Theory of Evolution Descent with Modification
Questions, questions, and one more question What does evolution mean? Genetic change of a population over time. Short or long? Both, can you think of some examples?
Charles Darwin Traveled on the HMS Beagle as the ships naturalist
Darwin s Voyage: HMS Beagle Mission was to chart the coast line of South America. Darwin studied plant and animal life in the different regions of South America.
Charles Darwin Traveled to Galapagos Islands
Charles Darwin Traveled to Galapagos Islands onoticed different islands had different varieties of animals. Tortoises and Finches in particular
Voyage of the Beagle
Landscape of the Galapagos
Galapagos Tortoise
Pinta Island Intermediate shell Fernandina Marchena Pinta James Tower Santa Cruz Isabela Santa Fe Floreana Hood Hood Island Saddle-backed shell Isabela Island Dome-shaped shell
Iguanas of South America
Swimming Iguana
Darwin s Finches
Darwin s Observations on the Beagle Observed that there was a great diversity of life. In Brazil he collected 68 different species of beetles Asked questions like Here is the same environment, but the animals are so different Darwin collected fossils: some he recognized, some he didn t
Things that puzzled Darwin about Galapagos Most of the species Darwin found on the island were found no where else in the world! Where relatives of those organisms found on the main land of South America?
After the voyage Darwin returned to England in 1836. Darwin worked and wrote papers about his findings In 1859 Darwin published his notes as Origin of the Species He proposed a mechanism for evolution: natural selection
Darwin Continued Darwin s finches were separate species He hypothesized that new species could appear gradually through small changes in ancestral species
Darwin Continued Darwin could see this process at work through artificial selection: o Artificial Selection (AKA: Selective Breeding): process of directed breeding to produce offspring with desired traits o Examples: Traits:
Darwin Continued Darwin concluded that, through a competition for resources, some individuals because of their adaptations would be better equipped for survival than others.
LaMarck
Lamarcks Theory Tendency Towards perfection Believe that all organisms become more complex as they evolve. Animals continually change and acquire new traits to help them live more successfully in their environments. Use and disuse Use it or lose it If an animal use a specific body part for a specific function, then that body part would evolve to help that animal in its environment
Giraffes
Lamarcks Theory Tendency Towards perfection Believe that all organisms become more complex as they evolve. Animals continually change and acquire new traits to help them live more successfully in their environments. Use and disuse Use it or lose it If an animal use a specific body part for a specific function, then that body part would evolve to help that animal in its environment Inheritance of Acquired Traits Traits acquired through the use or disuse principle could be passed on to the next generation
Older Darwin and his Book
Natural Selection based on four ideas: 1. Excess reproduction within the species 2. Natural Variation 3. Inheritance 4. Advantages of specific traits in an environment
Theory of Natural Selection Those individuals that possess superior physical, behavioral, or other attributes are more likely to survive in their environment and reproduce offspring.
Peppered Moth
Industrial Revolution
Industrial Evolution
Peppered Moth
Adaptations Camouflage: adaptation that allows species to blend with environment Example: Leafy Sea Dragon (sea horse)
Adaptations Mimicry: one species evolves to resemble another species Example:
Questions, questions, and one more question How do living organisms evolve? Mutations in their DNA: Changes in sequence of nitrogen bases in DNA Genetic Recombination: recombination of pieces of DNA Gene Flow Immigration: flow of organisms into a gene pool Emmigration: flow of organisms out of a gene pool
Genetic drift Genetic drift is the term used in population genetics to refer to the statistical drift over time of gene frequencies in a population due to random events.
Genetic Drift Example: Island of Pingelap and the leader who could not see color (future generations had the same problem. It is very rare)
Speciation Formation of a new species. Takes millions of years What causes new species to appear? Reproductive Isolation over a long period of time. Reproductive Isolation: the inability for a species to breed with related species due to a barrier (such as a geographic barrier, or behavioral differences)
South Rim Albert
North Rim Kiabab
Evidence of Evolution 5 Factors: 1. Fossils
Evidence of Evolution 5 Factors: 1. Fossils 2. Geographic Distribution
Geographic Distribution Beaver NORTH AMERICA Capybara Muskrat SOUTH AMERICA Beaver Muskrat Beaver and Muskrat Coypu Capybara Coypu and Capybara Coypu
Evidence of Evolution 5 Factors: 1. Fossils 2. Geographic Distribution 3. Homologous body structures 4. Vestigial Structures
Vestigial Organs Structures that once served a purpose but now have no function Human appendix, whale pelvis bone, hind claws of the python
Evidence of Evolution 4 Factors: 1. Fossils 2. Geographic Distribution 3. Homologous body structures 4. Vestigial Structures 5. Similarities in early development
Turtle Mouse Human Chicken Pig
Evolution Pop Quiz
1. Who observed variations in the characteristics of animals and plants on the different islands of the Galapagos? a. James Hutton b. Charles Lyell c. Charles Darwin d. Thomas Malthus c. Charles Darwin
2. Fitness is a result of a.adaptations b.artificial selection c.common descent d.variation a. adaptations
3. A vestigial organ is a. A tiny cellular projection on the surface of other organs b. Organs that serves no useful function in an organism c. An organ found only on the ventral side of an animal d. An organ that provides a better level of fitness for an organism a. Organs that serves no useful function in an organism
4. An inherited characteristic that increases an organism s ability to survive and reproduce in it s specific environment is called a.a vestigial organ b.adaptation c.speciation d.radiation b. adaptation
5. Larmarck believed that organisms had a tendency toward a. Natural variation b. Artificial selection c. Descent with modification d. Perfection and complexity d. Perfection and complexity
7. Which of these reasons is NOT a reason for considering Larmarck s theory to be incorrect? a. Larmarck did not realize that organisms are adapted to their environment. b. Larmarck did not realize that an organism s behavior has no effect on its inheritable characteristics. c. Larmarck did not realize that traits are inherited. d. Larmarck believed that an organism could alter its body structure lifetime and pass those chances on to its offspring. a. Larmarck did not realize that organisms are adapted to their environment.
9. Which is NOT evidence of evolution? a. The fossil record b. Acquired traits c. Geographic distribution of living species d. Homologous body structures b. Acquired traits
10. Darwin s theory of evolution is based on a. A tendency toward perfect organisms b. Transmission of acquired characteristics c. Natural variation and natural selection d. Use and disuse c. Natural variation and natural selection