Thursday, June 4, 2015 HOMEWORK: Evolution Test June 10,11,15,16 OBJECTIVE: I will be able to explain how natural selection leads to evolution by discussing the mechanisms of natural selection used in the models I made DO NOW: Turn in Peacock model (Doc#19) No HW=Pink slip! What are the 5 steps of natural selection?

Natural Selection Model The initial population varies in many traits. Individuals have one version of some traits. An environmental change occurs. Individuals with one version of a trait are more likely to survive after the environmental change. The trait is advantageous in the new environment. The individuals that survive more reproduce more. Their offspring vary but are similar to them. So more offspring have the advantageous version of the trait. After many generations, the population still varies, but most individuals have the advantageous version of the trait.

Doc # – Graphic Organizer Graphic organizer You can write your notes in short hand, copy what you feel is important Text pg (Natural Selection Pressures) Text pg (Evidences of Evolution) I will be able to explain how natural selection leads to evolution by discussing the mechanisms of natural selection used in the models I made

Natural Selection Overproduction Variation Competition Selection Environmental Change Genes

Overproduction – Most species produce more offspring than can possibly survive (example: spiders, many eggs at one birth) – There is not enough food, water & living space for all of them, creates a struggle among offspring – The “best” or strongest survive & those who are better able to then pass on their genes Doc # – Natural Selection I will be able to explain how natural selection leads to evolution by discussing the mechanisms of natural selection used in the models I made

Variations – Members of same species have different traits Look around the rooms – different hair – Variation – any difference between individuals of the same species – Examples – humans (blood type, skin color), bugs (color), cheetahs (speed) I will be able to explain how natural selection leads to evolution by discussing the mechanisms of natural selection used in the models I made

Competition – Food, space, territory, & resources are limited in nature; members of a species compete to survive – Not always physical, usually indirect Example – trees compete for sunlight – A smaller tree will receive less sunlight than an adjacent tree which is larger than it in a rainforest. The larger tree is competing with the smaller one for the same sunlight I will be able to explain how natural selection leads to evolution by discussing the mechanisms of natural selection used in the models I made

Selection – Some variations make individuals better adapted, those individuals are more likely to survive & reproduce – Offspring may inherit the helpful characteristics, making them more likely to survive and pass on traits – After many generations more members of the species will have this trait – The environment selects the organisms with helpful trait to become a parents of next generations – Helpful variations may accumulate in a species while unfavorable ones may disappear. – Examples: giraffes with long necks I will be able to explain how natural selection leads to evolution by discussing the mechanisms of natural selection used in the models I made

Environmental Change – Change in environment can affect an organism’s ability to survive; therefore, can lead to natural selection – Example: monkey flowers do not grow in soil with high concentrations of copper; however, after some of them have a variation to survive in soil with copper, those plants will be the ones to reproduce & over many generations monkey grass in that location can grow in soil with high copper I will be able to explain how natural selection leads to evolution by discussing the mechanisms of natural selection used in the models I made

Genetics – Where do variations come from? – This originally could not be explained – Scientists later discovered variations occur from changes in our genes – We get genes randomly from both parents so probability of genetics plays a role (Think Punnett Square and Pedigrees) – Only genes that are inherited can be part of natural selection I will be able to explain how natural selection leads to evolution by discussing the mechanisms of natural selection used in the models I made

Complete figure 5 pg 244 I will be able to explain how natural selection leads to evolution by discussing the mechanisms of natural selection used in the models I made Sample: Variation Each turtle has slightly different traits. Some may be protected by harder shells.

Complete do the math pg 246 I will be able to explain how natural selection leads to evolution by discussing the mechanisms of natural selection used in the models I made

Closure In addition to survival, what else must happen for natural selection to affect the evolution of the species? – The individuals that survive must reproduce and pass on their adaptations to their offspring I will be able to explain how natural selection leads to evolution by discussing the mechanisms of natural selection used in the models I made