Bio. 230 --- Evolution II. Evolutionary Advances (I) 1) CELL COMPLEXITY Prokaryote ---------->...
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Transcript of Bio. 230 --- Evolution II. Evolutionary Advances (I) 1) CELL COMPLEXITY Prokaryote ---------->...
Bio. 230 --- Evolution II
Evolutionary Advances (I) 1) CELL COMPLEXITY Prokaryote ----------> Eukaryote
2) ORGANISM COMPLEXITY Unicellular ---> Colonial ---> Multicellular
3) ORGANISM SIZE Smaller -------> Larger [?? ---------> Less Large]
4) ORGANISM LIFESPAN Short --------> Longer [?? ----------> Shorter]
5) TYPE OF NUTRITION Heterotrophic ----------> Autotrophic
6) GENOME CONTENT Haploid -------> Diploid
7) TYPE OF NUCLEAR DIVISION PROCESS Mitosis Meiosis (Zygotic, Gametic, Sporic)
Evolutionary Advances (II)
8) TYPE OF LIFE CYCLE Haplobiontic Haploid Diplobiontic Isomorphic Haplobiontic Diploid Diplobiontic Heteromorphic
9) MODE OF REPRODUCTION Asexual --------> Sexual [?? ----------> Asexual]
10) SEXUAL REPRODUCTION AS REGARDS GAMETE DIFFERENTIATION Isogamy --------> Anisogamy --------> Oogamy
11) NUMBER OF OFFSPRING MANY ----------> FEW
12) PROTECTION GIVEN REPRODUCTIVE PROCESS: NONE ----> MUCH
Cell Complexity (I)
Prokaryote to Eukaryote --- 1.5+ byaSerial Endosymbiosis Theory (SET)??? Motility before nucleus ??? (? one origin ?)Nucleus --- endogenous origin in a thermoplasma type archeanMitochondrion --- from an aerobic bacterium (? one origin ?)Chloroplasts --- at least three separate origins
Cell Complexity (II)
Motility StructuresFlagella in prokaryotesFlagella and cilia (? Undulipodia) in eukaryotesNOT the same thing as in prokaryotesWhy use different names?Are undulipodia derived from spirochete bacteria?Did motility (undulipodia) come before the nucleus?
SET (Lynn Margulis)
Primary Endosymbiosis
Secondary Endosymbiosis
Organism Complexity
UnicellularColonialMulticellularAdvantages? SpecializationOrganisms do not always get more complex (e.g. – yeast, some parasites)
Organism Size
Generally smaller to largerBUT sometimes larger to smallerAdvantages of being smaller?Smaller habitats / fewer resources neededShorter life cycle (more chance for genetic change) (? faster evolution ?)
Organism Life SpanGenerally shorter to longerBUT sometimes longer to shorterAdvantages of shorter life span?Reach reproductive maturity soonerGo through more generations in a shorter period of timeThus more chance for genetic change) (? faster evolution ?)
Type of Nutrition
SEE HANDOUT3.5+ bya --- heterotrophic (anaerobic)??? --- anaerobic chemoautotrophs3.0+ bya --- Type I photoautotrophs2.8+ bya --- Type II photoautotrophs??? --- aerobic heterotrophs??? --- aerobic chemoautotrophs
ChemoautotrophismANAEROBIC -- Methanogens -- Domain Archaea
XH + CO2 ---> XCOOH ---> XCHO ----*-----> XCH3 ------#---------> CH3
*Some energy release # methylcobalamin + HSO3(CH2)2SH (X is an unknown carrier molecule)
AEROBIC -– Domain BacteriaNitrosomonas spp. (Nitrifying Bacteria)NH4 + 2O2 -----> 2H2O + NO2
- + energy Nitrobacter spp. (Nitrifying Bacteria)2NO2
- + O2 -----> 2NO3- + energy
Ferrobacillus ferrooxidans (Iron Bacteria)4FeCO3 + O2 + 6H2O -----> Fe(OH)3 + 4CO2 + energy Thiobacillus thioxidans (non-photosynthetic Sulfur Bacteria)2S + 3O2 + 2H2O -----> 2H2SO4 + energy
Photoautotrophism
light
CO2 + 2H2X -------> (CH2O) + H2O + 2X
Type I Photosynthesis (non-oxygenic): light
CO2 + 2H2S -------> (CH2O) + H2O + 2S Type II Photosynthesis (oxygenic): light
CO2 + 2H2O -------> (CH2O) + H2O + O2
Genome Content
Haploid (n) to Diploid (2n)
Terms refer to nuclear content
Advantages of Diploidy?
Type of Nuclear ProcessMitosis (1.5+ bya)What does mitosis do?A ‘conservative’ division
Meiosis (1.2+ bya)What does meiosis do?Sexually reproducing organisms MUST have meiosis somewhere in their life cycle!Meiosis & sexual reproduction make for VARIATION!
Mode of Reproduction
Asexual to sexualBUT, sexual to asexual in some casesAdvantages / disadvantages of sex? Or Why is variation “good” and why is it “bad”?Advantages of haplodiploidy?
Complexity of Life Cycle (I)Haplobiontic Haploid (has zygotic meiosis)
Haplobiontic Diploid (has gametic meiosis)
Diplobiontic (has sporic meiosis) -- isomorphic or heteromorphic -- in heteromorphic either the n or 2n phase can be the dominant one
Haplobiontic Haploid Life Cycle
Haplobiontic Diploid Life Cycle
Diplobiontic Life Cycle
Gamete Differentiation
Isogamy
Anisogamy
Oogamy
Number of Offspring /Protection Given to Reproduction
ManyUsually with little or no care; often with external fertilization
FewUsually with considerable care; usually with internal fertilization