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Change over Time

Change over Time. Pages 104 - 111. All of these frogs live in the same area. What differences are there?. Differences among organisms. Each organism has a different adaptation to help it survive. Adaptation – a characteristic that helps an organism survive and reproduce in its environment

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Change over Time

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  1. Change over Time Pages 104 - 111

  2. All of these frogs live in the same area. What differences are there?

  3. Differences among organisms • Each organism has a different adaptation to help it survive. • Adaptation – a characteristic that helps an organism survive and reproduce in its environment • Examples: structures to find food, protection, or moving from place to place.

  4. Species • A group of organisms that can mate with one another to produce fertile offspring. • Ex: giraffe, lion, rhino

  5. Species over time • The Earth is a very old planet that scientists estimate to be 4.6 Billion years old. • Life has existed on this planet almost as long. • Living things have changed with time. • Some died, some survived, and some changed. • What caused the change?

  6. Evolution • The process by which populations accumulate inherited changes over time. • Because of evolution, scientists believe all living things come from a common ancestor.

  7. Evolution Evidence • The largest piece of evidence for evolution is the fossil record. • Fossils – the solidified remains or imprints of once-living organisms • Fossils are made when an organism dies or leaves an imprint that gets covered by sediment layers.

  8. Fossil Record • The fossil record supplies evidence about the order in which evolutionary changes have occurred. • Older fossils are found in deeper layers, while newer fossils are found in layers near the surface.

  9. Gaps in the Fossil Record • We do not have a complete fossil record of all organisms. • Fossils are rare and not easily preserved. • Conditions for making fossils are not always present.

  10. Human skull shape

  11. Vestigial structures • The remnants of once useful structures. • Ex: Whales • Whales are mammals that need air to breath • Why are they living in the water? • There are remnants of what used to be hip bones and leg bones in whales today • Whales might have ancestors that walked on land

  12. Whale Evolution

  13. More Evidence • If we look at similar structures on different organisms, we see how similar the structures are. • Humans, cats, dolphins and bats come from a common ancestor

  14. DNA Comparison • With the development of genetic engineering, we are able to look at DNA from several species and compare how similar they are. • All organisms share some genetic material. • Scientists look at matching sequences of base pairs • Ex: Chimpanzees and gorillas are close relatives, while chimpanzees and turtles are distant relatives.

  15. Comparing Embryonic Structures • Early in development of any species, an individual goes through embryonic stages. • In the early stages, organisms with a common ancestor look very similar. • As organisms grow, they develop the features that make them different.

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