Bio Evolution Unit Review

Embryological Evidence

Shows that organisms that have a closer genetic relationship to one another tend to look similar for a longer period of time during fetal development.

Gene Flow

The increase in variation via two interacting populations

Natural Selection

The process by which organisms with variations most suited to their local environment survive and leave more offspring.

Geological Isolation

These populations do not mate because they cannot reach each other due to a natural barrier

Crossing Over

The increase in variation via chromosomal changes during meiosis

Anatomical Evidence

Shows how multiple organisms are related structurally and functionally, implying the evolved to become more similar or different depending on their environments.

Variation

Differences between the members of a population

Behavioral Isolation

When populations are unable to mate because they do not understand each other's actions.

Monogamy

One to One reproduction

Mimicry

imitating a more dangerous organism for protection.

Species

A group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding.

Genetic Drift

Variation in the relative frequency of different genotypes in a small population, owing to the chance disappearance of particular genes as individuals die or do not reproduce

Camouflage

Blending in with your background

Reproduction

Creation of new, viable offspring

Evolution

The change in the characteristics of a species over several generations, relies on the process of natural selection.

Mechanical/Chemical Isolation

When populations do not reproduce because the differences in the makeups of the reproductive system may be too great to produce offspring

Founder Effect

A decrease in variation via small group of organisms wandering off from their population and beginning a new population (with a more limited gene pool)

Fossil

the remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock.

Disruptive Selection

A shift in the allele frequency in a population that favors both extremes

Ecological Isolation

When a population splits and half go to one ecosystem while the other goes to another ecosystem. These new ecosystems present new and different challenges. The two populations adapt to their new environments and change in the process. Eventually they differ so much they can’t even mate anymore

Homologous Structures

Structures on organisms that share a similar makeup, but serve different functions

Adaptation

Any heritable characteristic that increases an organism’s ability to survive and reproduce in its environment

Intrasexual Selection

Sexual competition within the same sex. Usually two males fight, whoever wins gets the female

DNA Evidence

Shows that organisms that are closely related will have much more similar DNA.

Polyandry

One female, multiple male partners

Vestigial Structures

Structures that were once important but are no longer functional. Implies we evolved to no longer use certain parts of us

Stabilizing Selection

 A shift in the allele frequency in a population that favors neither extreme

Speciation

The formation of a new species

Fossil Evidence

Shows how a specific organism's body structure has changed over time, implying it has evolved.

Population Bottleneck

A decrease in variation via some sort of event severely limiting the populations’ survival, decreases the total amount and overall gene pool.

Finch Beaks

Darwin's original example of natural selection.

Fitness

An organism's ability to survive in its environment

Analogous Structures

Structures on different organisms that have very different makeup, but the same function

Temporal Isolation

These populations do not mate because of different timing expectations (mating seasons or time of day).

Mutations

The increase in genetic variation via small, random changes in the genetic code. Can have good or bad consequences

Heritability

The ability of a trait to be passed on genetically

Gene Pool

The collection of genes in a given population

Directional Selection

A shift in the allele frequency in a population that favors an extreme

Polygyny

One male, multiple female partners

Intersexual Selection

Sexual competition between two sexes. Usually a male tries to impress a female until she chooses to mate with him

Trait

A characteristic that can be passed down to offspring

What is Darwin’s Theory of Natural Selection?

There exists variation in populations. Some traits are more useful than others. These adaptations are favored because they increase fitness. Those with the more useful adaptations will survive and reproduce more, those without them will die off.

How do analogous and homologous structures provide evidence for evolution?

Analogous structures showed that some organisms started differently but evolved to be similar in an effort to better suit their environment. Homologous structures show some organisms all shared a common ancestor but over time evolved differently to suit their diverse environments

What is Speciation?

Speciation is the creation of a new species. An example is when the finches migrated to a new island, separating themselves from their population. Over time, they adapted and changed, until eventually they were so different that they could no longer interbreed with the original population. This formed a new species.

Temporal Isolation

When populations are unable to interbreed due to the fact that they reproduce at different times of the year or the day

Mechanical/Chemical Isolation

When populations are unable to reproduce due to incompatibility with their genitals or gametes

Geographic Isolation

When populations are unable to reproduce due to a geographic barrier like a mountain or river

Behavioral Isolation

When populations are unable to reproduce because they cannot communicate with one another

Ecological Isolation

When populations are unable to reproduce because a population splits and changes too much based on their new environment