Semester 2, Day 11 Other Mechanisms of Evolution.
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Transcript of Semester 2, Day 11 Other Mechanisms of Evolution.
Semester 2, Day 11
Other Mechanisms of Evolution
Agenda Review for Natural Selection Quiz Turn in Homework Take Quiz on Natural Selection Lecture on Other Mechanisms of Evolution Reading/Work Time
Review for Quiz
Genotype, Zygosity, and
Phenotype
Define phenotype and
genotype
Which does natural selection
work upon and why?
Define the four conditions for
natural selection
Define artificial selection
Define natural selection
Understand examples of
each of the following
TYPES of natural
selection:
Directional selection
Disruptive selection
Sexual selection
Stabilizing selection
What is “fitness”?
Homework Due Cornell Notes:
Pages 392-397 (stop BEFORE “Adaptations: Evidence for Evolution”)
Pages 404-409 (stop BEFORE “The Evolution of Species”)
Questions: 15.1 #1, 5 15.2 #1 Chapter 15 Assessment #2, 6, 9, 11, 16, 18-20
Quiz Silently complete quiz Keep eyes on your own paper Flip quiz over when complete
Recall: Evolution Change in a group of organisms over many
generations
CANNOT OCCUR IN AN INDIVIDUAL!
5 Mechanisms of Evolution: Natural Selection Mutations Gene Flow Genetic Drift Nonrandom Mating
Evolution
Mutations: change in DNA that results in a change in
the gene expression
Recall Central Dogma:
3 types of mutations:
Beneficial: benefit organism = HIGHER fitness
Ex. faster runner can survive and reproduce more
Neutral: no effect of fitness
Ex. Eye color doesn’t necessarily help you to survive and reproduce
more
Harmful: hurt organism = LOWER fitness
Ex. People with Huntington’s disease may not survive and reproduce.
DNA mRNA Protein (Gene Expression)
Evolution
How are mutations related to natural selection?
Recall: Natural selection has four conditions:
Variation: differences
Heredity: parent to child
Overproduction: too many offspring
Reproductive Advantage: those able to survive & reproduce pass
on their traits MORE.
Mutations are INHERITED, lead to VARIATION, and can
provide ADVANTAGES
Without mutations, there would be no differences in organisms,
which means no evolution could occur
Evolution
Gene Flow
Movement of
organisms to different
populations
Immigration: enter
area
Emigration: leave area
Results:
MORE variation IN
population
LESS differences
BETWEEN populations.
Evolution Genetic Drift
Taking a small population from a larger one LOSE SOME VARIATION.
Founder Effect: Individuals leave to
start a population ina new area
Bottleneck Effect: Catastrophic event reduces
population
Evolution
Genetic Drift: Founder Effect
Genetic Drift: Bottleneck
Variation of INDIVIDUALS: ensures some INDIVIDUALS
in a species will survive a catastrophic event
Recall: Biodiversity of SPECIES: ensures some SPECIES will
survive a catastrophic event
Evolution
Nonrandom Mating: probability of mating with some
individuals higher than with others
Higher chance of mating with those nearby
Higher chance of mating with those who look similar
Nonrandom mating can lead to INBREEDING:
Continued breeding of closely related individuals
Happens in nature: cheetah bottleneck
Happens artificially: breeding dogs for certain traits
Less Variation = Higher Risk for Disease!!!
Reading/Work Time Cornell Notes on 14.3 and 14.4 Questions:
14.3 #1-3 14.4 #1-5 Chapter 14 Assessment #3, 4, 6, 10-14, 16, 20,
22a, 22c