Mr. AltorferMr. AltorferScienceScience

Change Over TimeChange Over Time

Pages 166 to 173Pages 166 to 173

ObjectivesObjectives

1. Identify two kinds of evidence 1. Identify two kinds of evidence that show that organisms change that show that organisms change over time.over time.

2. Explain how comparing organisms 2. Explain how comparing organisms can provide evidence that they have can provide evidence that they have ancestors in common.ancestors in common.

Things change over time. Look at Things change over time. Look at the evolution of the IPOD for the evolution of the IPOD for exampleexample

Evolution of the IPOD and Evolution of the IPOD and PeoplePeople

Do Species Change Over Do Species Change Over Time? Time?

EvolutionEvolution-- The process in which The process in which populations (groups) gradually populations (groups) gradually change over time. change over time.

Charles DarwinCharles Darwin is well known for his is well known for his work on this topic. work on this topic.

Differences Among Differences Among OrganismsOrganisms

Adaptation-Adaptation- A characteristic that A characteristic that helps an organism survive and helps an organism survive and reproduce in its environment.reproduce in its environment.

Adaptations may be Adaptations may be physical physical characteristicscharacteristics or or behaviorsbehaviors that that help the organism survive.help the organism survive.

Differences Among Differences Among OrganismsOrganisms

Examples of Physical Adaptations-Examples of Physical Adaptations- AA giraffe’s giraffe’s long neck. How does a long neck. How does a

giraffe's long neck help it to survive? giraffe's long neck help it to survive?

Differences Among Differences Among OrganismsOrganisms

Examples of Physical Adaptations-Examples of Physical Adaptations- An An elephants’elephants’ trunk. How does an trunk. How does an

elephant’s trunk help it to survive?elephant’s trunk help it to survive?

Differences Among Differences Among OrganismsOrganisms

Examples of Physical Adaptations-Examples of Physical Adaptations- A A person’sperson’s hands. How do our hands hands. How do our hands

help us to survive?help us to survive?

Differences Among Differences Among OrganismsOrganisms

Examples of a behavioral adaptation.Examples of a behavioral adaptation. A A bearbear hibernating. How does this hibernating. How does this

behavior help the bear survive?behavior help the bear survive?

Differences Among Differences Among OrganismsOrganisms

Species:Species: A group of organisms that A group of organisms that can mate with one another to can mate with one another to produce fertile offspring.produce fertile offspring.

Population:Population: Groups of individuals Groups of individuals of the same species living in the of the same species living in the same place.same place.

SpeciesSpecies

American Bull Frogs

Green Frogs

These frogs are two different species of frogs!

Evidence of Changes Evidence of Changes Over TimeOver Time

Fossils-Fossils- The remains or imprints of The remains or imprints of once-living organisms found in once-living organisms found in layers of rocks. layers of rocks.

Comparing OrganismsComparing Organisms

Common Ancestry-Common Ancestry- Evidence Evidence suggests that all living things have a suggests that all living things have a common ancestor or relative. common ancestor or relative.

Example: People are very closely Example: People are very closely related to cats, dolphins and bats.related to cats, dolphins and bats.

Comparing Skeletal Comparing Skeletal StructuresStructures

Human Arm

Cat Leg

Dolphin Flipper

Bat Wing

Bone Structure Bone Structure

Embryonic Development Embryonic Development

Comparing DNAComparing DNA

DNA Evidence-DNA Evidence- DNA Evidence that DNA Evidence that organisms are related to each other.organisms are related to each other. The more two organisms DNA matches, The more two organisms DNA matches,

the more closely they are related to the more closely they are related to each other . each other .

Comparing DNAComparing DNA

When human DNA is compared to chimpanzee DNA they are 98% similar! Wow!