Please enable JavaScript.
Coggle requires JavaScript to display documents.
Chapters 25 & 26 (Chapter 25: The History of Life on Earth (Major…
Chapters 25 & 26
Chapter 25: The History of Life on Earth
Major Events
fossil record: incomplete chronicle of evolutionary change b/c not everything becomes a fossil
radiometric dating: decay of radiometric isotopes, half-life-rate of decay, find ratio of carbon-14 to carbon-12 to determine fossil's age
major events:
Hadean - origin
Archaen - prokaryotes, atmospheric oxygen
Proterozoic - single-celled eukaryotes & multicellular, animals
Paleozoic - colonization of land
Mesozoic - dinosaurs
Cenazoic - humans present
O2 produced during water-splitting step of photosynthesis, it dissolved in water before the concentration was high enough to react with the other elements
endosymbiosis - prokaryotes engulfed a small cell, evolve into mitochomdrian
Cambrian explosion - many present-day phyla appear in fossils from 535-525 mya
colonization of land: vascular systems arose, waterproof root fungi helped to absorb water, arthropods evolved from lobe-finned fish
Eras
4 eras
Paleozoic (541 -252 mya)
Mesozoic (252 - 66 mya) - age of reptiles, terasaur, an extinction
Precambrian (4.5 b - 541 mya) - Hadean, Archaean, Proterozoic, protists
Cenazoic (66 mya - present) - rise of mammals, recent life, warming of earth, rainforests
The Origin of Life
notable contributors
A.I. Oparin & B.S. Haldane - Earth's electron-adding early atmosphere hypothesis, "primitive soup"
Stanley Miller & Harold Urey - early atmosphere experiment
RNA
first genetic material , evidence: also functions as an enzyme-like catalyst, ribozymes, can self-replicate and copy pieces of RNA
natural selection: fastest replicating RNA molecule has most descendant molecules
four stages
macromolecules
protocells
abiotic synthesis
self-replicating molecules
Events
first life: 3.5 bya
first oxygen producers 2.7 bya
first eukaryotic: 2.1 bya
first land-dwellers: 500 mya
Chapter 26: Phylogeny and the Tree of Life
horizontal gene transfer - genes transferred from one genome to another through mechanisms:
exchange of transposable elements and plasmids
viral infections
fusion of organisms
eukaryotes: hybrids
endosymbiosis
transformation
evolutionary relatedness
orthologous genes - homology result of speciation event, occurs between genes found in different species, ex: cytochrome genes in dogs & humans
paralogous genes - homology results from gene duplication, multiple copies of the genes diverged from one another within a species, ex: humans & mice
The Construction of Phylogenic Trees
homology/analogy: indicate whether there is a common ancestor
bioinformatics - biological studies, use computer programming
Classification
order
class
family
phylum
genus
kingdom
domain