What was one of Lamarck’s principles?
-
Use and disuse
Acquired traits
Who was Lamarck?
-
First scientist to identify descent between fossil taxa and living taxa
Name Darwin’s two ideas
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Descent with modification
Natural selection
Define natural selection
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Mechanism by which descent with modification occurs
Reproduction of the fittest
True or false: natural selection acts on a population
-
False
Why does natural selection continue (why is there never a perfect organism?)
-
There is never a static environment
True or false: when pathogens are treated with a drug, it is only the individuals of the pathogen that
develop the ability to fight back that reproduce and pass their newly acquired trait on
-
False
Why is the above false?
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Because inherited traits are not passed on; the individuals who survive will be the individuals
who already have something in their genome that is resistant to the drug. Those will be the
individuals unaffected, and so will be able to potentially pass on their genes to the next
generation.
Give an example in the animal kingdom of a homologous trait
Define what a homologous trait is
-
Similarity in structure resulting in common ancestry
Give an example of a vestigial trait in the animal kingdom
Define vestigial
-
Useless, leftover, unused inherited trait (doesn’t hurt or help)
Define a population
-
A localized grouping of the same species
What are the three mechanisms of microevolution?
- Genetic drift
- Natural selection
- Gene flow
What are the two mechanisms of genetic drift?
-
Founder effect
Bottleneck effect
Example of the Founder effect?
Example of Bottlenecking?
What is the source of NEW alleles?
-
Mutation in the inherited DNA
Impossible to predict
What can the genetic composition of a population be described as?
-
Gene pool
Define gene pool
-
Alleles for all loci in all individuals of a population at a given time
Describe a fixed allele
-
Only one allele at a locus across all individuals of a population
Define allelic frequency
-
The proportion of a given allele in a population
What does the Hardy Weinberg theorem tell us about a population?
-
Allelic frequencies of a population
Name the five things that have to be true to use the Hardy-Weinberg equilibrium
-
Large N
No migration
No mutation
No natural selection
Random mating
What will result if there is a departure from the conditions of the HW equilibrium?
-
Evolution
What is the equation for the HW equilibrium?
p2 + 2pq + q2 = 1
What is the auxiliary equation for the HW equilibrium?
p+q=1
What does the p represent in the HW equilibrium?
-
Frequency of dominant ALLELE (dominant allelic frequency)
What does the q represent in the HW equilibrium?
-
Frequency of recessive ALLELE (recessive allelic frequency)
What does the pq represent in the HW equilibrium?
-
The heterozygous frequency of a population
What example was given in class of a disease whose frequency can be measured with the HW
equilibrium?
-
PKU or phenylketoneuria disorder
Homozygous ___________? (recessive)
How do we define microevolution?
-
Change in allelic frequencies over time
Genetic drift, gene flow, natural selection
T/F: Microevolution is most significant in large populations
-
False
What was the example of the Bottleneck effect given in class?
-
Northern elephant seals
Allele fixation
How could we alleviate the problems of allelic fixation in the northern elephant seal population?
-
Introduce southern seals
Gene flow
What was the example of the founder effect given in class?
-
Tristan de Cunha, British settlement
Pigmentosa carrier
Damage to retina
What is the only cause of microevolution that is likely to adapt the population to its environment?
-
Natural selection
What are the three modes of natural selection?
-
Directional
Disruptive
Stabilizing
Draw a picture of each graph
What is sexual selection?
-
Natural selection for mating success
What can sexual selection result in?
-
Sexual dimorphism
What is the difference between intrasexual selection and intrasexual selection?
-
Intra: competition among [usually males] for mates of opposite sex
Inter: selection o f one sex to choose an partner of different sex
What prevents natural selection from reducing variation?
-
Diploidy
Heterozygote advantage
Natural variation
Give an example of a pre-zygotic barrier
-
Habitat isolation
Temporal isolation
Behavioral isolation
Gamete isolation
Mechanical isolation
Give an example of post-zygotic barrier
-
Reduced hybrid viability ( gene mix sucks)
Reduced hybrid fertility (sterile F1)
Hybrid breakdown (F2 sucks)
Define pre-zygotic barrier
-
Act prior to formation of zygote
Blocks mating/fertilization
Define post-zygotic barrier
-
Act after the formation of zygote
-
Prevent hybrid zygote from developing/maturing
What is the biological species concept?
-
Individuals between one or more populations that have the potential to interbreed in nature
and produce viable offspring
Limitations of BSC?
-
Hybridization not always sterile
Majority of species asexual
Cannot test in fossil species
Geographically isolated populations never have an opportunity to mate in nature
Give an example of other ways to define species
-
Morphological species concept
Ecological species concept
o Niche
Phylogenetic species concept
o Smallest group of individuals sharing common ancestor
Define allopatric speciation
Define sympatric speciation
What is a hybrid zone?
What is reinforcement of a hybrid zone?
-
Natural selection strengthens prezygotic barriers to reproduction reducing formation of hybrids
What is the fusion of hybrid zone?
-
When two species contact one another and reproductive barriers are not strong
Speciation reversed
Give an example of misconceptions of evolution and EXPLAIN
-
No transitional fossils
Evolution occurs in individuals
Evolution only happened in past
Considerable doubt about validity
Species are perfectly adapted
Evolution always leads to more prefect species
It is an explanation for origin of life