* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download change over time
Survey
Document related concepts
Natural selection wikipedia , lookup
The Descent of Man, and Selection in Relation to Sex wikipedia , lookup
Organisms at high altitude wikipedia , lookup
Population genetics wikipedia , lookup
Evidence of common descent wikipedia , lookup
Evolving digital ecological networks wikipedia , lookup
Saltation (biology) wikipedia , lookup
Transitional fossil wikipedia , lookup
The eclipse of Darwinism wikipedia , lookup
Hologenome theory of evolution wikipedia , lookup
Transcript
CH.15 DARWIN’S THEORY OF EVOLUTION 15.1 Life’s Diversity 1. Evolution – change over time; the process by which modern organisms have descended from ancient organisms. (scientific theory) 2. Voyage of the Beagle: Charles Darwin – joined the H.M.S. Beagle in 1831 and made observations that led him to a hypothesis about the way life changes over time. 3.Fossils – Darwin collected fossil evidence - the remains of ancient organisms. Some of those fossils resembled organisms that were still alive. Others looked unlike any creature he had ever seen. 4.Galapagos Islands – He was fascinated by the land tortoises, marine iguanas and finches. 15.2 Ideas That Shaped Darwin’s Thinking Lamarck – a French naturalist. a. In 1809, he published a hypothesis that by selective use or disuse of organs, organisms acquired or lost certain traits during their lifetime. b. These traits could be passed through offspring and eventually leads to change in a species. Ex/ Ancestors of birds acquired an urge to fly. Over many generations, the birds kept trying to fly and their wings increased in size and became more suited to flying. -Use and Disuse – organisms can alter the size or shape of particular organs by using their bodies in new ways. c. Ex/ Trying to use their limbs for flying, eventually transformed the limbs into wings. If a winged animal did not use its wings, the wings would decrease in size over generations and finally disappear. -Inheritance of Acquired Traits – acquired characteristics could be inherited. All the changes made, it would pass those changes to its offspring. d. Ex/ If you spent your lifetime lifting weights, your children would inherit big muscles. Problem: Answer the following questions: In the 1800s, the Irish solved their problem of feeding a growing population by planting potatoes. Specifically, they planted the "lumper" potato variety. And since potatoes can be propagated vegetatively, all of these lumpers were clones, genetically identical to one another. The lumper fed Ireland for a time, but it also set the stage for human and economic ruin. Evolutionary theory suggests that populations with low genetic variation are more vulnerable to changing environmental conditions than are diverse populations. The Irish potato clones were certainly low on genetic variation, so when the environment changed and a potato disease swept through the country in the 1840s, the potatoes (and the people who depended upon them) were devastated. 1) In 1846, 100% of the potato crop was killed by a single fungus. Why? 2) Why does cloning compromise the potato’s genetic variation? 3) How would the fungus affect a wild population of potatoes? Why? 15.3 Genetic Variation 1. Darwin – how could the wren, warblers and blackbirds all be descendents of a finch? a. His idea abandoned the idea that a species is perfect and unchanging and argued that natural variation explained the mechanism of change. 2. Natural Variation – the differences among individuals of a species, found in all types of organisms. Ex/ Antibiotics + Bacteria, Ex/ Humans + Bubonic Plague 3. Artificial Selection – or selective breeding, is when breeders use variation to improve crops and livestock. Ex/ Cows + milk a. Q – Give an example of how we use selective breeding today. 4. Struggle for Existence – artificial selection works in nature. Ex/ predators vs. prey 5. Survival of the Fittest – the ability of an individual to survive and reproduce in its specific environment (adaptations). 6. Adaptations – is any inherited characteristic that increases an organism’s chance for survival. Ex/ porcupines or feathered seeds 7. Genetic Variation – each individual differs from other members of its species, unique advantages and disadvantages. 8. Natural Selection – because some species do better in their environment, they go on to reproduce and fit in their environment. a. Give an ex/ of genetic variation: 9. Common Descent – All species – living and extinct – were derived from common ancestors. A single “tree of life” links all living things. Evidence of Evolution includes The fossil record Geographic distribution of living species Homologous body structures Similarities in early development which is composed of which indicates which implies which implies Physical remains of organisms Common ancestral species Similar genes Similar genes 10. Fossil Record – the evidence of physical remains 11. Geographic Distribution – similar animals in different locations that are from different times of descent. Ex/ 12. Homologous structures – anatomical similarities among the body parts of animals with backbones. a. Vestigial Organs – Ex/ Whale b. Embryology – early stage embryos Ex/ chickens, turtles, rats look similar. Beaver NORTH AMERICA Beaver Muskrat Muskrat Beaver and Muskrat SOUTH AMERICA Coypu Capybara Coypu and Capybara Capybara Coypu Ex/ Which two are the closest in relation?