Theme 3 Flashcards
Coevolution and Animal Pollinators
occurs when two or more species interact closely in the same ecological setting
- heritable change in one affects the other
plants and animals have evolved for pollination
What makes the largest identified group
plants
Multiple challenges on land
- desiccation: protection from drying out
- respiration: structures to breathe
- reproductive: learn how to become successfull reproducers under desiccating conditions (pollen, ovule, pollen tube)
- locomotion: movement structures
- senses: changes in light, sound, and smell
75% of land animals:
anthropods
Why do we need plants
ecosystem services
oxygen
drugs
food, fiber, timber
Order of green plants (bottom to top inverted triangle)
green plants (green algae)
non-vascular (
seedless vascular (
seed (gymno- angio sperms)
Traits for [blank] = number 1 adaptation
desiccation
Morphological adaptations to dry conditions on land
waxy cuticles (protection from rying out & pathogen attack)
stomata (pores for gas exchange - controlled by special cells called GAURd cells)
- earliest found in non-vascular plants (moss)
- turgid vs. flaccid
vascular system/tissue (cells for transpot of water & structural support/rigidity)
- all cell walls with lignin (secondary cell walls) - effective in resisting gravity
- vessels = angiosperm
- tracheid = xylem
root system (absorption of water)
- evolved from belowground parts of ancient vascular plants
- nonvascular plants (moss) – rhizoids
(fern gametophytes are used for rhizoids
page 17 - know highlighted info
Turgid
open
Flaccid
open
drough
closed
What are the order of traits
cuticle - stomata - vascular tissue - roots - trachoids
page 20
Reproductive adaptation on dry conditions (land)
plants
for algae, all reprod was water-mediate
- alternation of generations (gametophyte and sporophyte)
- embryo was retained and nourished by the parent (kinda like pregnancy in mammals)
- adaptive strategy to protect the gametes and embryo in a non-aquatic environment
Alternation of generations
in terms of reprod. change for dry conditions
plant life cycle alternates between haploid (gameto) and diploid (sporo) gen.
Haploid: n
Gametophyte: makes gametes
diploid: 2n
Sporophyte: goes thru meiosis to make spores instead of gametes; spores under favourable conditions grow into gametophytes
- as plants become evolutionary advanced, gametophytes (n) generation was severely reduced with the sporophyte (2n) gen becoming dominant
How is the life cycle for these plants different than animals
one free living diploid individual
- gametes (n) are formed through meiosis
- gametes are not free living
page 23
Alternation of generations adaptation - change in cycle
page 24 - bottom half is gone
Alternation of generation in the algal ancestor of land plants
- long gametophyte phase
- zygote undergoes meiosis to produce spores
- haploid spores give rise to gametopytes that make haploid gametes through mitosis
- zygote represents only diploid stage
page 25
PAGE 26 - HAS dIFF ALTERNATION OF GEN CYCLES FOR ALGAE, MOSS, FERN, CONIFER
legnth of gametophyte gen goes from long to short in that order of evolution
water availability went from high to low
- free living zygote was only in algae
- in true land plants, zygote is attached to female gametopyte
KNOW TRIANGLE GRAPHS FOR WATER AVAIL. ANd LENGTH OF GAMETOPHYTE
Graph trend for the following:
1. length of sporophyte
2. relatvie size of gametophyte
3. relative size of sporophyte
4. protection of zygote/embryo*
*remember for sure
- short to long
- large to small
- small to large
- low to high*
Phyla tree on page 28
Evolutionary trend from haploid to diploid
8 nuclei -> 7 cells
check slide 29
- diploid got bigger (development of flowers)
- haploid got smaller (development of seeds)
What three things are all extremely adapted to dry conditions and wait for favourable growth conditions?
spores, pollen grains, and seeds
What did alternation of generation allow?
plants to be more successfull
AG adaptions are riven by what?
scarcity of water
Plants have evolved to maintain what? as the dominant phase of AG
diploid state
