Upload
aron-quinn
View
213
Download
0
Tags:
Embed Size (px)
Citation preview
Ch. 22 Warm-Up1. Compare and contrast natural selection
vs. artificial selection.2. What are the key ideas of natural
selection?3. Define and give an example for the
following:Homologous structureVestigial structureAnalogous structure
Descent with Modification:
A Darwinian View of Life
Part B: Evidence for Evolution
Recap main ideas of natural selection:1. Evolution is change in species over time.2. There is overproduction of offspring, which
leads to competition for resources.3. Heritable variations exist within a population.4. These variations can result in differential
reproductive success.5. Over generations, this can result in changes in
the genetic composition of the population.
Remember:Individuals do NOT evolve! Populations
evolve.
Evidence for Evolution:1. Direct Observations2. Fossil Record3. Homology4. Biogeography
Evidence for Evolution1. Direct Observations
2. Fossil Record
3. Homology 4. Biogeography
Evidence for Evolution:1. Direct ObservationsExamples:Insect populations become resistant to pesticides (DDT)Antibiotic-resistant bacteria (MRSA)Peppered moth (pollution in city vs. country)
Evidence for Evolution:2. Fossil RecordFossils = remains or traces of organisms
from pastFound in sedimentary rockPaleontology: study of fossilsShow evolutionary changes that occur over
time and origin of major new groups of organisms
Prokaryotes (oldest fossils) eukaryotes (fish – amphibians – reptiles – birds – mammals)
Transitional forms = links to modern species
Evidence for Evolution:3. HomologyHomology: characteristics in related species can have
underlying similarity even though functions may differExamples:
Homologous structures: similar anatomy from common ancestors (eg. forelimbs of human/cat/whale/bat)
Embryonic homologies: similar early development (eg. vertebrate embryos with tail & pharyngeal pouches)
Vestigial organs: structures w/little or no use (eg. flightless bird wings)
Molecular homologies: similar DNA and amino acid sequences
Molecular HomologiesCompare DNA and
amino acid sequences
Convergent EvolutionDistantly related species can resemble one
anotherSimilar problem, similar solutions!Analogous structures: similar structures,
function in similar environmentsEg. Torpedo shape of shark, penguin, &
dolphin
Evidence for Evolution:4. BiogeographyBiogeography = geographic distribution
of a speciesSpecies in nearby geographic areas
resemble each otherContinental drift and Pangaea explains
similarities on different continentsEndemic species: found at a certain
geographic location and nowhere elseEg. Marine iguanas in the Galapagos