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More Evolution: who, what, how Exam key posted on class webpage Check out Bonuses on class webpage
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O O OOO O O OO OO Bacteria with mutation causing resistance Evolution: changes in DNA as information transmitted Changes to groups, not individuals.
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O O OOO O O OO OO O O OOO O O OO OO O O OOO O O OO OO O Apply antibiotic X XX XXXX X XX Kills most bacteria. Except if some have mutation that allow them to be resistant. Continues to replicate Population of resistant bacteria Bacteria with mutation causing resistance Evolution: changes in DNA as information transmitted Changes to groups, not individuals.
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Evolution: A species’ genetic component changes as the individuals reproduce. These changes are based on how the DNA changes and who reproduces.
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Reproductive success = evolutionary success
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Individuals are selected… But species evolve via changes in DNA during reproduction.
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Who evolves?…Species. A population that can produce fertile offspring A population that does reproduce **A population sharing genetic information** A. harrisi A. leucurus See Section 26.1
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Horse Mule Donkey X =
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Horse Mule (sterile) Donkey X = So…horses and donkeys are not the same species.
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Who evolves?…Species. A population that can produce fertile offspring A population that does reproduce **A population sharing genetic information** A. harrisi A. leucurus See Section 26.1
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How does evolution occur? Fig 24.6
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Divergent Evolution Fig 24.6
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Fig 27.2 Convergent Evolution
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Evolution has no goal...no ultimate life form wrong right Fig 24.15
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Natural Selection: Individuals that are most successful at reproducing will pass on more of their genetic information.
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Natural Selection can only occur when both of these conditions are met: Genetic diversity gives rise to individuals with different traits and Not all individuals can reproduce Fig 24.10
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Variation of a trait within a species
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Three basic types of selection… Directional Stabilizing Disruptive
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Fig 25.3 Directional Selection
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Directional Selection has led to an increase in swallow size after a cold snap Fig 25.3
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Stabilizing Selection Fig 25.4
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Human birth weight has been stably selected Fig 25.4
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Fig 25.5 Disruptive Selection
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Disruptive Selection in blackbellied seedcrackers Fig 25.5
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Disruptive selection can lead to new species, divergent evolution Fig 26.7
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The three different types of selection
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Artificial Selection
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from TeosinteMaize By artificial selection that began ~10,000 years ago. Fig 30.3
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Wild member of Brassica oleracea: small side buds Brussels sprouts: extremely large side buds Artificial selection Number of Individuals Size of buds (cm) 0123 1. Select individuals that have the largest side buds and breed them. 2. Of the offspring, select individuals that have the largest side buds and breed them. 3. Of the offspring, select individuals that have the largest side buds and breed them. 4. After several generations, bud size increases dramatically. Fig 1.3
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Wild Brassica oleracea: small side buds Brussels sprouts: extremely large side buds Artificial selection Number of Individuals Size of buds (cm) 0123 1. Select individuals that have the largest side buds and breed them. 2. Of the offspring, select individuals that have the largest side buds and breed them. 3. Of the offspring, select individuals that have the largest side buds and breed them. 4. After several generations, bud size increases dramatically. Selection only works if there is variability in the population
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Hunter- Gatherer Agricultural Industrial Artificial Selection (breeding)
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Modern cows were bred from earlier bovine species.
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Different foods from one species of plant. Created by artificial selection.
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Evolution: A species’ genetic component changes as the individuals reproduce due to… Non-random changes (natural selection) Random changes (genetic drift/bottleneck) Mutations add new alleles or genes
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Next even more Evolution: the environment and randomness Exam key posted on class webpage Check out Bonuses on class webpage
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