EVOLUTION Definition - A gradual change over a period of time

1. EVOLUTIONDefinition - A gradual change over a period of time

3. What is a theory? • Theories are statementsor models that have been tested and confirmed many times • They explain a wide variety of dataand observations • They can be used to make predictions

4. What is a theory? • They are not absolute, they serve as a model of understanding for the world and can be changed as the world view changes • The term "Theory" does not express doubt.

5. Charles Darwin • Naturalist that observed many species • Made many trips to the Galapagos Islands • Observed finches, mockingbirds, tortoises • Wrote the Origin of Species

9. Theory of Evolution by Natural Selection 1. Variation exists among individuals in a species

12. Theory of Evolution by Natural Selection 2. Individuals of species will compete for resources (food and space) called Struggle for Existence (Competition)

13. Theory of Evolution by Natural Selection 3. Some competition would lead to the death of some individuals, while others would survive. This is called Survival of the Fittest

14. Survival of the fittest through Adaptations – Decent with Modifications a) Adaptations are variations that help a species survive and reproduce. b) At first, adaptations are rare. As more of the species survive and reproduce, the number of individuals with the adaptation will increase. c) Other adaptations are inherited behaviors that help an organism find food, protect itself, or reproduce.

15. Theory of Evolution by Natural Selection 4. Individuals that had advantageous variations are more likely to survive and reproduce. Variations come from mutations and sex reproduction. 5. This process he describes came to be known as Natural Selection.

16. What happens to species as the environment changes? • All organisms have traits that allow them to survive in specific environments. • If the environment changes, a species is more likely to survive if it has genetic variation, which results in a variation of traits. • If no individuals have traits that help them to survive and reproduce in the changed environment, a species will become extinct.

17. What happens to species as the environment changes? • Extinction occurs when all members of a species have died. • Greater competition, new predators, and the loss of habitat are examples of environmental changes that can lead to extinction. • Because a natural disaster can destroy resources quickly, organisms may die no matter what adaptations they have. • The fossil record shows that many species have become extinct in the history of life on Earth.

19. Summary of Darwin’s Theory of Natural Selection • Organisms differ; variation is inherited • Organisms produce more offspring than survive • Organisms compete for resources • Organisms with advantages survive to pass those advantages to their children • Species alive today are descended with modifications from common ancestors

20. Evidence Supporting Natural Selection • Fossil Evidence • Comparative Anatomy (Structural) • Embryonic Development • Geographic Distribution • Biochemistry

21. Evidence of EvolutionFossil Evidence • Fossils are remains of once living organisms • Fossils at bottom are older than fossils at top

23. Evidence of EvolutionComparative Anatomy • Homologous Structures - structures that are embryological similar, but have different functions, the wing of a bird and the forearm of a human

24. Evidence of Evolution • Vestigial Structures – structure that lost most or all of function do to lack of use • Examples- Wisdom Teeth and Appendix

26. Evidence of EvolutionEmbryonic Development • Early Embryonic Development is similar which implies they are related, having a common ancestor

27. Geographical Distribution Evidence • Similar organisms from different locations were products of different lines of evolutionary descent

29. Evidence of EvolutionBiochemical • Biochemistry and DNA – by comparing DNA sequences of organisms shows common ancestry

30. Genetic Variation There are two primary sources of genetic variation: • Mutationsare changes in the DNA. A single mutation can have a large effect, but in many cases, evolutionary change is based on the accumulation of many mutations. • SexReproductioncan introduce new gene combinations into a population. This genetic shuffling is another important source of genetic variation

31. Genetic Variation • Genetic variation and the Environment influence Natural Selection • The environment determines which traits are favorable for survival

32. GENETIC RESISTANCE

33. Natural Selection is responsible for Antibiotic Resistance Bacteria and Pesticide Resistance in Foods Antibiotic resistance is the ability of bacteria or other microbes to resist the effects of an antibiotic

35. 10 most dangerous antibiotic-resistant bacteria

36. MRSA

37. Pesticide Resistance  defined as an inheritable genetic change in the sensitivity of a pest population that is reflected in the repeated failure of a product to achieve the expected level of control 

39. Classification of Life • Life on Earth constantly changes. • This process led to Biodiversity. • Biodiversity is the variety of living organisms in a given area. • Biologists have identified and catalogued 1.5 million species so far. • 2 to 100 million additional species yet to be discovered.

40. Why Classify? • To study the great diversity of organism, biologists must give each organism a name. • Taxonomy classifies organisms and assigns each organism a name. • Latin and Greek are languages that would understood by all, so those are the languages that are used for scientific names.

41. Binomial Nomenclature • Carolus Linnaeus, botanist developed two word naming system. • Always in italics, • First word, the genus, is capitalized, second word, the species, is lowercase. • Examples are as follows:

43. Linnaeus’s system of classification

44. Example of classification

45. Traditional Classification vs. Modern Classification • Linnaeus’ classified organisms according to their physical structures and anatomy. • Modern classification classifies organisms according to their evolutionary descent, not just physical similarities. • Let’s think about the dolphin????

47. Dichotomous Key • A device used to easily and quickly identify an unknown organism. • The user of the key is presented with a sequence of choices between two statements based on characteristics of the organism. By always making the correct choice, the name of the organism will be revealed.

48. Here is an example from your book

49. Phylogenetic Treeor Cladogram

50. Phylogenetic Tree • Phylogeny is the evolutionary history of a kind of organism • The tree is a branching diagram or tree showing the evolutionary relationships among various biological species based upon the physical and/or genetic characteristics