition)
Created: 2011-04-30
Size: 38 flashcards
Views: 7

About StudyBlue

“Simply amazing. The flash cards are smooth, there are many different types of studying tools, and there is a great search engine. I praise you on the awesomeness.”
Dennis