ProfessorJean Jiang Nash
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Chapter 4: The Geography of Life
Evolution explains the distribution of life across the earth. Oceanic islands tend to have
unbalanced and odd fauna and flora. Darwin: distribution of species = after dispersal,
evolution of new species + shifting earth. Molecular taxonomy and continental drift explains
Creationist cannot explain why different types of animals have similar forms in different
EVOLUTION: CONVERGENT EVOLUTION. Species in similar habitats will experience
similar selection pressures from the environment so they may evolve similar adaptations
(converge), coming to look alike despite the fact that they are very much unrelated. (i.e.
similar colors of artic animals, cacti and euphorbs-deserts)
Convergent evolution demonstrates: 1) COMMON ANCESTRY 2) SPECIATION 3)
Also continental driftglossopterisbiology indicates cold climate plant but found in
warm weather. Seed cannot migrate because heavy:: actually due to continents moving
(including trees themselves).
Continental islands-once connected to continents; Oceanic islands – never connectedfrom
volcanoes or coral reefs
Oceanic islands lack native species found in many continents and continental islands. Most
oceanic islands lack the SAME MISSING GROUPS, but have their own endemic organism.
When humans introduce species to oceanic islands, they tend to do well and destroy
Oceanic islands have similar species. One group is overrepresented, with species filling
niches occupied by very different species on continents or continental islands.
UNBALANCED BIOTAS (missing major groups of organism). Oceanic islands usually have:
plants, bird and insects and are missing reptiles, amphibians, land mammals and
freshwater fishes. Former group of species can go through long-distance dispersal.
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