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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

Change over Time

Pages 104 - 111

differences among organisms
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.
  • A group of organisms that can mate with one another to produce fertile offspring.
  • Ex: giraffe, lion, rhino
species over time
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?
  • The process by which populations accumulate inherited changes over time.
  • Because of evolution, scientists believe all living things come from a common ancestor.
evolution evidence
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.
fossil record
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.

gaps in the fossil record
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.
vestigial structures
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
more evidence
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
dna comparison
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.
comparing embryonic structures
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.