HAPPY TUESDAY Bellwork: Write down only the bolded red portion and your answer. Two species of mice live in a field in the middle of East Texas. One mouse species is WHITE with BLACK spotting. The other is BROWN with WHITE spotting.After a year, the population of white mice has dramatically decreased, while the population of the brown mice has slightly increased. Why would this be happening? Please also have a pen or pencil and your journal or paper ready.

Standard: (7E)Analyze and evaluate relationship of natural selection to adaptation. Essential Question: How does evolution happen?

What is Evolution?

Evolution: change in heritable traits of a population across generations (over time).

Evolution is called “the grand unifying theory of biology.” Evolutionary theory continues to change as new data are gathered and new ways of thinking arise.

A gene pool is the total number of genes of every individual in an interbreeding population.

Evolution can also be defined as a change in the gene pool over time.

What important contribution did Charles Darwin make to biology?

Charles Darwin: contributed more to our understanding of evolution than anyone else. Darwin traveled, made observations and collected evidence that led him to propose his revolutionary process in a book called Origin of the Species.

Mechanisms of Evolution (How does evolution happen?)

There are 5 factors that can affect the frequency of a gene in the gene pool. 1.Genetic Mutation 2.Non-random mating 3.Natural Selection 4.Small Population 5.Gene Flow

1. Genetic Mutation: Changes in DNA that happen due to errors in replication, transcription, translation, or because of environmental factors. – The source of all new genes/traits in a population

If mutations are passed on to offspring (over generations), then evolution has occurred

2. Non-Random Mating Not all mates are created equal. In many species, mates are chosen for specific characteristics. Many organisms compete for mating rites. Strong and good-looking organisms are typically favored. This limits the size of the gene pool

3. Natural Selection survival of the fittest advantageous genes are passed on to the next generation while harmful genes are eliminated the driving force of evolution

Examples of natural selection

Why does natural selection happen?

Population size is limited by environmental resources

Fitness: the ability of an organism to survive and reproduce. Fitness is the result of adaptations.

Adaptation: any inherited characteristic that increases an organism’s chance of survival.

Successful adaptations: - enable organisms to become better suited to their environment - increase an individual’s ability to survive and reproduce. Humans have thousands of adaptations: large brain, opposable thumbs, excellent sensory organs, light, strong skeleton, etc.

Bunny Simulation If only one species is considered the "fittest", why do we still have so many variations among species. Why do some birds have very long pointy beaks, while other birds have short flat beaks?

Debrief Options Create a chart on the bunny simulation What are adaptations that can help the wolf survive? Quickwrite answering Essential Question.

Homework: Watch “Natural Selection” by Stated Clearly Write a 3 sentence summary of the concept of natural selection Write a 3 sentence opinion of the concept of natural selection Give one example of natural selection

Summary of Darwin’s Theory:  Individual organisms differ and some of these variations are heritable (passed on)  Organisms produce more offspring than can survive and many that do survive do not reproduce  Because more organisms are produce than can survive, they must compete for limited resources (food, shelter, etc)  Each unique organism has different advantages (good) and disadvantages (bad)  Individuals best suited to their environment survive and reproduce successfully  These organisms that survive pass their heritable traits to their offspring

Summary of Darwin’s Theory cont’d:  Other individuals that are not suited for their environment die or leave few offspring  This process called natural selection causes species to change over time  Species alive today are descended with modification from ancestral species (their ancestors)  This process by which diverse species evolved from a common ancestor unites all organisms on Earth into a single tree of life

What to do: 1.Check you grade in the back. 2.Figure out which of the assignments you need to make up. 3.Get the assignment. 4.When finished, turn it in to you class period tray. IF YOU HAVE NOTHING TO MAKE UP: Congratulations! You won a trip to space! You are going to Mars to study the organisms that live there. When you arrive you observe 2 new species. Using the basic characteristics of Mars, create the two species you encounter with adaptations that are appropriate for life on Mars. Write 5 sentences describing the organisms and draw a picture of them on Mars. Basic Characteristics of Mars: Diverse terrain, including: mountains, valleys, polar ice caps, deserts Atmosphere has clouds, thus rain The red color is due to blowing sand Has vegatation It is VERY cold.