evidence for evolution powerpoint

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Evolution: Evidence SC.912.L.15.1 Explain how the scientific theory of evolution is supported by the fossil record, comparative anatomy, comparative embryology, biogeography, molecular biology, and observed evolutionary change

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Page 1: Evidence for evolution powerpoint

Evolution: Evidence

SC.912.L.15.1 Explain how the scientific theory of evolution is supported by the

fossil record, comparative anatomy, comparative embryology, biogeography,

molecular biology, and observed evolutionary change

Page 2: Evidence for evolution powerpoint

Types of Evidence we will be covering

• Fossil Records– Transitional fossils

• Comparative Anatomy– Homologous Structures– Analogous Structures

• Vestigial Structures • Biogeography

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Fossil Records • Fossils support the idea

of evolutionary progression.

• By looking at fossils Paleontologists/zoologists can: – Identify extinct animal

species – Follow the path of

evolution through different stages of development

Evolution of the Whale

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Key Points of the Fossil Record

• Provides evidence of evolution from one species to another– Shows ancestral

intermediates

• Only hard tissue is preserves

• Fossil Formation

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Transitional Fossils

• FLASH CARD ALERT: • TRANSITIONAL FOSSIL: fossils

that show transitions in evolution.

• Transitional fossils are RARE findings – Small proportion of

organisms become fossils

– Many fossils represent dead evolutionary branches

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Support: Comparative Anatomy • Homologous Structures:

Similar features found in different species that are derived (come from) a common ancestor – Ex. Tetrapod limbs, fur,

lungs • Bone formation:

developmental and evolutionary similarities

• Evidence of intermediates

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Analogous Structures

• FLASH CARD ALERT: • Analogous Structures: a trait or an organ that

appears similar in two unrelated organisms• Happens because of convergent evolution: – FLASHCARD ALERT: CONVERGENT EVOLUTION: Species

evolve in similar environments and have similar environmental stressors/survival factors

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Analogous Structures

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Vestigial Structures

• Vestigial Structures: characteristics found in existing species that have no known function

• Provide evidence of common ancestry• As species evolve their structures change– Two things will happen • Species will adapt the organ/structure to a new use

– penguin

• The organ or structure will no longer have a use – Whale pelvis/snake feet.

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Useless for Flying but excellent for swimming

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Vestigial Structures

• Stubs on pythons, boas, and other snakes– Ancestral legs

• No known function

• Useless Vestigialstructures are BETTER sourcesof evidence forevolution

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Amphiuma

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Flightless Wings

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Plica semilunaris

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CFU:

• What is the major difference between analogous and homologous structures?

• What structure is the best evidence of evolution: analogous, homologous or vestigial

• What kind of tissue/part of an animal is preserved in fossils?

• What type of fossils are paleontologists most interested in?– Why are they hard to find?

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Comparative Embryology

• Incredible similarities in embryos of different species provides evidence of common ancestor – Patterns of embryo

development are also important.

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Biogeography

• Zoologists seek to understand how very closely related species ended up in completely different parts of the world

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Support for Pangaea

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Key Point of Biogeography

• Seeks to answer the question: how/why different but similar species exist in similar yet separate parts of the world

• Can be explained by geological changes, migrations, convergent evolution

• Support ideas of common ancestor and Pangaea

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EVOLUTION CFU

• What are the five steps of evolution?• How does the environment affect the process of

evolution?• Adaptations help the organism: • The three types of structures that support evolution

are: • Paleontologists are excited to find what kind of

fossil and why?