Transcript Chapter 26 (Sep 14-15)

Ch 26: The Tree of Life-An Intro to Biological Diversity
1. What do you know about the origins of life on Earth?
- Earth is 4.6 billion yrs old (byo)
- Oldest rocks – 3.8 byo
- Oldest fossils – 3.5 byo
2. How was primitive Earth different than current Earth?
- Little O2, much H2O, CH4, CO, CO2
- Lightning
- Volcanic activity
- UV radiation
- Meteorite bombardment
3. How do we get “the living” from “the non-living?”
- 1920’s Oparin & Haldane postulated early Earth favored rxns that
formed organic cmpds from inorganic cmpds
- 1953 Miller-Urey experiment test Oparin & Haldane’s hypothesis
Figure 26.2 Can organic molecules form in a reducing atmosphere?
Repeated experiments have formed
- All 20 amino acids
- several sugars
- lipids
- purines & pyrimindines
- ATP (when phosphate is added)
- ALL MONOMERS
Ch 26: The Tree of Life-An Intro to Biological Diversity
1. What do you know about the origins of life on Earth?
2. How was primitive Earth different than current Earth?
3. How do we get “the living” from “the non-living?”
- 1920’s Oparin & Haldane postulated early Earth favored rxns that
formed organic cmpds from inorganic cmpds
- 1953 Miller-Urey experiment test Oparin& Haldane’s hypothesis
4. How were monomers connected to make polymers?
- Sydney Fox dripped monomers on hot sand, clay or rocks
- Created proteinoids – polypeptides created by abiotic means
5. What’s next?
- Protobionts – abiotically produced molecules surrounded by a
membrane
- Primitive cells
- Imprecise reproduction
- Simple metabolism & excitability
6. How does natural selection fit in?
- Protobionts best suited to their environment could reproduce & create
others best suited to their environment
Figure 26.4 Laboratory versions of protobionts
Glucose-phosphate
20 m
Glucose-phosphate
Phosphorylase
Starch
Amylase
Phosphate
Maltose
Maltose
(a) Simple reproduction. This liposome is “giving birth” to smaller
liposomes (LM).
(b) Simple metabolism. If enzymes—in this case,
phosphorylase and amylase—are included in the
solution from which the droplets self-assemble,
some liposomes can carry out simple metabolic
reactions and export the products.
Ch 26: The Tree of Life-An Intro to Biological Diversity
1.
2.
3.
4.
5.
What do you know about the origins of life on Earth?
How was primitive Earth different than current Earth?
How do we get “the living” from “the non-living?”
How were monomers connected to make polymers?
What’s next?
- Protobionts – abiotically produced molecules surrounded by a
membrane
- Primitive cells
- Imprecise reproduction
- Simple metabolism & excitability (similar to neurons)
6. How does natural selection fit in?
- Protobionts best suited to their environment could reproduce & create
others best suited to their environment
7. What was the first genetic material?
- RNA – single stranded
- Ribozymes – can replicate RNA
Figure 26.5 A ribozyme capable of replicating RNA
Ribozyme
(RNA molecule)
3
Template
Nucleotides
Complementary RNA copy
5
5
Ch 26: The Tree of Life-An Intro to Biological Diversity
1.
2.
3.
4.
5.
What do you know about the origins of life on Earth?
How was primitive Earth different than current Earth?
How do we get “the living” from “the non-living?”
How were monomers connected to make polymers?
What’s next?
- Protobionts – abiotically produced molecules surrounded by a
membrane
- Primitive cells
- Imprecise reproduction
- Simple metabolism & excitability (similar to neurons)
6. How does natural selection fit in?
- Protobionts best suited to their environment could reproduce & create
others best suited to their environment
7. What was the first genetic material?
- RNA – single stranded
- Ribozymes – can replicate RNA
8. Natural selection over millions of years
- led to a diversity of the 1st prokaryotes
- then…prokaryotes  eukaryotes (ENDOSYMBIOTIC THEORY)
Endosymbiotic Theory
Domain Archaea
Domain Bacteria
Universal ancestor
Domain Eukarya
Charophyceans
Chlorophytes
Red algae
Cercozoans, radiolarians
Stramenopiles (water molds, diatoms, golden algae, brown algae)
Chapter 27
Alveolates (dinoflagellates, apicomplexans, ciliates)
Euglenozoans
Diplomonads, parabasalids
Euryarchaeotes, crenarchaeotes, nanoarchaeotes
Korarchaeotes
Gram-positive bacteria
Cyanobacteria
Spirochetes
Chlamydias
Proteobacteria
Figure 26.22 One current view of biological diversity
Chapter 28
Plants
Fungi
Animals
Bilaterally symmetrical animals (annelis,
arthropods, molluscs, echinoderms, vertebrate)
Cnidarians (jellies, coral)
Chapter 32
Sponges
Chapter 31
Choanoflagellates
Club fungi
Sac fungi
Chapter 28
Arbuscular mycorrhizal fungi
Zygote fungi
Chytrids
Chapter 30
Amoebozoans (amoebas, slime molds)
Angiosperms
Gymnosperms
Seedless vascular plants (ferns)
Bryophytes (mosses, liverworts, hornworts)
Chapter 29
Chapters 33, 34