NOTES WILL COVER: Evolution Mutations Natural Selection Genetic Variations Adaptations Selective Breeding

Unit 2 :Chapter 10 : Section 3 Evolution Many scientists believe that changes in the plants and animal species on earth can be explained by evolution. Unit 2 :Chapter 10 : Section 3

Theory of Evolution The theory of evolution is the process by which populations accumulate inherited changes over time.

Mutations and Natural Selection According to the theory of evolution, two processes are necessary for populations to change over time. These are mutations and natural selection. Unit 2 :Chapter 10 : Section 3

Unit 2 :Chapter 10 : Section 3 Mutations In order for a population to change, genes must be able to change Genes are made of DNA DNA is made of 4 parts, called nucleotides Unit 2 :Chapter 10 : Section 3

Unit 2 :Chapter 10 : Section 3 Mutations The order of the nucleotides that are put together determines what characteristics you will receive from your parents. Unit 2 :Chapter 10 : Section 3

Unit 2 :Chapter 10 : Section 3 Mutations Changes in the type or order in which these bases appear are known as mutations. Mutations can be harmful, helpful, or not change an individual at all Unit 2 :Chapter 10 : Section 3

Unit 2 :Chapter 10 : Section 3 Natural Selection Natural selection is a word that Charles Darwin made very popular. Unit 2 :Chapter 10 : Section 3

Unit 2 :Chapter 10 : Section 3 Natural Selection According to Darwin’s theory, natural selection says that: “organisms that are better able to survive and reproduce in an environment are more likely to pass their traits on to future generations” Unit 2 :Chapter 10 : Section 3

4 Steps of Natural Selection Overproduction Genetic Variation Struggle to Survive Successful Reproduction Unit 2 :Chapter 10 : Section 3

Natural Selection: Overproduction More individuals are born than will become adults Not all of these baby rats will become adults Unit 2 :Chapter 10 : Section 3

Natural Selection: Genetic Variation The individuals in a population are NOT exactly the same Each has its own set of traits, such as size, color, and the ability to find food Unit 2 :Chapter 10 : Section 3

Natural Selection: Genetic Variation Some traits make an individual more likely to survive and reproduce Other traits make survival and reproduction less likely Unit 2 :Chapter 10 : Section 3

Natural Selection: Struggle to Survive An environment might not be able to support all of the individuals born Also, many individuals are killed by other organisms Only some of the individuals in a population become adults and reproduce Unit 2 :Chapter 10 : Section 3

Natural Selection: Successful Reproduction The organisms that survive and reproduce have traits that are carried on by their many offspring This makes the “good” traits more dominant in the populations of individuals Unit 2 :Chapter 10 : Section 3

Unit 2 :Chapter 10 : Section 3 Practice How are the feathers of peacocks and the bright flowers of some plants related to successful reproduction? The feathers of peacocks attract mates. The bright coloring of some flowers attracts pollinators. Both of these traits increase the chances of successful reproduction. Unit 2 :Chapter 10 : Section 3

Unit 2 : Chapter 14 : Section 2 Animals and Behavior Innate behavior- a behavior that is influenced by genes and does not depend on learning or experience Learned behavior- a behavior that has been learned from experience or observation Migrate- to travel from one place to another Hibernation- a period of inactivity and lowered body temperature that some animals experience in the winter Estivation- a period of reduced activity that some animals experience in the summer Unit 2 : Chapter 14 : Section 2

Unit 2 : Chapter 14 : Section 2 ADAPTATIONS There are some traits among species that help to enhance the survival of those species Animals use many different methods to get food. Chimpanzees use sticks to get ants out of an anthill. This way they can get enough food while using the least amount of energy. Unit 2 : Chapter 14 : Section 2

Unit 2 : Chapter 14 : Section 2 ADAPTATIONS Some animals use camouflage to blend into the environment Some animals can drive other animals away by using external stimuli. Skunks use chemicals as external stimuli. Unit 2 : Chapter 14 : Section 2

Unit 2 : Chapter 14 : Section 2 ADAPTATIONS Many animals are brightly colored and use this external stimulus as warning coloration Often bright colored organisms are poisonous, and predators stay away from them Unit 2 : Chapter 14 : Section 2

Unit 2 : Chapter 14 : Section 2 Animals and Behavior Hibernation, estivation, and migration help many animals survive in harsh conditions. Unit 2 : Chapter 14 : Section 2

Selective Breeding Selective breeding is the process of breeding plants and animals for particular genetic traits Examples: pigeons, dogs, and cattle