Species Variation Obj 6 Describe evidence of species

Species Variation Obj. 6 Describe evidence of species variation due to climate, changing landforms, interspecies interaction, and genetic mutation.

Vocabulary terms: • Adaptation, Speciation, Mutation, Extinction, Genetic Resistance, Isolation,

• Over time, animals may change behavior or physical appearance in response to changes in the environment. This is called adaptation.

• Adaptation- a characteristic that improves an individual’s ability to survive and reproduce in a particular environment.

• Adaptations may be physical, such as a long neck or striped fur. Adaptations may be behaviors that help an organism find food, protect itself, or reproduce.

• Scientists think that Earth has changed over time. Scientists estimate that Earth is 4. 6 billion years old.

• Scientists think that as populations have changed over time, new species form. Newer species descend from older species.

• It was proposed that evolution, happens to population gradually over long periods of time. The scientist gathered this information through fossil records and common ancestry. Darwin proposed his theory of evolution in 1859 based on his observation in the Galapagos island.

• Evolution- process in which populations gradually change over time.

• Evidence that organisms evolve can be found by comparing living organisms to each other and to the fossil record. • The process of evolution is indicated by fossil records and common ancestry.

• It was proposed that evolution happens through a process called natural selection.

• Natural selection- the process by which individuals that are better adapted to their environment, survive and reproduce more successfully than less well adapted individuals do of the same species;

• The four parts of natural selection are: • 1. Overpopulation ( some eggs survival –other do not) • 2. Inherited Variation (Every individual has its own combination of traits)

• 3. Struggle to Survive (some die because of predators, starvation, and disease) • 4. Successful Reproduction (those best adapted to the environment have many offspring that survive)

New Species • A new species can form when a group of individuals remains isolated from the rest of its species long enough to evolve different traits. This isolation can be due to climate, changing landforms, interspecies interaction, or genetic mutations and bring about speciation.

• The Grand Canyon squirrel populations represent an example of species variation due to changing landforms. As the Colorado River cut through the landscape, it caused the squirrel population to become separated into two groups. The two groups, although similar in appearance, cannot reproduce with each other because they have developed into two separate species.

• • Pictured to the left Kaibab squirrel Pictured to the right Albert Squirrel

• Speciation- formation of new species as a result of evolution.

• The three steps of speciation are: 1. Separation (part of a population becomes separated from the rest) 2. Adaptation (the separated group may evolve different sets of traits ) 3. Division (two separated groups may become very different; groups may not be able to interbreed anymore)

Extinction • This is natures way of getting rid of weaker species. Only the fittest of the species will survive.

• Extinction-describes a species that has died out completely.

DNA resistance • Organisms with shorter life spans can adapt changing conditions more rapidly through mutations. These mutations lead to genetic resistance to substances such as insecticides and antibiotics.

• Genetic Resistance- It occurs when alterations to the DNA makes the species stronger and allows them to survive in any environment that they may encounter.

• • • Isolated populations can be unable to interact with each other because of geographic boundaries like an ocean or mountain. They can develop unique characteristics and cannot breed. Two populations can be isolated if they feed at different times or reproduce at different times of the year. Two or more populations may evolve differently from each other.

• Isolation stops populations from interbreeding so new species evolve.

• Isolation- refers to species being separated.

Survival of the fittest • Organisms that have adapted to their changing surroundings pass on the traits that protect their offspring.

Interaction between organisms • There are four ways that species and individuals affect each other: competition, symbiotic, predator and prey. • Let’s look at each one.

Competition • When two or more individuals or populations try to use the same resource, such as food, water shelter, space or sunlight.

Prey • An organism that is killed and eaten by another organism.

Predator • An organism that eats all or part of another organism.

Symbiosis • A relationship in which two different organisms live in close association with each other.

Mutualism • A relationship between two species in which both species benefit.

Commensalisms • A relationship between two organisms in which one organisms benefits and the other is unaffected.

Parasitism • A relationship between two species in which one species benefits and the other is harmed.

Parasite An organisms that feeds off another organism and the host is harmed

Host • The organism in which the parasite lives and receives its food from.