Plants 3 & Beginning of Evolution

What is thigmotropoism?

A way plants respond to touch where touch triggers an action potential that stimulates pulvinus (structures surrounding the stem) to either loose water and open or gain water and swell closed

What is evolution?

A change in allele frequencies in a population across generations

What is a population?

A group of individuals of the same species who freely interbreed

What is an allele?

A version of a gene

How many alleles do diploids have?

2 alleles per locus

What is phenotype?

The trait that manifests, that we can see

What is genotype?

The genetic sequence that codes for the aspects of a trait

What is a homozygous individual?

An individual with 2 identical alleles

What is a heterozygous individual?

An individual with two different alleles

What is natural selection?

One mechanism of evolution where organisms become better adapted- more able to survive and reproduce

What is the Hardy-Weinberg Equilibrium?

An equilibrium where the allele frequencies don’t change from generation to generation, representing frequencies when only Mendez’s laws are in action (strictly hypothetical)

What conditions need to be met in order to use Hardy-Weinberg Equilibrium?

1. No mutations in the gene pool

2. Random mating

3. No natural selection

4. Extremely large population size

5. No gene flow (moving alleles in and out of a population)

How do you calculate allele frequency?

The frequency = the total number of an allele / total number of possibilities

How do you calculate the frequency of a genotype?

Frequency = total number of a genotype / total number of individuals

What is the hardy-Weinberg equation?

p^2+2pq+q^2=1

Where p is the frequency of the dominant allele and q is the frequency of the recessive allele,

P+q=1

What is directional selection?

Selection in which the overall makeup of a population is shifted towards one extreme of the distribution

What is stabilizing selection?

Selection in which extreme variants at both ends of the distribution are removed

What is disruptive selection?

Variants are favored at both ends of the distribution and the middle of the distribution are removed

What three things must be true in order for natural selection to occur?

1. Variation

2. Heritability

3. Differential reproductive success

What is micro evolution?

Evolution that happens below the species level (small-scale within a single population over a short period of time)

What is macro evolution?

Evolution at the species level and above (large-scale change across species boundaries over a long period)

What is speciation?

The process by which one population divides into two groups that are eventually reproductively isolated meaning they cannot breed and produce fertile offspring

What is allopatric speciation?

A physical barrier separates two parts of a population

What is sympatric speciation?

A mutation separates some individuals in a population