Evolution

1. Evolution Brianna Manuel, Emma Page Stacia Paglieri and Georgia Pullis

2. Charles Darwin • Charles Darwin discovered the beginning of evolution. In his theory, he had an idea that animals could change through time. • Darwin found that different birds could have different beaks depending on where they lived and what type of food they ate. • He soon realized that species of animal can change through time, according to the animals environment.

3. Darwin’s Journey • In 1831 Charles Darwin set off on a scientific expedition on the ship H.M.S. Beagle • During the five-year trip, Darwin took notes and a few special specimens for later studying • He was most successful on his visit to the Galapagos Islands • After the voyage Darwin discovered he had collected different varieties of the same species • He came up with a theory of evolution

4. Darwin’s Theory • A species is a population of organisms that breed with each other to produce more offspring. • Living organisms have been passed down modifications from those, in the species, that have lived before them. • Natural selection is the explanation of evolution.

5. Natural Selection • Natural selection is when types of animals in a species die because they are not able to live in the environment. Therefore, the surviving organisms pass down traits to their offspring for survival. • Resources may be limited because of over-reproducing of organisms. There is competition for resources such as shelter and food.

6. Natural Selection • Individuals in a population have different traits and some of these traits are passed on to offspring if they are traits that offer success. • Some organisms are more adapt to survival than others because of mutations that have been passed on. • Those who are able to survive pass on their genes to their offspring; those who are not able to survive become extinct.

7. Evidence of Evolution • Homologous Structures: • Similarities in ancestors • Analogous Structures: • Similarities in looks and functions • Vestigial Structures: • Helpful functions for ancestors, but not for modern organisms

8. Embryology Similarities: • Different embryo’s show similarities proving they originated from the same ancestors • Macromolecules Similarities: • The more similar a species homologous proteins, the closer the species’ are

9. Isolation • Isolation happens when two parts of a interbreeding population stop interbreeding. There are two specific types that create species’. • Geographic Isolation: • The physical separation of populations such as by climate change • Reproductive Isolation: • Barriers between breeding of a population in a certain area

10. Fossils • Fossils trace old, dead organisms, often found in sedimentary rock and formed by sediment • Sediment is made out of things like dust, sand or mud, which is deposited by wind or water • Fossils give us evidence of past organisms and how they evolved to be the modern organisms that we see today.

11. Patterns of Evolution • There are many ways that animals can change to adapt to their habitats and the pattern. • The speed of this change depends on the changes in the environment. • When there is a change within a species that is in close association with one another, it is called co evolution. Predators and prey often co evolve with each other. An example is animals that pollinate the plants.

12. When organisms appear to be closely related but are actually different from each other, it is called convergent evolution. • Convergent evolution happens when the environment selects similar phenotypes, even though the ancestors were very different from each other. • An example is sharks and porpoises. Sharks are fish and porpoises are mammals, but their features are similar and they share the same environment.

13. When two or more related species become more and more dissimilar, it is called divergent evolution. • Divergence is usually a result of differing environments. It can eventually result in making a new species. • Adaptive radiation is one important type of divergent evolution. This is when many species evolve from a single ancestral species. Darwin discovered this when he studied the Galapagos tortoises. • Artificial selection is when the process of divergence is sped up artificially. An example is how different dogs are bred by humans.

14. Variation in Traits • Within a population, the observable traits of an individual can vary. For example, in a population of fish, the fish can vary in size. • In populations, things like height and weight tend to show a variation pattern in a bell curve. • Biologists can study the variation of traits within a population by measuring that trait in a large sample.

15. Causes of Variation • Variation can be influenced by environmental factors like the amount and quality of food. It is also influenced by heredity. • Parents produce several children, but all are different. Variation is found among the children, who have varying genes. Generations of species can look similar, but they have differences.

16. Variation in genes can happen in three ways • Mutation: this is a result from flawed copies of individual genes. • Recombination: this is the reassociation of genes in a certain individual. This occurs during meiosis. • The random fusion of gametes: this is mostly a game of chance by individual gametes. There are millions of sperm involved in mating and it is just a matter of chance which one fertilizes the egg. This process makes sure that offspring are not complete copies of their parents.

17. The Question • Where do the species on Earth come from and what is the role of extinction? • There are many theories about how life began, but the world is ever-changing and new species are always being found. These species have evolved from past species through mutation. This is evolution. Evolution is how the species eventually change there observable traits to adapt to their ever-changing environment.

18. Extinction is a major part of evolution. • Many of the ancestors of species are now extinct because they were not fit to survive their environment. These ancestors helped in the process of evolution. Before they became extinct, they created a new generation. This generation was mutated by the different genes of the parents and made more fit to survive the environment. • Extinction is important to evolution because, to make new species that can survive our environments, old species need to die out.

19. Evolution with the Earth • Our starship earth is very important to us. We need all of our animals to survive and keep the circle of life in motion. • Evolution brings us the best of certain species of animals and they become the best in the best of ways. Through natural selection, earth chooses her own inhabitants. We as humans are lucky to be a part of the Earth as we know it. We are even a part of evolution.

20. Sources • http://www.tutornext.com/system/files/u81/chapter%209-final-9.gif • Modern Biology– Holt, Rinehart and Winston • All pictures are from google