Plants Flashcards
What was the origin of photosynthesis?
- cyanobacteria - global game changers
- developed multicellurity and cell specialization
- “Great oxidation event” oxygen in earth atmosphere, complex life possible
Explain endosymbiosis (include primary and secondary)
It is the origin of chloroplasts. Originated when ‘protist’ engulfed a cyanobacterium. Primary endosymbiosis is when it is engulfed and then has 2 membranes. Then secondary endosymbiosis. 1) the photosynthetic protist is engulfed, the nucleus is lost, and the organelle now have 4 membranes.
What are some photosynthesized that make a lot of oxygen?
- Trees
- Plants
- Eukaryote photosynthesizers
Phytoplankton
- Single celled
- Marine environments
- 50% of global photosynthesis
- made up of: photosynthetic bacteria (cyanobacteria) and diatoms (single celled photosynthetic eukaryotes)
Brown Algae
- chloroplast w/ 4 membranes
- multicellular
- brown colour - carotenoid pigment fucoxanthin
What has the fastest growth rate of any seaweed and is a keystone species?
Kelp!
Alternation of generations
- type of life cycle for some plants and algae
- alternates between gametophyte form and sporophyte form
Gameotophyte vs sporophyte
Gameotophyte= multicellular haploid (n) form (made by mitosis) Sporophyte= (2n) diploid, produce spores by meiosis
What are spores?
Single (n) cells that grow without fertilization
Red Algae
- uni and multicellular
- red colour from carotenoid pigment phycoexythin
- coraline red algae = helps build coral reefs, attract coral larvae, patch things up like bandaid
What is a non-vascular plant?
It means that it does not flower
Viridiplantae
“green plant”
monophyletic group
green algae (in water) (uni and multi cellular)
land plants are major photosynthesizers
Define byrophytes
non-vascular plant
define tracheophytes
vascular plant
Describe the transition to land plants
Green plants (algae) -> land plants (non-vascular) -> vascular plants (seedless) -> gymnosperms (seed plants)
Name some advantages and disadvantages to plants moving onto land
Advantages: - Huge uncolonized area - light - C02 - less herbivory Disadvantages: - UV radiation - Dehydration - Dispersal - Gravity - Nutrients
How did plants survive in the sun after they transitions to land?
They made compounds that absorbs UV light
Define a Cuticle (key innovation)
- prevents water-loss but inhibits gas exchange
- watertight covering above ground land plants
- made up of hydrocarbons, lipids and wax produced by epidermal cells
What are the 3 innovations for plants to reproduce on land? Tell me about them.
1) Spores: tough coat, resist drying, dispersed hundreds of km by wind
2) Gametes: specialized reproductive organs that all modern land plants have but angiosperms. Either male or female.
3) Embryos nourished by parent plant. retain the eggs now, they do not shed in water or soil.
Byrophytes
Mosses, liverwortes, non vascular
No vascular tissue, no true roots, absorb nutrients and water through “leaves”, small (slow growing), lived in damp habitats.