Lecture 1- Plants and the Colonization of Land Flashcards
What is the importance of plants
- Agriculture
- Conversion of the sun’s energy
- Energy in the form of fossil fuels
- Clothing
- Drugs, medicines
- Ecosystem functioning
- Biodiversity
What is the basis of energy
Plants
Secondary compound
- Protect plants from predators
- Poison that wards off potential predators from consuming plant
- Found in many drugs like caffeine or marijuana
Botany
- the study of plants
- also called plant science
How does pollination work?
1) Bee probes into flowers and obtains nectar
2) Flower puts pollen (sperm) on bee
3) Bee travels to other flowers and cross fertilizes
Pollination of the Cardinal Flower by the Hummingbird
The Cardinal flower needs the hummingbird to pollinate
- Each flower is initially female, and then transitions to be male
- Hummingbird does not move enough pollen around, all flowers are competing and have specific adaptions because of this.
- Some flowers taller than others, etc
Flower is in either:
Male phase: produces pollen, top of plant
Female phase: receives pollen, bottom of plant
Formation of Plants and red algae (Plastids)
- Plastids first appeared when a eukaryote engulfed a cyanobacterium, giving rise to the red algae, green algae, and land plants
- Resulted formation of chloroplast
Plants defined
- Include chlorophytes, charophytes, and embryophytes
- Photosynthesis occurs in all of these
Chlorophytes
green algae
Charophytes
green algae
Embryophytes
land plants
Why does photosynthesis occur in plants and red algae
From primary endosymbiosis
Primary endosymbiosis
- A non-photosynthetic eukaryote engulfed a photosynthetic prokaryote (cyanobacterium/plastid) allowing photosynthesis to arise
- Prokaryote + eukaryote = eukaryote
Why does photosynthesis occur in other eukaryotes (strange names)
From secondary endosymbiosis
Secondary endosymbiosis
- Non-photosynthetic eukaryote engulfs the photosynthetic eukaryote produced by primary endosymbiosis (green or red algae)
- Eukaryote + eukaryote
Plants split from the red algae approximately
1500 my (1.5 by)
The Oxygen Revolution
Cyanobacteria constantly produced oxygen during photosynthesis, increasing the amount of O2 in the atmosphere and setting it off balance. Increased levels of O2 is toxic to certain organisms, resulting in one of the Earth’s most significant mass extinctions.
Major Events in the History of Plant Life
4550 MY- Earth forms
3500 MY- Photosynthesis appears (cyanobacteria)
1500 MY- 1st Plastid, Plants and red algae diverge
(when plants were invented)
700 MY- Further oxygen increase
Features of All Plants: Chlorophytes, Charophytes, and Embryophytes
1) Starch is the main energy source and storage molecule for plants
2) Contain Chlorophyll b
3) Cellulose in cell walls
4) Stacked thylakoids (“grana”)
Starch
- Polysaccharide of glucose residues
- Made up of two polysaccharides: amylose and amylopectin
Amylose
- Makes up 20% of starch
- unbranched