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Evolution. What is evolution? Change over time Questions? *Have living things on Earth changed over time? *How have living things on earth changed? *What.

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Presentation on theme: "Evolution. What is evolution? Change over time Questions? *Have living things on Earth changed over time? *How have living things on earth changed? *What."— Presentation transcript:

1 Evolution

2 What is evolution? Change over time

3 Questions? *Have living things on Earth changed over time? *How have living things on earth changed? *What causes living things to change? *How often do the changes happen?

4 The 1 st organisms were probably … prokaryotes single celled Anaerobic Heterotrophic Using RNA as genetic information Similar to the Archaebacteria of today.

5 Evolution of Chemosynthesis …the use of inorganic substances (CO 2 ) as a source to produce organic compounds for energy. These types of organisms probably evolved later than the 1 st heterotrophs.

6 Evolution of Photosynthetic & cell respiration 1 st photosynthetic organisms were probably similar to cyanobacteria. Oxygen is a product of respiration. Oxygen is deadly to anaerobic organisms, some organisms developed mechanisms to use oxygen to breakdown organic compounds (cell respiration!)

7 Cyanobacteria

8 Evolution of Eukaryotes Theory of Endosymbiosis (Endosymbiant Theory) – an organism “invaded” or was ingested/eaten by another and both continued to function, but as a single organism. **Explains the development of mitochondria & chloroplasts!

9 Each new evolutionary step took millions – billions of years. 1 st organism – over 3.5 billion years ago 1 st chemosynthetic org. – about 3.5 billion years ago 1 st photosynthetic organism – about 3 billion years ago (aerobic organisms developed shortly thereafter) 1 st Eukaryote about 2 billion years ago 1 st Multicelled organism – about 1.2 -1.5 billion years ago

10 Each new adaptation was advantageous for the organisms, they thrived and produced more of those organisms.

11 Evidence for Evolution

12 There are 5 pieces of evidence that supports evolution. 1)Fossils 2)Biochemistry 3)Biogeography 4)Embryonic development 5)Anatomy (Morphology)

13 1) Fossils -Remnants of living things from the past -Fossil record shows stratification: things that lived long ago are buried deeper than the more recent organisms. (Law of Superposition)

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15 2) Biochemistry - By looking at DNA sequence we can see which organisms are more closely related.

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17 3) Biogeography -We can compare organisms that live in similar environments in different locations -i.e.: we can compare desert organisms in the US the desert organisms in Africa

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19 4) Embryonic development - In early stages of development there are many similarities between different vertebrates. Some organisms are very similar throughout there embryonic development and are more closely related.

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21 5) Anatomy (morphology) A)Homologous structures – structures that come from a common ancestor B)Analogous structures – structures that have similar function but do not come from a common ancestor C)Vestigial structures – structure that does not seem to have a function, but may have at one time functioned.

22 Homologous structures

23 Analogous structures

24 Vestigial structures


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