Exam 2 Flashcards
What is fitness?
non-random differences in reproductive capacity
What is an example of adaption as a feature?
A babies head is large but flexible. However this predates live births and all vertebrates have flexible heads even without live birth.
What is preadaption?
vertebrates head example of heads being flexible before live birth.
What is exapptation?
When a species can no longer do what was originally could but has now changed. An example of this is swimming birds that can no longer fly
What things can change features that are not adaptations?
Physical/chemical rules
Drift
Correlation with adaptive trait
What are the levels of natural selection
Alleles -> usually by its effect on individuals
Individuals -> one or both sexes
Population -> groups
Species
What are the most common types of natural selection?
Most common -> Alleles, Individuals
Not common -> Population, Species
True or False -
Processes of NS at different levels may oppose each other
True
What are ways you can tell if something is an adaptation or not and give examples or definitions
Design Principles - follows certain things that benefit the species hence the adaptation from NS. Fish are torpedo shaped which is an adaptation for speed
Comparative Method- Compare multiple species. Monogamous gorillas have smaller balls then polyamerous chimps
Experiments- Conducting an experiment to test a hypothesis. Soard tailed fish, males with had it removed and placed on a different male without one. Then they watched mating patterns.
Natural selection among genes
T locus polymorphism in house mice are starel if they have the homozygouse recessive allele. However the heterozygoes individuals can still reproduce and they have an uneven spread of the recessive and dominant alleles
Natural Selection among Individuals
Spots on guppys are attractive however they attract preditation as well. This means that they are more likely to reproduce but also to be eaten.
Among Groups
Altruistic traits will increase the fitness of others in the groups around the one with the trait. Will always decrease in frequency because of individual selection. The benefit to the group usually outweighed by cost to individual because individuals reproduce faster then groups. Examples are alarm calling, food sharing and grooming
What is kinship?
Offspring resemble their parents
What is altruisim and what can it do?
It is when there is a trait in an individual that benefits the group. These are favored within the groups because they see the benefit and treat the individual nicely
What are three thing they you should not expect of NS?
Necessity - Polar bears having a white coat to blend in to survive
Perfect - The nerve that goes around your artery
Progress - NS is local, no mechanism to explain species anticipating future
(change is varied and unpredictable)
Morality - everything to be fair. The stronger individual is likely to survive over the weaker one in the wild.
True or false -
Without mutation the only variation would be caused by environmental variation
True
How does variation arise?
From mutation and recombination
True or false -
Dominance of an allele does refer to the frequency of the allele
False -
Dominance of an allele does refer to the frequency of the allele
What is a gene?
The place on a chromosome
What is an allele?
Actual sequence of DNA
What is a point mutation?
Single base change - mistake in replication that changes base pairs in the DNA strand
Often do not affect the protein -
If they do affect the protein it might not affect the phenotype -
Non-coding regions of the DNA can potentially affect the phenotype
What is nonsynoymous?
it does change the amino acid and the protein
What is synonymous?
it does not change the amino acid
What are examples of small scale mutations?
insertion of a base shift reading frame
deletion
What are the different types of structural mutations?
deletion duplication inversion fission fusion
What is anagenisis?
Change in heritable variation over time using the frequency of genotype and alleles in the population
What does polymorphic mean?
That there is more then one allele in the population. Or more then one gene
What does monomorphic mean?
That there is only one of those alleles in the population and the only way to evolve is to mutate
How can polymorphic species change?
Change comes with frequency of genotype and potentially allele frequency
What are the meaning of the letters in the HW equation?
p2+2pq+g2=1
P2 - frequency of A1 homo
2pq - frequency of hetero
q2 - frequency of A2
How do you find the genotype frequency?
Divide the number of each genotype by the total number in the population
What is polyploidy?
Entire sets of chromosome can be duplicated
What is fusion?
genes on two different chromosomes getting combined into one chromosome
What is fission?
Single chromosome is split into two.
How do most mutations occur?
During replications error during cell division
What is pleiotropic?
Most mutations that affect phenotype affect more than just on characteristic
True or false -
mutation that effects phynotype may or may not have an effect on fitness
True -
fitness depends on environment
How do most mutations effect phenotype and fitness?
Most are negative mutations
What four things are true about the randomisation of mutations?
Does not mean they are equally likely, not all regions of DNA are equally mutable
Does not mean that the environment can not cause them
Does not mean we can not predict when any particularly mutation will happen
It is random with respect to the environment, fitness of a mutant depends n the environment but the environment does not always cause “good” mutations
What did luria and delbruck find out
spontaneous mutation that happened in lineage before antibiotics was how they were able to pressist
What are ways to tell genetic from environmental variation?
Crosses -
Correlation between parents and offspring
Twin studies - growing up in different environments but with same genetics
Common garden experiment -
Artificial selection experiments -
What is the difference between absolute fitness and relative fitness?
Absolute - per capita growth rate, W = absolute fitness
Relative - more general describing how selection will change genotype frequency, w = relative fitness
How do you calculate relative fitness?
Each genotype’s absolute fitness is divided by that of the reference genotype
True or false -
equal phenotypes have equal fitness
True
there can be selection of genotype, what is selected for is phenotype
What does directional selection do?
Favors one allele over the other
What is balancing selection?
Tends to maintain genotype and allele frequency at intermediate level
