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Evidence of Evolution Main Types of Evidence 1. Fossils 2. Homologous structures 3. Embryology.

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Presentation on theme: "Evidence of Evolution Main Types of Evidence 1. Fossils 2. Homologous structures 3. Embryology."— Presentation transcript:


2 Evidence of Evolution

3 Main Types of Evidence 1. Fossils 2. Homologous structures 3. Embryology

4 Fossil record Fossil record Layers of rock contain fossils o new layers cover older ones creates a record over time o fossils show a series of organisms have lived on Earth over a long period of time

5 Fossils tell a story… the Earth is old Life is old Life on Earth has changed

6 Fossil Record Fossils are evolutionary evidence Fossils show that ancient species share similarities with species that now live on Earth. Fossils records provide evidence that living things have changed over time. GlyptodontArmadillo

7 Comparing Anatomy Homologous structures Analogous structures Vestigial structures

8 Compare the bones The same bones under the skin o limbs that perform different functions are built from the same bones How could these very different animals have the same bones?

9 Homologous structures Structures that come from the same origin homo- = same -logous = information Anatomically similar structures inherited from a common ancestor These structures can be similar in arrangement and/or function.

10 Homologous structures Forelimbs of human, cats, whales, & bats o same structure on the inside o same development in embryo o different functions on the outside o evidence of common ancestor

11 Analogous Structures Structures that do not have a common evolutionary origin but are similar in structure. Shows that functionally similar features can evolve independently of each other Ex: wing of an insect and wing of bird

12 Analogous Structures

13 Vestigial Structures A body structure that has no function in a present- day organism but was probably useful to an ancestor. This shows a change over time

14 Hind leg bones on whale fossils Why would whales have pelvis & leg bones if they were always sea creatures? Because they used to walk on land!

15 Evolution Chapter 15

16 Comparing Embryos Embryo: the earliest stage of growth and development of both plants and animals Vertebrate embryos exhibit homologous structures during certain phases of development but become totally different structures in the adult forms.

17 Comparing Embryos Similar embryo development may suggest a common ancestor

18 Biochemical Evidence Common ancestry can be seen in the complex metabolic molecules that many different organisms share. Comparison of the DNA or RNA of different species produce biochemical evidence for evolution

19 Biochemical Evidence Comparisons of the similarities in amino acids and other molecules across species reflect evolutionary patterns seen in comparative anatomy and in the fossil record.

20 Knowledge Check True or False Organisms with similar anatomy share similar DNA sequences.

21 Knowledge Check Which of the following best explains how the fossil record provides evidence that evolution has occurred? AIt indicates the exact cause of structural and behavioral adaptations of organisms. BIt shows that the form and structure of groups of organisms have changed over time. CIt shows how the embryos of many different vertebrate species are very similar. DIt indicates that forms of life existed on Earth at least 3.5 billion years ago.

22 Knowledge Check The occurrence of the same blood protein in a group of species provides evidence that these species a. evolved in the same habitat. b. evolved in different habitats. c. descended from a common ancestor. d. descended from different ancestors.


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