5-2 Notes Adaptation & Extinction

Chapter 5, Lesson 2

Adaptations

• Humans can change their environment to meet their needs.

• Organisms have evolved adaptations to their environment by the process of natural selection.

Adaptations

• Adaptations are inherited traits that increase an organism’s chance of surviving and reproducing in a particular environment.

Tarsier

Adaptations

• Not all traits are adaptations.

• Sometimes undesirable traits can be passed down because they are genetically linked with other beneficial traits.

Adaptations

Adaptations

• Adaptations are the final products of the long process of natural selection.

• Adaptations are naturally selected for, not intentional.

Structural Adaptations

• Structural adaptations are aspects of the physical body that help organisms survive and reproduce.

Structural Adaptations

• Camouflage is coloring that blends with the environment, and makes organisms difficult to see.

Camouflage…

Camouflage…

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Camouflage…

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Structural Adaptations

Camouflage…

Structural Adaptations

• Mimicry is when one species (the mimic) looks like another species (the model) in order to deceive a third species.

Structural Adaptations

• Batesian mimicry is when the model organism is dangerous or venomous, but the mimic is not dangerous.

King Snake (mimic) – harmlessCoral Snake (model) - venomous

“Red on yellow,will kill a fellow.”

Structural Adaptations

• Mullerian mimicry is when both the model organism and the mimic are dangerous or distasteful.

Monarch and Viceroy Butterflies – both taste bad

Structural Adaptations

• Self mimicry is when a species fools its prey by looking inviting or familiar OR to scare off a predator.

The owl butterfly’s eyespot canconfuse a predator OR gives thepredator a false target.

Behavioral Adaptations

• Behavioral adaptations are actions or behaviors that help organisms survive and reproduce.

Male bower bird decorates his nest to attracta mate.Bird of Paradise dances for a mate.

Behavioral Adaptations

• The herding instinct is seen in cows, and they know a large group is less likely to be attacked than when alone.

Often, adaptations are BOTH structural and behavioral. Check out the Bird of Paradise. 2:40

http://www.youtube.com/watch?v=SB8UodV_DJg

Extinction

• A species becomes extinct when all the individuals of a particular species die off.

• There have been several major extinction events in history.

Extinction Cause: 1. Loss of Habitat

• As humans develop and occupy more space, and use more resources, habitats are destroyed.

Extinction Cause: 2. Loss of Genetic Diversity

Cheetahs were greatly endangered about 10,000 years ago.

The few that remained had to inbreed, which is why they are so identical

today.

• Species NEED genetic variety to make it more likely to survive.

• A species is considered to be threatened if they are likely to become endangered due to low genetic variation.

• Cheetahs are threatened because they had to inbreed and now have low genetic variation.

Extinction Cause: 3. Competition with Exotic Species

The kudzu plant was introduced into the Southern USA from Japan in the 1930sto help prevent soil erosion. It has taken

over some areas because it grows so quickly (30 cm / day).

• Humans often introduce a new species to an area because it is unique or pretty.

• If it has no known consumer, it will take over and kill native species.

Extinction Cause: 4. Inability to Adapt

• This is involved in rapid environmental changes, and can cause rapid extinction.

• If the climate changes suddenly, and a species doesn’t have any individuals with genetic traits that allow them to adapt, the entire species will go extinct.

What is not an example of an adaptation?

A inbreeding

B camouflage

C mimicry

D behavior

5.2 Adaptation and Extinction

Why do some non-desirable traits remain in a population?

A selective breeding

B mutation

C they are genetically linked to more beneficial traits

D they may be useful in the future

5.2 Adaptation and Extinction

What cause for extinction would most likely be involved in rapid environmental changes such as climate change?

A loss of habitat

B inability to adapt

C loss of genetic diversity

D competition with exotic species

5.2 Adaptation and Extinction

Which of the causes of extinction is not influenced by human actions?

A inability to adapt

B loss of genetic diversity

C loss of habitat

D competition with exotic species

Why do desert rabbits have mottled fur?

A behavioral adaptations

B mimicry

C camouflage

D incomplete dominance

When do we designate a species as threatened or endangered?

A when there is one population left

B when the number of individuals falls below a certain level

C when population numbers are declining

D when genetic variation is low

SCI 3.e