Bio 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 bya  Serial Endosymbiosis Theory (SET)  ??? Motility before nucleus ??? (? one origin ?)  Nucleus --- endogenous origin in a thermoplasma type archean  Mitochondrion --- from an aerobic bacterium (? one origin ?)  Chloroplasts --- at least three separate origins

Cell Complexity ( II )  Motility Structures  Flagella in prokaryotes  Flagella and cilia (? Undulipodia) in eukaryotes  NOT the same thing as in prokaryotes  Why 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  Unicellular  Colonial  Multicellular  Advantages? Specialization  Organisms do not always get more complex (e.g. – yeast, some parasites)

Organism Size  Generally smaller to larger  BUT sometimes larger to smaller  Advantages of being smaller?  Smaller habitats / fewer resources needed  Shorter life cycle (more chance for genetic change) (? faster evolution ?)

Organism Life Span  Generally shorter to longer  BUT sometimes longer to shorter  Advantages of shorter life span?  Reach reproductive maturity sooner  Go through more generations in a shorter period of time  Thus more chance for genetic change) (? faster evolution ?)

Type of Nutrition  SEE HANDOUT  3.5+ bya --- heterotrophic (anaerobic)  ??? --- anaerobic chemoautotrophs  3.0+ bya --- Type I photoautotrophs  2.8+ bya --- Type II photoautotrophs  ??? --- aerobic heterotrophs  ??? --- aerobic chemoautotrophs

Chemoautotrophism ANAEROBIC -- Methanogens -- Domain Archaea XH + CO 2 ---> XCOOH ---> XCHO ----*-----> XCH # > CH 3 *Some energy release # methylcobalamin + HSO 3 (CH 2 ) 2 SH (X is an unknown carrier molecule) AEROBIC -– Domain Bacteria Nitrosomonas spp. (Nitrifying Bacteria) NH 4 + 2O > 2H 2 O + NO energy Nitrobacter spp. (Nitrifying Bacteria) 2NO O > 2NO energy Ferrobacillus ferrooxidans (Iron Bacteria) 4FeCO 3 + O 2 + 6H 2 O -----> Fe(OH) 3 + 4CO 2 + energy Thiobacillus thioxidans (non-photosynthetic Sulfur Bacteria) 2S + 3O 2 + 2H 2 O -----> 2H 2 SO 4 + energy

Photoautotrophism light CO 2 + 2H 2 X > (CH 2 O) + H 2 O + 2X Type I Photosynthesis (non-oxygenic): light CO 2 + 2H 2 S > (CH 2 O) + H 2 O + 2S Type II Photosynthesis (oxygenic): light CO 2 + 2H 2 O > (CH 2 O) + H 2 O + O 2

Genome Content  Haploid (n) to Diploid (2n)  Terms refer to nuclear content  Advantages of Diploidy?

Type of Nuclear Process  Mitosis (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 sexual  BUT, sexual to asexual in some cases  Advantages / 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  Many  Usually with little or no care; often with external fertilization  Few  Usually with considerable care; usually with internal fertilization