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TOPIC : Evolution AIM : Explain the theory of Natural Selection. Do Now : 1. Take out your Natural Selection Reading Notes. 2. Next slide HW : Castle Learning due Tuesday. Human gene for clotting factors. 1. Identify structure Y. 2. Identify process X. 3. Identify structures Z.
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TOPIC: Evolution AIM: Explain the theory of Natural Selection. Do Now: 1. Take out your Natural Selection Reading Notes. 2. Next slide HW: Castle Learning due Tuesday
Human gene for clotting factors 1. Identify structure Y. 2. Identify process X. 3. Identify structures Z. 4. Identify the process represented in the diagram. Bacterial DNA Y Recombinant DNA Bacteria that produce clotting factors Z Process X Mitosis
What are the genotypes of the individuals from generation 1? HETEROZYGOUS
3. What are the genotypes of the parents in generation 3? HETEROZYGOUS
1. According to this evolutionary tree, which species is the common ancestor? 2. Which 2 species are most closely related? a. Flatworms and Sponges b. Mollusks and Annelids c. Annelids and Arthropods d. Rotifers and Cnidarians 3. Which species is more complex? a. Protists b. Rotifers c. Echinoderms d. Mollusks Protists
Lamarck • First person to propose a theory of evolution. • Inheritance of acquired traits. • Theory of use and disuse.
Weismann • Acquired characteristics are NOT passed on to offspring • Cut off the tails of mice for 22 generations • Offspring born with tails
Charles Darwin 1830’s Studies on Galapagos Islands
Natural Selection 5 main points: Overproduction Variation Survival of the fittest Competition Speciation
1. One of the prime motives for all species is to reproduce and survive, passing on the genetic information of the species from generation to generation. When species do this they tend to produce more offspring than the environment can support. OVERPRODUCTION
2. Darwin noted many differences in the specieshe observed on his trip to the Galapagos Islands. VARIATION
Ex: Polar bears with thicker fur • Darwin wasn’t able to explain where variations came from
3. The lack of resourcesto nourish these individuals places pressure on the size of the species population, and the lack of resources means an increased strugglebetween these organisms, and as a consequence, some organisms will not survive. COMPETITION
4. The organisms that die as a consequence of this competition were not totally random. Darwin found that those organisms more suited to their environment (those with favorable traits or adaptations) were more likely to survive. SURVIVAL OF THE FITTEST
5. Overtime, the offspring of individuals with helpful adaptations make up more of a population and eventually may become a separate species. SPECIATION
Darwin observed a 13 species of finches that were all similar except for differences in body size, beak shape and eating habits.
2. Describe the reason why organisms do not survive, according to Darwin. • Less suited organisms are “weeded out” because they lack favorable adaptations.
3. Identify an example of a favorable adaptation that you have observed in a species.
Ducks are birds that have waterproof feathers. They live on a pond and on land.
Kangaroos • Habitat: Dry inland Australia, including deserts and grasslands • Adaptations: • They are able to go with out drinking as long as green grass is available and it adapts well to drought. • They can hop as fast as 40 mph (64 km). They use this as their first line of defense. • The tail serves as a balance when the animal leaps and as a prop when it stands.
4. Why does Darwin believe organisms “evolve?” • They evolve to suit their environment (where they have a better chance of survival)
5. State Darwin’s Theory of Natural Selection. • Organisms with favorable adaptations will survive, reproduce, and pass on the trait to offspring. • Organisms with unfavorable adaptations will not survive.
Overproduction Competition Survival of the Fittest Speciation
NATURAL SELECTION Let’s summarize… • Identify the name of Darwin’s theory of evolution. • What organism did he observe at the Galapagos islands? • According to Darwin, which organisms survive? Why? • Identify that Darwin does not explain. • Why do organisms compete? • What makes an organism “most fit” to survive? 7. Which process involves one species evolving into many species overtime? FINCHES THOSE WITH FAVORABLE ADAPTATIONS. THEY ARE BETTER ABLE TO SURVIVE. VARIATION FOR RESOURCES THEY HAVE A FAVORABLE ADAPTATION SPECIATION
1. Identify the finch that lives on an island with fruit as the main source of food. Support your answer. Vegetarian finch They have parrot-like beaks. 2. Identify the finch that lives on an island with cacti as the main source of food. Support your answer. Cactus ground finch They have probing bills.
3. Describe what occurs on an island inhabiting small ground finches and medium ground finches. The finches will compete for food. 4. Can vegetarian finch and large ground finches inhabit the same island? Support your answer. Yes. They eat different types of food.