A eukaryote is membrane bound, has compartmentalisation, organelles, and a membrane bound nucleus.
What was the keyto eukaryotic innovation?
The nuclear envelope
What is the Endosymbiosis Theory?
The Endosymbiosis Theory was explored by Lynn Margulis 30+ years ago. The idea she promoted was that the mitochondria was a bacterium that had been incorporated into an ancient eukaryotic history/lineage (Mutualism).
Support for Endosymbiosis
are similar in size to bacteria
reproduce by fission
have own ribosomes
have a double membrane system
Does endosymbiosis explain eukaryotes having chloroplasts too?
1. Not all eukaryotes have them
2. In some groups of photosynthetic protists, there was a secondary endosymbiosis
Where did secondary endosymbiosis first occur?
Secondary endosymbiosis first occured in green algae.
Land plants are important because...
main primary producers
affect atmospheric gases
stabilize soil conditions
moderate local climate
Tradition plant classification
nonvascular, seedless vascular and seed plants
Examples of non vascular plants are:
liverworts, hornworts and mosses
Characteristics of non vascular plants are:
All non-vascular plants have a cuticle
Liverworts have simple pores and protected embryos
Hornworts and Mosses also have stomata
Examples of seedless vascular plants are:
lycophytes, ferns and horsetails
Characteristics of seedless vascular plants are:
All: Trachieds and roots
Lycophytes: addition of vascular tissue
Horsetails and Ferns: true leaves
Examples of seed plants are:
angiosperms and gymnosperms (conifers, cycads, gnetophytesm ginko)
Characteristics of seed plants are:
Benefits of seeds and pollen are:
Can tolerate drying
Seeds are packaged with nutrients
Not dependent on parent during fertilzation
Heterospory: male and female parts/sporophye
Barriers for plants making the move to land were:
water and nutrients equisition and movement
Solution for water loss:
Cuticle: a waxy protective layer
Solution for gas exchange:
First there were pores: openings in the cuticle
Then there were stomata: pores with control (guard cells)
Solution to reproduction barrier:
"Protected embryos": seeds
What is the process of Alternation of Generations:
Start: Gametophyte(multicellular haploid organism) n
Sporophyte(multicellular diploid organism) 2n
End: Mitosis (n)
Solution for water and nutrient equisition and movement:
Vascular tissue: xylem and phloem
Gymnosperms vs. Angiosperms
triploid endosperm (double fertilization:2 male gametes/3 sets of chromosomes)