Unit 8 Organization of Life, Plants, and Evolution

1. Unit 8Organization of Life,Plants, and Evolution

2. What is Evolution? • Darwin’s Theory of Evolution (Chapter 15) • A. Charles Darwin • In 1831 Charles Darwin took a trip to the Galapagos Islands as a naturalist aboard • the HMS Beagle. This trip took 5 years, and allowed him to see and collect • collections of animal species. • What evidence led Darwin to develop the theory of natural selection and common descent to explain evolution? • Similiarities between fossils, the relationships between finches and tortoises on the different islands.

6. B. Natural Selection • Darwin’s Theory of Evolution is based on the mechanism of • Natural selection. • Artificial Selection is what happens when humans choose who breed and survive. • Natural Selection is what happens when only the most fit survive and • nature determines who will breed and survive. • The Four principles of Natural Selection include:

7. 1. Variation - Organisms in a population are different from one another • 2. Heritability - Traits are passed from parent to offspring • 3. Overproduction – Populations produce more offspring than can survive, this creates competition for resources. • 4. Reproductive Advantage – Variations make some organisms of a species more likely to reproduce and have more offspring than others.

8. Evolution means to change over time. • C. Evidence of Evolution • Darwin’s theory states that evolution is a result of natural selection • Evidence includes: • 1. The Fossil Record – allows scientists to study and compare traits. • a. Derived traits – newly evolved/different traits found in organisms • b. Ancestral traits – traits similar between ancestor and modern day organisms. • c. Radioactive Isotopes- used to track the age of fossils

9. Comparative Anatomy – Related structures between organisms. • a. Homologous Structures - Similar structures inherited from a common ancestor • Example – animal forelimbs • b. Vestigial Structures – Structures that have reduced or lost function • Examples – snake pelvis, kiwi wings, human appendix • c. Analogous Structures – Similar structures inherited from unrelated species • Species- not from common ancestors. • Examples – eagle/beetle wings

10. Divergent Evolution Ex:

12. Convergent Evolution

13. 3. Comparative Embryology – Similarities between vertebrate embryos. • 4. Comparative Biochemistry – Similar enzymes, amino acids, DNA, RNA, and other molecules • 5. Geographic Distribution - Related organisms share geographical distribution • D. Adaptation • An adaptation is a trait that increases an organism’s fitness • Fitness – the measure of an organism’s ability to make reproductively viable offspring

15. Adaptations include: • 1. camouflage - to blend with environments. • 2. Mimicry - to resemble other species • 3. Antimicrobial resistance to be immune to antibiotics

16. **Remember, and Allele is one of the two traits given by an offspring's parents. It is one letter in a genotype: • Bb-B dominant allele and b-resesive allele

17. E. Mechanisms of Evolution • In addition to natural selection other mechanisms affect evolution. • These include: • 1. The Hardy-Weinberg principle – allele frequencies stay • Constant, a population is in genetic equilibrium. • Example- Screech owls come in two colors: Brown and Gray. • Since the number of alleles that code for brown and gray are the same, • there is an equal proportion of brown and gray screech owls in a population

18. Hardy-Weinberg Principle

19. 2. Genetic Drift-change in allele populations due to chance (Random reception of alleles from Mom and Dad • Example- A group of butterflies comes in two colors: blue and brown. • The brown butterflies die out, leaving only blue butterflies to pass on their alleles to the next generation

20. Sulfur Butterflies

21. 3. Founder Effect-a small population settles in an area and is separated from the larger population • Example: Galapagos Finches settled on different islands and developed different characteristics

23. 4.Bottleneck-when populations decline to very small numbers and then rebound, several traits may disappear in the population • Example- Northern Elephant Seals over a period of time many died out • and when the population made a comeback, there was less genetic diversity

24. 5. Gene Flow-When individuals from other areas migrate into a population, the genetic diversity of the population increases. • Example-A Species of Bird that is blue colored, has an individual migrate in that is red colored.

25. 6. Nonrandom Mating: Selecting a mate for particular traits that are found desirable. • Links Closely with Sexual Selection: • Example Peacock, Antlers on a deer, and Male Frigate Bird

26. 7. Mutation-changes in a genetic code that occur randomly • Example-Antibiotic resistance in bacteria

27. Types of selection: • 1. Directional Selection- when there is pressure for resources, the population moves towards a certain trait to adapt: Ex: Giraffe Necks • 2. Stabilizing Selection- eliminates the extremes of a population: Ex: Rabbits with long legs and short legs • 3. Disruptive Selection- Eliminates the “average” selection for organisms in favor of the extremes. Ex: Acorn size

28. 4. Sexual Selection-selection of organisms with sexually attractive traits: (Ex. Deer antlers) • 5. Balanced selection (polymorphism)-genetic equilibrium has occurred: No evolution occurs.

29. Reproductive Isolation – Prevents groups of organisms from Reproducing • Speciation - Causes a population to diverge and split into two separate species. • 1. Allopatric - a physical barrier-prevents species from mating • Examples-Two species of squirrel separated by the grand canyon

30. 2. Sympatric - no geographic barrier-individualspecies evolve from common ancestors in the same location • Examples-Species of fruit flies have evolved to feed on different apples in the same regions:

31. Patterns of Evolution • 1. Adaptive Radiation (also known as divergence) • One species gives rise to many • Example –different finch species adapt to different habitats • 2. Coevolution - a species has a close relationship with other species • Example – orchids/moths, sharks/remoras, etc. • 3. Convergent Evolution - 2 unrelated species become similar • Example – placental and marsupial animals

33. Adaptive Radiation

34. Co-Evolution

35. Convergent Evolution

36. F. Sexual Reproduction vs. Asexual Reproduction- • Sexual Reproduction gives an evolutionary advantage to organisms because it gives them diversity. • Example: immune systems develop in response to new experiences with microbes and evolves with each experience.

37. Genetic Isolation is the prevention one species from mating with another: • 1. Llama and Camel

38. 2. Polar Bear and Brown Bear

40. 3. Cheetah and Leopard

41. 4. Fox Squirrel vs. Black Squirrel

42. Archaeopteryx

43. Terror Birds

44. Cuttlefish camouflage

45. Something to think about • If it takes many years for species to evolve than is it individuals or populations that evolve? • Populations: It takes an individual with certain adaptations and many generations for the adaptation to evolve in the population. • In the end natural selection can be simply defined as: • Bono is from an island that consists of 200 people, from what you learned, what are some assumptions that you can make about Bono and the rest of the people on his island compared to that of someone from New York City.

46. Classification of Living Things • The study of life is Biology • Draw the kingdom of science, and how each area of science is related.

47. Biology and the Animal Science • The science of grouping organisms on the basis of their similarities is called • Taxonomy • Aristotle (350 BC) was the 1st to subdivide into two groups: Plants and Animals • Aristotle’s system lasted 2000 years

48. Carleus Linnaeus developed a new system based on 7 groups: • 1. Kingdom 2. Phylum • 3. Class • 4. Order • 5. Family • 6. Genus • 7. Species

49. Most animals are now referred to by their • Genus and Species • This is called their • Scientific Name and is a practice known as • Binomial nomenclature • Examples: • Homo sapiens , Humans : Canus lupus: Domestic Dogs

50. Organisms also have a Common name, which can sometimes cause a great deal of confusion such as mountain lion: puma, cougar, panther, catamount or starfish silverfish, jelly fish (none of which are fish). • Modern taxonomists now group according to chromosome structure, reproductive potential, biochemical similarities, embryology, and evolutionary relationships. • Members of the same species that differ in some important way are called subspecies • Linnaeus divided according to two kingdoms: • Plant Kingdom (autotrophs) • Animal Kingdom (heterotrophs)