M2 - Plants Flashcards
What is FECA
First Eukaryotic Common Ancestor
What is LECA
Last Eukaryotic Common Ancestor
Are algae a monophyletic group
Nope, they are a diverse photosynthetic organism living in water
What are Archaeplastida
Algae and land plants
Are land plants a monophyletic group
Yes
What are synapomorphies of plants
- Chloroplasts
- Photosynthesis
- Cell Walls
What are chloroplasts
Photosynthetic bacteria that were engulfed into eukaryotic cells during primary endosymbiosis
What does photosynthesis do
Convert sunlight, carbon dioxide and water into sugars to fuel a plant
What are cell walls made out of
Carbohydrates and other molecules
What do land plants have in cell walls
Cellulose
What caused aquatic plants to transition to landplants
The late Devonian extinction causing reduced CO2 levels and global cooling
What was the issues with transitioning from aquatic to land plants (2)
- Gravity
- Dehydration
What were the key adaptions to allow the transition to land plants (4) (AKA synapomorphies of land plants)
- Cellulose cell walls
- Cuticles
- Stomata
- Embryo retention
How did cellulose cell walls help plants adapt to land
Made walls more rigid allowing them to grow upright without buoyancy
How did cuticles help plants adapt to land
They are a waxy layer that prevented dehydration in plants by reducing water loss
How did stomata help plants adapt to land
Allowed for gas exchange - opened for CO2 uptake and closed to prevent water loss
How did embryo retention help plants adapt to land
- Allowed for protection of embryos during development
What are the stages of land plants (2)
- Gametophytes
- Sporphites
Have do gametophytes reproduce
Produce gametes by mitosis
How do sporphites reproduce
Produce spores through meisosis
What are the 2 types of land plants
- Bryophytes
- Vascular plants
Describe the characteristics of bryophytes
- Non vascular plants
- Small
- Reproduce in wet conditions
What are examples of bryophytes
Liverworts, hornworts, mosses
What stage do bryophytes spend most of their time in
Gametophyte (n) stage is dominant
Sporophytes (2n) on plants are small
