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Evolution and Darwin. Evolution Change over time processes earliest forms diversity The processes that have transformed life on earth from its earliest.

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Presentation on theme: "Evolution and Darwin. Evolution Change over time processes earliest forms diversity The processes that have transformed life on earth from its earliest."— Presentation transcript:

1 Evolution and Darwin

2 Evolution Change over time processes earliest forms diversity The processes that have transformed life on earth from its earliest forms to the vast diversity that characterizes it today. Theory-a well-supported testable explanation of events that have occurred in the natural world.

3 Old Theories of Evolution Jean Baptiste Lamarck Jean Baptiste Lamarck (early 1800s) proposed: The inheritance of acquired characteristics passes offspring He proposed that by selective use or disuse of organs, organisms acquired or lost certain traits during their lifetime, which it passes on to its offspring.

4 The Inheritance of Acquired Characteristics Example: Example: A giraffe acquired its long neck because its ancestor stretched higher and higher into the trees to reach leaves, and that the animals increasingly lengthened neck was passed on to its offspring.

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

6 Galapagos Islands

7 Charles Darwin Influences James Hutton James Hutton Proposed that Earth is shaped by geological forces that took place over long periods of time. Proposed that Earth is shaped by geological forces that took place over long periods of time. Thomas Malthus Thomas Malthus Proposed that famine, war and poverty limited human population

8 Charles Darwin Influences Charles Lyell Charles Lyell Darwin led Darwin to realize that natural forces gradually change Earths surface and that the forces of the past are still operating in modern times.

9 Charles Darwin Wrote in 1859On the Origin of Species by Means of Natural Selection Wrote in 1859:On the Origin of Species by Means of Natural Selection Artificial selection-humans selected the genetic variation that they found useful Artificial selection-humans selected the genetic variation that they found useful Proposed a mechanism for evolution: Proposed a mechanism for evolution: NATURAL SELECTION- nature selected the genetic variation that they found useful NATURAL SELECTION- nature selected the genetic variation that they found useful

10 Artificial Selection selective breeding The selective breeding of domesticated plants and animals by man. Question: Question: Whats the ancestor of the domesticated dog? Answer:WOLF Answer: WOLF

11 Natural Selection Individualsfavorabletraits environment Individuals with favorable traits are more likely to leave more offspring better suited for their environment. Cant be seen but results shown Example: Example: English peppered moth (Biston betularia) Biston betulariaBiston betularia - light and dark phases

12 Evolution by Natural Selection Struggle for Existence Members of species regularly compete for food, living space, and other necessities. Survival of the Fittest Fitness: ability of an individual to to survive and reproduce in its environment Adaptation: inherited characteristic that increase an organism chance of survival SURVIVAL OF THE FITTEST-Survive and reproduce the most successfully

13 Struggle for Existence

14 Evolution by Natural Selection Descent with Modification All living organisms are related to one another Common Descent Single Tree of Life All species were derived from common ancestors

15 Intermission

16 Fossil Records

17 Evidence of Evolution 1.Fossil Record: Fossils and the order in which they appear in layers of sedimentary rock (strongest evidence). a.Ancestral traits-primitive features that do appear in ancestral form b.Derived traits-newly evolved features that didnt appear in ancestors

18 Evidence of Evolution 2.Biogeography: Geographical distribution of species.

19 Evidence of Evolution 3.Comparative Anatomy Homologous Structures - Structures that has different mature form but develop from same embryonic tissue. Vestigial structure - Structure that is no longer functioning Analogous structures - Structures that has same mature form but develop from different embryonic tissue.

20 Evidence of Evolution 4. Comparative embryology Study of structures that appear during embryonic development. 5. Molecular biology: DNA and proteins (amino acids)

21 Adaptation Adaptation: a trait shaped by natural selection that increases an organism's reproductive success Fitness: a measure of the relative contribution success of the following generation Types of adaptation Camouflage Mimicry Antimicrobial resistance

22 Summary of Darwin Theory Individual organisms differ and some of the variation is heritable. Individual organisms differ and some of the variation is heritable. Organisms produce more offspring than can survive and many that survive dont reproduce Organisms produce more offspring than can survive and many that survive dont reproduce They will compete for limited resources They will compete for limited resources Each unique organisms has different advantages and disadvantages in the struggle of existence. Each unique organisms has different advantages and disadvantages in the struggle of existence. Individuals best suited to their environment and reproduce most successfully. Individuals best suited to their environment and reproduce most successfully. Species alive today are descended with modification from ancestral species that lived in the distant past Single tree of life. Species alive today are descended with modification from ancestral species that lived in the distant past Single tree of life.

23 Video Darwin: Dangerous Idea


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