ch 29 Flashcards
What are the closest relatives of plants?
Green algae also called charophytes
But how do we know? what evidence do we have of angal ancestry
1) both multicellular
2) eukaryotic
3) photosynthetic autotrophs
4) cell wall made of cellulose
what are Photosynthetic autotrophs
capture light energy from the sun and absorb carbon dioxide and water from their environment.
How did plants migrate from water to land?
Many species of charophyte algae inhabited shallow waters around the edges of ponds and lakes, but then were subject to occasional drying. In such environments, natural selection favoured individual algae that could survive periods when they are not submerged. accumulation of such traits enabled the first plants to live on land
One Key Adaptation for Life on Land?
Sporopellenin:
* Durable polymer that prevents zygote
dehydration in charophytes
* Similar to modern casing of plant spores
what are the advantages of moving onto land?
fewer herbivores, parasites and competitors
increased sunlight
more CO2
rich in mineral nutrients
disadvantages of moving onto land
- gravity- goes against structural support- like a jellyfish
- scarcity of water
- envirnomental fluctuations
How do plants enable other life forms to survive on land
- plants supply oxygen and are a key source of food for terrestrial animals
- sources of medicines and recreationals like caffeine
Overtime, early plants gave rise to a rich diversity of plants, what are the categories?
non vascular plants
Vascular plants: seedless vascular plants and seed plants
seed plants- gymnosperms and angiosperms
What types of land plants are monophyletic
seed plants
How did diversity take place?
several adaptions occured that facilitated survival and reproduction on drylands emerged after plants diverged from algal relatives.
there are 5 main adaptations.
what is the first derived trait and what is it?
Alternation of generations, the alternation between 2 multicellular generations
What are the 2 multicellular generations
1) gametophyte generation ( haploid)
2 sporophyte generation (diploid)
How do spores develop into gametophytes
1) gamete produces haploid gametes by mitosis
2) two gametes unite and form a diploid zygote
3) the zygote develops into a multicellular diploid sporophyte
4) the sporophyte produces unicellular haploid spores by mitosis
5) the spores develop into multicellular haploid gametophytes
what is the 2nd derived trait?
Multicellular, dependent embryos
- the embryo depends on the parent- thus why plants are called embryophytes
what is the 3rd derived trait?
walled spores produced in sporangia
what is sporangia
where the sporophyte produces spores
the sporopollenin of spore walls helps when the organism is in harsh enviornments
what is the 4th derived trait?
multicellular gametangia
gametes are produced in the gametangia
egg is fertilized in the archegonium
what is the 5th derived trait?
apical meristems
have repeated cell division, allowing for continual growth in length by the plant
What do secondary compounds help with
help protect against herbivory parasites and pathogens
Terpenes/terpenaoids are the largest group of secondary metabolities t/f
t
What are shared characteristics of seed plants
1) reduced gametophytes
2) heterosphory ( 2 types of spores)
3) ovules and egg production
4) pollen and sperm production
what are the two types of spores
1) megasporangia - female
2) microsporangia- male
What are angiosperms
seed plants that produce flowers and fruits
