unit 7

Evolution

"descent with modification," a process in which species change and give rise to new species over many generations.

Adaptation

The process of changing to better fit an environment.

Natural selection

Nature’s way of selecting an organism because their trait favors the environment and they tend to survive and reproduce.

Variation

The differences between individuals within a population, which can lead to evolution through natural selection.

biodiversity

the variety of life in the world or in a particular habitat or ecosystem.

Genetic drift

refers to the mechanism of evolution in which allele frequencies of a population change over generations due to chance.

sampling error in genetic drift

random fluctuations in allele frequencies, potentially resulting in reduced genetic variation.

bottle neck effect

is a phenomenon in which a significant reduction in population size leads to a loss of genetic diversity. This can occur due to events such as natural disasters or human activities.

founder effect

is a genetic phenomenon that occurs when a small group of individuals establishes a new population, leading to reduced genetic variation and different allele frequencies compared to the original population.

Genetic drift usually effects larger or small populations?

smaller, since they are more easily effected by changed in alleles.

Gene flow

The movement of individuals between populations causing an exchange of alleles between population

allele

a version of a specific gene

genotype

refers to the specific genetic makeup of an individual, encompassing all the alleles (versions of a gene) they carry.

Darwin’s 3 observations of natural selection

1. Traits are inherited

2. Organisms produce more offspring that can survive

3. offspring’s vary in heritable traits

Traits are inherited

Traits are passed down from parent to offspring

organisms can produce more offspring that can survive

Organisms tend to produce more offspring than the environment can support, leading to competition for resources.

organisms vary in heritable traits

Sine individuals will inherit more favorable traits therefore being able to survive and reproduce more than others.

What are the 4 mechanisms for evolution

1. Natural selection

2. Mutations ( variation)

3. Genetic drift

4. Gene flow

Natural selection

The trait that is favored by the environment which increases survivability and reproduction within an area

Artificial breeding

Humans select desirable traits in other species and selectively breed individuals with the desired traits.

Categories of artificial breeding/breeding

1. pure bred

2. Crossbreeding

3. Mixed-breeding

Pure bred

An individual where is pure bred from parents of the same breed or variety, resulting in consistent traits across generations.

Cross bred

An individual that results from two different types of purebreds

Mixed-bred

An individual that results from crossing two different breeds or varieties, often leading to a combination of traits from both parents.

convergent evolution

the process whereby organisms from different evolutionary backgrounds develop similar adaptations to similar environmental challenges overtime. (lactose intolerance)(analogous structure)

Mutation

A change in the DNA sequence of an organism, which can lead to variations in traits and may be beneficial, harmful, or neutral in effect.

genetic variation