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Chapter 15 Theory of Evolution.

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1 Chapter 15 Theory of Evolution



4 Objectives CLE Explain how genetic variation in a population and changing environmental conditions are associated with adaptation and the emergence of new species. SPI Recognize the relationships among environmental change, genetic variation, natural selection, and the emergence of a new species.  Explain how natural selection operates in the development of a new species

5 Objectives CLE Summarize the supporting evidence for the theory of evolution. SPI Apply evidence from the fossil record, comparative anatomy, amino acid sequences, and DNA structure that support modern classification systems.  Associate fossil data with biological and geological changes in the environment.

6 Objectives Check210.Inq.1 Trace the historical development of a scientific principle or theory, such as cell theory, evolution, or DNA structure

7 Evolution The process of change in the inherited characteristics within populations over generations such that new types of organisms develop from preexisting types. The processes that have transformed life on earth from it’s earliest forms to the vast diversity that characterizes it today. A change in the genes!!!!!!!!

8 The inheritance of acquired characteristics
Proposed by Jean Baptiste Lamarck (early 1800’s) by using or not using its body parts, an individual tends to develop certain characteristics, which it passes on to its offspring.

9 The inheritance of acquired characteristics

10 Catastrophism George Cuvier
Geologist Noted that fossilized organisms differed greatly than current Sudden catastrophes had caused the extinction of groups tag/geology/

11 Uniformitarianism Charles Lyell
natural forces gradually change Earth’s surface and that the forces of the past are still operating in modern times Influenced Darwin’s ideas

12 Darwin’s Voyage

13 Charles Darwin Darwin set sail on the H.M.S. Beagle ( ) to survey the south seas (mainly South America and the Galapagos Islands) to collect plants and animals. On the Galapagos Islands, Darwin observed species that lived no where else in the world. These observations led Darwin to write a book.

14 On the Origin of Species by means of Natural Selection
Published 1859 Two main points: 1. Species were not created in their present form, but evolved from ancestral species. 2. Proposed a mechanism for evolution: NATURAL SELECTION

15 Natural Selection Individuals with favorable traits are more likely to leave more offspring better suited for their environment. Also known as “Differential Reproduction” Example: English peppered moth (Biston betularia) - light and dark phases

16 Natural Selection Organisms in a population adapt to their environment as the proportion of individuals with genes for favorable traits increases. Those individuals that pass on more genes are considered to have greater fitness.

17 Natural Selection

18 Artificial Selection The selective breeding of domesticated plants and animals by man.

19 Artificial Selection

20 Evidence of Evolution 1. Biogeography:
Geographical distribution of species. the study of the locations of organisms around the world, provides evidence of descent with modification.

21 Evidence of Evolution 2. Fossil Record: Fossils and the order in which they appear in layers of sedimentary rock (strongest evidence). The fossil record shows that the types and distribution of organisms on Earth have changed over time. Fossils of transitional species show evidence of descent with modification.

22 Fossil Record

23 Fossil Record Transitional Species
Fossils of transitional species show evidence of descent with modification.

24 Evidence of Evolution 3. Homologous structures:
Structures that are similar because of common ancestry (comparative anatomy)

25 Evidence of Evolution 4. Comparative embryology
Study of structures that appear during embryonic development.

26 Evidence of Evolution 5. Vestigial structures
Structures that are not used in current form

27 Evidence of Evolution 6. Molecular biology
DNA and proteins (amino acids) - the subunit sequences of biological molecules such as RNA, DNA, and proteins indicates a common evolutionary history.

28 Molecular biology: Hemoglobin

29 Case Study: Caribbean Anole Lizards
Ongoing examples of evolution among living organisms can be observed, recorded, and tested. In convergent evolution, organisms that are not closely related resemble each other because they have responded to similar environments.

30 Case Study: Caribbean Anole Lizards
Divergence and Radiation In divergent evolution, related populations become less similar as they respond to different environments. Adaptive radiation is the divergent evolution of a single group of organisms in a new environment.

31 Natural Selection of Anole Lizard Species

32 Convergent Evolution Species from different evolutionary branches may come to resemble one another if they live in very similar environments. Example: 1. Ostrich (Africa) and Emu (Australia). 2. Sidewinder (Mojave Desert) and Horned Viper (Middle East Desert)

33 Coevolution Evolutionary change, in which one species act as a selective force on a second species, inducing adaptations that in turn act as selective force on the first species. Example: 1. Acacia ants and acacia trees 2. Humming birds and plants with flowers with long tubes 3. Antibiotic resistance among bacteria

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