Plants and their cell components Flashcards
Evolution
Is a change in the heritable characteristics of a population over generations, or the process of diversification by which new species or populations develop from pre-existing forms
Darwin
“descent with modification”
* Species are descended from a common ancestor
* Species change over time
Population Genetics
A change in population allele frequencies over time
* “modification” is the result of genetic changes
Phylogeny
A hypothesis of ancestor-descendent relationships
Nodes
Represent common ancestors
Tips
Represent the descendants of that ancestor
Roots
As we move from root to tip we are moving forward in time
Anchor the plant and collect water
Vascular Tissues
They transport water and nutrients upward from the soil to leaves, where photosynthesis takes place
Vascular plants
Plants with plumbing
Synapomorphy
- Shared derived trait
A characteristic present in an ancestral species and shared exclusively (in more or less modified form) by its evolutionary descendants
Synapomorphy in plants
Tracheids
Vascular tissue
Xylem
Phloem
Tracheids
Elongated cells that transport water and mineral salts through the Xylem of vascular plants
Xylem
Transports water through the plant
Phloem
- Living vascular tissue that carries sugar and organic substances throughout a plant
- Organic compounds (made from photosynthesis)
When were xylem first present in fossil records
mid-silurian
The first seed trees
- Mature trees with good genetic characteristics and high seed production
- Evolved for the first time at the end of the Devonian period.
- The earliest member of the lignophyte clade
Progymnosperms
- Extinct seedless vascular plants that may be ancestral to seed plants
Lignophytes
Woody plants
Ethnobiology
The study of how traditional cultures classify objects and organisms in the natural world
Cereal grain
Fruits of grasses (monocots) that can be gathered or cultivated as a food for humans
Human civilization was founded on cereal grains
What are plants?
Plants produce oxygen while packaging the sun’s energy into compounds needed for life. They make up more than 80% of the total biomass on earth
Bacterial cell walls
Composed of peptidoglycan, a complex of protein and sugar
Archaeal cell walls
Composed of polysaccharides (sugars)
Eukaryotic cell walls
Found in plants are composed of cellulose, and the cell walls of fungi are composed of chitin
Archaeplastida super-groups
Consists of three major groups:
- Viridiplantae (green algae and plants)
- Red algae (Rhodophyta)
- Glaucocystophytes (glaucophyta)
Species scape
Each organism’s size is proportional to the number of species in that group
Cavitation
When an air bubble enters the xylem
The Great Oxidation Event
The time in Earth’s history, about 2.4 Ga, when the concentration of oxygen in the atmosphere increased dramatically.
Cyanobacteria
Were responsible for the Great Oxidation Event (or the “rusting” of the Earth)
They introduced oxygen into the atmosphere
Are oxygenic phototrophs