BIOLOGY 1B Lecture Notes - Lecture 30: Gnetophyta, Archaefructus, Nitella
Review
First Unit
- Stromatolites → microorganisms → prokaryotes → building communal structures →
stromatolites TODAY are not all prokaryotic, some are eukaryotic → stromatolite =
biofilm
- Cyanobacteria → responsible for ozone layer and oxygenated atmosphere → responsible
for early earth
Second Unit
- Serial endosymbiosis → life folding on itself
- Single celled ancestor to stramenopiles
- Unicellular cannot be haplodiplontic
- Independent evolution → convergence → haplodiplontic evolved on certain
branch
Third Unit
- Glaucophyta → basal archaeplastida → they have peptidoglycan in their chloroplasts
- Shows endosymbiotic history with cyanobacteria
- Red algae → can occur at significant depths → can still photosynthesis → often look
black
- Green algae includes chlorophytes and charophytes
- Chlorophytes → ulva, volvox
- Chlamydomonas → red snow
- Beatrix Potter → suggested lichen is a symbiosis of fungi and algae
- Charophytes → connection between water and land
- They have sporopollenin that protect them from desiccation and UV radiation
- Nitella has a haplontic life cycle
- Bryophytes
- Mosses, liverworts, hornworts
- Non-vascular
- Multicellular gametangia → embryos will develop with some kind of protection
- Stomata
- Tracheophytes → vascular plants
- Lycophytes → has vascular systems (first of tracheaphytes)
- Ferns
- 3 types
- Appear after burns
- Life cycle shows independence of sporophyte and gametophyte stage
- Haplodiplontic
- Gametophyte becomes small and irrelevant, sporophyte becomes dominant
- Sori
Document Summary
Stromatolites microorganisms prokaryotes building communal structures stromatolites today are not all prokaryotic, some are eukaryotic stromatolite = biofilm. Cyanobacteria responsible for ozone layer and oxygenated atmosphere responsible for early earth. Independent evolution convergence haplodiplontic evolved on certain branch. Glaucophyta basal archaeplastida they have peptidoglycan in their chloroplasts. Red algae can occur at significant depths can still photosynthesis often look black. Beatrix potter suggested lichen is a symbiosis of fungi and algae. Charophytes connection between water and land. They have sporopollenin that protect them from desiccation and uv radiation. Multicellular gametangia embryos will develop with some kind of protection. Lycophytes has vascular systems (first of tracheaphytes) Life cycle shows independence of sporophyte and gametophyte stage. Gametophyte becomes small and irrelevant, sporophyte becomes dominant. Cycadophyta look like tree ferns produce strobili. Cycads are neither tree ferns nor palm trees. Xylem has tracheids and vessels moves lots of fluid rapidly. Xylem is dead but phloem is alive.
