Evolution. What is it? Changes that occur in a population over time, in response to the environment.
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Transcript of Evolution. What is it? Changes that occur in a population over time, in response to the environment.
![Page 1: Evolution. What is it? Changes that occur in a population over time, in response to the environment.](https://reader036.fdocuments.in/reader036/viewer/2022081512/5697c0271a28abf838cd6093/html5/thumbnails/1.jpg)
Evolution
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What is it?
Changes that occur in a population over time, in response to
the environment.
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Lamarck
• Acquired characteristics can be passed down form generation to generation
• Organisms evolve over time due to the impact of the environmental factors acting on them
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Darwin• Natural Selection: organisms best suited to
survive will pass their traits down
1. Survival of the fittest2. Struggle for existence (competition for resources,
produce more young than can survive)3. Variation and adaptation
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The Giraffe, Darwin and LamarckLamarck Darwin
Use and disuse
Passing on of acquired characteristics
Increasing complexity
No extinction
Variation
Inheritance
Differential Survival
Extinction
Lamarck: long necks of giraffes due to reaching for higher levels…offspring would inherit the trait…Darwin: longer necks were a result of adapting to the environment…short neck giraffes died off
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BREED ORGANISMS FOR PARTICULAR TRAITS
Selective Breeding
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FossilsThe preserved remains of plants and
animals
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Aging a Fossil
• Carbon dating• Measure the amount
of C-14 (an isotope of Carbon) remaining in the fossil
• Calculate according to half life ( the time it takes for half the amount of a substance to degrade)
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Vestigial Organs• Served a prior purpose• Organism has evolved
and no longer serves a purpose
• Example: human tail bone, snakes have tiny pelvic bones with limb bones, blind salamanders having eyes
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Vertebrates• All vertebrates shared a
common ancestor. • How do we know this? • What evidence is there
for this? • They have evolved from
common ancestry, sharing certain inheritable traits.
• The backbone is the most evident.
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Mutation
• Permanent changes to the DNA sequence resulting in structural changes in a gene
• Peppered Moths: occurred over last two hundred years