Agenda. Warm-up: Look in your notebook for your grades. Review Notes on Genetic Variation Rat Island. Retake: Monday- last day!!!

Transcription

1 Agenda Warm-up: Look in your notebook for your grades Were you missing any of the assignments? Review Notes on Genetic Variation Rat Island Retake: Monday- last day!!!

2 Gene Pools 1.What makes a species? 2.What is a gene pool? 3.What is fitness? 4.How does diversity improve the chances of a species survival? 5.Why do organisms with poor traits decrease in number over time?

3 Date:

4 First thing s first Genetic variation is RANDOM and ensures that new generations have unique genotypes and phenotypes. This leads to evolution!

5 What influences genetic variability? 5 major things Genetic drift Gene flow Non-random mating Mutations Natural selection

6 What is it? Genetic Drift Random change in the frequency of alleles of a population over time Rare alleles will decrease in frequency and become eliminated Other alleles increase in frequency and become fixed Phenotypic changes may be more apparent in smaller populations than in larger ones

7 Gene Flow Movement of genes into or out of a population Occurs when individuals migrate or move between populations Immigration: organisms come into a population Emigration: organisms leave a population Receiving population increases in genetic variability

8 Non-Random Mating Organisms select who they want to mate with Limits the frequency of the expression of certain alleles

9 Mutations Changes in DNA Increase the frequencies and types of allele changes within the population

10 Survival of the fittest Natural Selection Allows for the best phenotypes to survive and be passed on to future generations

11 What if there is no change in alleles? Genetic equilibrium: no change in allele frequencies within a species Also called the Hardy-Weinberg principle

12 Hardy Weinberg Principle Five requirements: Very large population with no genetic drift. No movement into or out of the population. Random mating. No mutations in the gene pool. No natural selection.

13 Speciation Speciation: the process of forming a new species by biological evolution from a species that already exists New species usually form when organisms are isolated or separated so a new population is prevented from reproducing with the original population

14 Once isolation occurs, genetic variation and natural selection increase the differences between the separated populations As different traits are favored in the two populations (original and new) because of isolation, the gene pools gradually become so different that they are no longer able to reproduce Then they become 2 different species

15 Graded Notebooks. Vocabulary- needs to be completed and brought up to me BEFORE DUT on Thursday Please be working on your Study Guide (due Wednesday) I will be looking at NB the day of your test which is on and grading: Bird Beak Lab, Rat Island Activity, and 2 other assignments

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24 The rats need to had adaptations to help them to: get water evade predators get food deal with elements Directions: Draw a picture of your rat with all of its adaptations easily visible. Then, illustrate the conditions of your island. Picture must be colored and easy to understand.

25 Rat Facts: Rats are omnivores. This means they normally consume (eat) grass and plant seeds, the cambium layer under twigs and bark, small insects, and eggs. (They re known to eat nearly anything.) Rats need large amounts of fresh water (not salt water found in oceans). Produce 1-5 litters (groups of offspring) per year, each litter consisting of several offspring. This animal can swim, climb, and burrow.

26 ISLAND A Fairly flat Few hills Ground is soft dirt Several species of small bushes and shrubs grow in the center of that island No animal live on land; but the water is full of fish Surrounded by a coral reef which keeps the predators out Sandy beach with no algal growth Fresh water is available ISLAND C Desert like A few species of cactus live on the bare rocks A large cactus-eating tortoise lives on the island A species of very large bird nest on the island annually They build their nests on the rocks, and protect their eggs from the sun by standing over the nests with outspread wings The nests are always found on the windy side of the island which is somewhat cooled by offshore breezes. ISLAND B Rocky shoreline Many tide pools dot the island along the beach Wave action is somewhat sheltered by rock outcrops Tide pools contain barnacles, oysters, sea urchins and crabs Algae grows all around the island, however it is quite thin in the tide pools where the animals feed The current is quite strong along the rocky outcrops where the algae grows best Fresh water is available ISLAND D The island is an extinct volcano Plant life on the island changes with the altitude moving up the volcano Grasses grow at the base Further up the slope the grasses give way to low shrubs Half way up, the island becomes quite lush; Tropical plants and trees dominate the landscape At this altitude, the island experiences frequent rain showers There are two species of birds that live on the island: One is a raptor (meat eating) which preys upon the smaller birds. The other bird fishes the waters approximately one mile offshore. Both

27 Speciation Activity- Example adaptation speciation Isolation

28 Prime Time Retake Heredity DUT Opportunity 1: Take DUT today and turn in redo packet on Monday 2: Work on redo packet/study and take DUT Monday morning, Prime Time, or after school 3: Speak one-on-one with Mrs. Wright about another option Redo packet must be completed to count. Retakes will HELP your test grade. DO NOT PASS UP THIS OPPORTUNITY