Chapter 23 Flashcards
What is polygenetic inheritance?
A characteristic that is controlled by more than one gene.
What is a genotype?
Is defined as the composition of genes which also includes both expressed and unexpressed
What is a phenotype?
It is the physical outcome of genes, the expressed allele.
how does natural selection work on a population?
A population can have natural selection work on their GENOTYPES. As individuals they only work on phenotypes.
Can natural selection work on individual genotypes?
Only on the alleles that are expressed and only on a population.
What is an example of a polygenic inheritance?
The two caterpillars that look very different but turn into the same type of moth. They are different in appearances to chemicals in their diets, not differences in their genotypes.
How is microevolutionary change measure?
It can be measured in the difference of allele frequencies over time. (Rabbit diagram with white and brown bunnies)
What is the Hardy-Weinberg equilibrium equation? what does each part represent?
P^2 + 2pq + q^2 = 1;
P^2 = the frequency of the dominant allele in a population. (Homozygous Dominant)
q^2 = the frequency of the recessive allele in a population. (Homozygous Recessive)
2pq = Heterozygous
Does the Hardy-Weinberg equation have to equal 1?
Yes the frequencies of the three genotypes must equal 1 (100%) in any population.
What are the conditions or assumptions of Hardy-Weinberg Equilibrium?
- No mutations
- Random mating
- No natural selection
- Extremely large population size
- No gene flow
What was talked about about the Underwing Moths?
They camouflage in with the tree but if they are ever scared they will open up their wings where bright colors will show. It will scare predators away.
Why are peppered moths so famous?
Their experiments were said to “prove” evolution wrong because they saw that one moth lands on the tops of trees, while the black moths would land on the trunks of tree that turned black from soot.
What are the two types of genetic drift?
Founder effect and the bottle neck
What is the founder effect?
The founder effect is when a few individuals from a population start a new population with a different allele frequency than the original population. (When a storm blows some bugs from one island to another and they start to breed.)
What is the bottle neck effect?
It could happen because of diseases and disasters etc. A bottle can be full of diverse alleles but through bottle necking only a few survive. (examples of bottle neck is the cheetah and the prairie chicken) Bottle Neck causes allele pools to become a lot smaller and most wont be able to survive.
What is genetic drift?
Chance events that can also cause allele frequencies to fluctuate unpredictably from one generation to the next.
What is gene flow?
Gene flow is the exchange of genes between two populations.
Why is gene flow not good on a population/generation?
Because the longer a certain organism has lived in an area the better adapted they are. If they reproduce new species will come in and they wont be as adapted to an environment which lowers heath.
What are the different kinds of selection?
Directional selection
Disrupting selection
Stabilizing selection
What is Directional selection?
When pressure is put on an original population and the alleles shift (white mice stands out so they dont survive)
What is Disrupting selection?
When pressure is put on a population and the two extremes will survive. (white mice and black mice survive)
What is stabilizing selection?
where the middle grows stronger. (Brown mice survive) (makes a higher “U” shape than the original shape)
Remember info on Sickle cell.
Infected mosquitoes can spread malaria. A mosquito (the vector) bites someone with the disease they will spread. Sickle cell is a condition where the blood does not hold the needed nutrients to survive and function correctly. It makes a shape like a sickle and has sharper edges. This causes more clogging in the arteries and veins.
