Evolution And Hominid Studies notes include:
- Development of the theory of evolution
- Evidence of evolution
- Hypothesis vs. theory
- Fundamental aspects of evolution (patterns & trends)
- Evolution by natural selection
- Evolution by other mechanisms
- Artificial selection
- Formation...
Erasmus Darwin
● Life on earth descended from a common ancestor
● Evolution
Jean-Baptise Lamark
● Living species have different fossil types
● Domestication and selective breeding —-→ = change
● Crossbreeding
Suggested traits were passed down
1. Use and disuse of body parts
2. Inheritance of acquired characteristics
Eg. a giraffe stretched neck to eat = long necks
Charles Darwin
Aware of:
● Diversity among organisms
● Variation of individuals
● Distribution of species —-→ 1. Natural selection
● Earth is extremely old 2. Modification with descent
● Great geological change
● Isolation = change
Alfred Russel Wallace
● Shares reputation with Charles Darwin regarding natural selection
EVIDENCE OF EVOLUTION
Fossil records
● Palaeontological evidence
● Detailed information and evidence of change (descent with modification)
● Different rock layers
Eg. modern horse
- Increased complexity → Cambrian explosion
- Increased diversity → old = simple, new = complex/ diverse
- More extinct species → replaced by better-adapted species
- Transitional fossils → eg. mammal-like reptiles
- Increased size
,Cladogram
● Few individuals became fossils
● Hard bodied more likely
● Most are aquatic animals
Biogeography
● Study of where species occur and why
● Different regions with similar climate = different organisms
Evolutionary patterns
1. Clustering pattern of ‘closely allied’ species
● Tortoises of Galapagos
● Zebras in Africa
2. Very different collections of organisms in regions of same latitude
● Old world monkeys/ new world monkeys
● Flightless birds
● Kangaroos/ koala bears
3. Distribution of species on oceanic islands
● Mockingbird distribution → adapted to new conditions = evolution
4. Biogeography of fossils
● Fossils resemble living species from same region
● Ground sloth vs. tree sloth
5. ‘Wallace’s Line’
● Imaginary line bisecting the Malay archipelago into 2 (north western and south eastern)
, Evidence from genetics
● Science of heredity
● Seen through studying DNA and mtDNA
Shows:
1. Organisms have descended from a common ancestor
- All have DNA and RNA
- Many genes with identical proteins
2. Their relation
- Shared sequences of DNA and mtDNA
- More shared = close
Less shared = distant
Eg. humans and chimpanzees
● Rhesus monkey → 1 amino acid
● Horse → 11+ amino acids —→ 103 amino acids in same order
● Tuna → 21+ amino acids
Comparative anatomy evidence
● Comparing external and internal structures
Homologous structures = from common ancestor
= similar structure, position and development
Eg. flippers of whales and legs of horse
Eg. pentadactyl forelimb = divergent and adaptive radiation
Analogous structures = evolved in a similar environment
= same/ similar purposes
Eg. bats and insects
Embryology
● Studying embryos = early stages of development
Vestigial organs
● Structures/ organs stunted with no function
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