UNIT 2 DAY 7 - POPULATION GENETICS

Question 1

ephemeral

Answer 1

lasting for a very short time

Question 2

Darwin thought heredity was

Answer 2

• blending –> the fusion of parental traits which leads to intermediate versions of those traits in offspring

Question 3

Why is blending not legitimate way to think of genetics

Answer 3

1. traits are built of hereditary particles named genes –> transmitted unchanged through generations unless altered by mutations (CAN’T BLEND)
2. individuals carry 2 copies of each gene (one gene from each parent)

Question 4

Gene

Answer 4

stretches of DNA that codes for a protein

Question 5

chromosomes

Answer 5

genes grouped together in the nucleus of the cell

Question 6

diploid

Answer 6

2 alleles of each gene –> an individual inherits one set of chromosomes from her father and one from her mother –> 2 copies of each gene

Question 7

allele

Answer 7

an alternative form of a gene

Question 8

phenotype

Answer 8

traits built by 2 alleles (physical characteristics)

Question 9

genotype

Answer 9

2 alleles that build a trait (genetic composition)

Question 10

homozygous

Answer 10

both alleles are the same

Question 11

heterozygous

Answer 11

alleles are different

Question 12

gene pool

Answer 12

all the genes, including the different alleles for each gene, that are present in a population at any one time

Question 13

macro-mutation

Answer 13

mutation of large phenotypic effect (lamarck’s theory of acquired traits based off of this)
- single step process

Question 14

Hardy-Weinberg equilibrium

Answer 14

• as long as members of a population mate randomly, both allele and genotype frequencies will remain constant
• allele frequencies do not change over time
• no change of random genetic drift, natural selection or gene flow
• created NON-EVOLVING POPULATION

Question 15

Hardy-Weinberg equation

Answer 15

• reproduction and random shuffling of alleles that accompanies it –> doesn’t cause evolution alone

Question 16

evolution (genes)

Answer 16

change in allele frequencies in a population over time

Question 17

What forces can cause evolution

Answer 17

1. Natural selection - ALWAYS increases adaptation of species
2. mutations - provide new alleles by altering existing ones (could increase/decrease adaptations)
3. genetic drift - allele can increase or decrease in frequencies by chance events (more effective in small populations -bottleneck/founder events) (could increase/decrease adaptations)(can cause maladaptation - failure to adjust to an environment)
4. gene flow - introduction of new alleles to the population or increase the frequency of alleles already found in the population
   - could increase/decrease adaptations effects: (little effect to overall population)(major allele frequency change)(prevents species from evolving into 2 different species)(large population sending genetics to small population can restore genetic variation)

Question 18

maladaptation

Answer 18

failure to adjust to an environment –> beneficial genes removed to form gene pool

Question 19

bottleneck effect

Answer 19

large population becomes a small population due to environmental disaster, new predator or new competitor

Question 20

founder effect

Answer 20

• few members of a large population migrate to new location and establish a new population
• form genetic drift

Question 21

stream-side salamander and green sunfish case: gene flow

Answer 21

• predator: gene sunfish (Lepomis Cyanellus)
• prey: Streamside Salamander (Ambystoma barabouri) –> larvae is the prey
• 2 habitat types:
• emphemeral stream (fast drying stream)
• larvaw try their best to increase activity levels that reduce larval period lengths
• sunfish predator: larvae suffers high rates of predation, larvae tries to be less active during the days and hides
• negative effects of gene flow: gene flow from fish-less populations to a fish population that creates a maladaptation (taps, feeding and survival time w predator)