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Week IV: Structure, Development and Interaction of Animal - Coggle Diagram
Week IV: Structure, Development and Interaction of Animal
Principle of classification
Homology
ancestor had the same feature
inherited from common ancestor
divided
structural homology
structures have exactly same, but same function
developmental homology
developments same of embryos
molecular homology
gene same in structure and evolutionary origin
different species because they come from common ancestor
eg: :bear: (forelimb), :bird: (wing) and human (arm) same functional types of bones
homologous structure of bones :green_book:
Parallelism
ancestor had initial feature that led to later similarity
non homologous structural similar
common ancestor didn't have same anatomical structures
similarity due to independent development along evolutionary lineage.
homoplasies structures :blue_book:
shared character between 2 @ more animal not arise from common ancestor
opposite homology :green_book: :vs: :blue_book:
eg: South American & African :monkey: evolved relatively large body sizes independently.
their common ancestor much smaller
Convergence
more distance common ancestor
homoplasies structures :blue_book:
@ convergence evolution
similar anatomical feature in distinct species lines after divergence from common ancestor
due to natural selection pressure over time
eg: Australian Tasmanian (marsupial) :wolf: :vs: :wolf: North American (placental mammal)
Analogy
no known common ancestor
homoplasies structures :blue_book:
same function in different species with no common ancestor
eg: wing :bird: & :butterfly: similar shape and function, different :bird: wings consist of bones, :butterfly: wings do not have bones
Dilemma
What?
listing characteristic making it appear fixed and external which is not.
dynamic continuous changing
arbitrarily define along evolutionary line
determining specific characteristic that distinguish newly discovered animal.
which trait (feature) is the most important
Solution?
splitter approch
based on minor differences
lumper approach
ignore minor differences
emphasis major similarities
breeding experiment
difficulties (time consuming & animal not cooperate)
fossil record impossible
somehow closely related species produce a fertile offspring in very small fraction
