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+ 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 + CO2 ---> XCOOH ---> XCHO ----*-----> XCH3 ------#---------> CH3
*Some energy release
# methylcobalamin + HSO3(CH2)2SH
(X is an unknown carrier molecule)
AEROBIC -– Domain Bacteria
Nitrosomonas 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 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