EVOLUTIONARY ARMS RACE

REVIEW

What is a trait?

A trait is a notable feature in an organism. (examples: personality, size and shape of noses, color and shape of feathers , etc.) Traits are passed on prom parents to offspring.What is an adaptation?

An adaptation is a trait that helps an organism survive and reproduce in its environment. (examples: Beak shape, tail length, opposable thumbs, camouflage, etc.)

What is the theory of evolution? Evolution is the gradual change in a

species to become better adapted to a specific environment.

How does evolution happen? In nature, evolution happens through

the process of natural selection.

What is natural selection? In natural selection, individuals that

are better adapted to their environment are more likely to survive and reproduce than other members of the same species.

Natural selection and…

Overproduction: A species produces many more offspring that could conceivably survive. How does this ensure the survival of a species?

Variations: Differences between individuals of a same species. How does this ensure the survival of a species?

Natural selection and…

Competition: Individuals must compete for limited resources. Who gets to pass on their traits?

Selection: Some variations are better suited for a particular environment. The organisms that have these variations are more likely to survive. In a desert, who survives, the organism that can go longer with or without water?

Natural selection states that helpful variations gradually accumulate in a species, while unfavorable ones tend to disappear.

What unfavorable characteristics do you think made the wooly mammoth disappear when the environment changed?

Does a species decide to evolve when in a new environment? No. Genetic variations in individuals

happen “by chance”. However, if the variation is favorable, that individual will most likely survive and be able to pass on it’s traits.

What happens if the variation is unfavorable?

Evidence for evolution

What tells you that you are related to your biological parents?

The same occurs with evolution.

Similarities in body structure.

Compare these structures. How are they similar? How are they different? What does this tell us?

Similarities in early development

Compare these embryos; can you tell the species?

Similarities in DNA and Proteins

According t the chart, who are we more closely related to?

How do new species form?

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 may be result of geographic isolation or reproductive isolation.

In geographic isolation, one group of individuals is physically separated from another due to a change in the landscape.

In reproductive isolation, one group is unable to breed with another because of predation or other factors.

How do species become extinct? Extinction is caused by a change in a

species environment. The members of the species may not have adaptations that allow them to survive and reproduce in a changed environment.

Examples: Predation, Climate change.

Naming Species

Species are named using the Linnaeus system.

The Linnaeus system provides two names to identify a particular species. Much like you have a First and Last name.

What do these three organisms have in common?

Felis concolor Felis domesticus Felis leopardus

Well they all belong to the Felis family

What about these?

Which do you think are more closely related?

The more classification levels that two organisms share, the more characteristics they have in common.

Canis indicusCanis lupus

Canis lupus familiaris

Let’s try with plants. Which two would share the most characteristics? Which would be the most different?

Malus sylvestris Malus domestica Prunus persica Pinus palustris

Rosacea PinaceaeFamily:

Standards practice

Turn to page 261 in your textbook. Answer the test and turn it in for credit.