NATURAL SELECTION AND GENE FREQUENCY BY WOLFGANG RUBI CATALAN, MARNELLE MAC DULA, LIANNE UMALI, ERICA WILEY, & CHRIS YOUNG Student ID # ’s :
WHAT IS THAT? • • Natural selection is a key Gene frequency mechanism of evolution. demonstrates the • occurrence of an allele It is the process in which compared to other alleles of individuals with certain the same gene in a heritable traits survive and population. reproduce at higher rates than other individuals without those • The Hardy-Weinberg traits. Principle states allele • These traits allow them to frequencies will remain the adapt to various environmental same through generations in pressures, favoring their a population: with extremely survival and passing on of large in size, that randomly those suitable traits to
The Natural Selection The Hardy Weinberg Experiment Experiment Purpose: Purpose: To create a population and The natural selection lab aims to demonstrate how consistent Hardy- simulate the process by which Weinberg's principle really is. biological traits become more or less prevalent in a population that has a To observe the survival rates in changing environment. The natural genotypes and phenotypes of a selection lab will also attempt to show population over a span of 6 the relationship between predators generations. and prey. Hypothesis: Since there are mutations, certain Hypothesis: allele frequencies will decrease We predict that the predator will dramatically due to the naturally pick out the prey that is circumstances of the mutation most contrasting in color to its standards. For other cases of
SPECIMENS & MATERIALS The Natural Selection The Hardy Weinberg Experiment Experiment Specimens: Specimens: • • Red, white, and black beads 40 small colored paper which represented alleles. dots which represent the prey Materials: • • One clawed and double Red beads were used to clawed predators that kill Materials: represent red alleles. the species. • • 1 plastic cup for the “dead” Black beads were used to represent black alleles. dots • White beads were used to • 2 distinct fabric mats represent white alleles. which represented • 6 cups to place different allele different environments for combination in. your dots • 1 petri dish lid used to place allele • A computer to record
NATURAL SELECTION METHODS 1. Provided by the instructor, obtain one of the bottles of colored dots and gather 40 paper colored dots of one color per each individual in your group. 2. The instructor will then provide a fabric board that will serve as an “environment” for your species. 3. Place your colored species around the board in any order. Next, designate a predator for each group and send them to another environment where they will simulate the killing of a species by “eating them” for an allotted time set by the instructor. 4. After the event has occurred, calculate how many could survive, and add in the
NATURAL SELECTION RESULTS
NATURAL SELECTION ANALYSIS The different colored dots represented the genetic variation between species. We predicted that those species that stood out from their environment were less likely to survive. Those species that adapted to their environment over time had a better • Predators play a role in enforcing evolution and natural selection chance at survival. because they choose which populations survive and which do not. Those species newly introduced thrive because the predators are not yet familiar with them as shown in the previous slide the newly introduced dark green dots thrived more than any of the other populations. • When a population is brought into a new environment their survival may be affected. Those that once were able to successfully survive in the old environment may not be able to adjust so quickly to the new
HARDY WEINBERG METHODS Case 1-2 1. Gather all materials and count out 50 white beads and 50 red beads. 2. Put the red and white beads into a single cup so that the beads will mix. 3. Have 3 separate cups available for your RR, Rw, and ww bead combinations. 4. Have a member of the group randomly grab two beads at a time and put the appropriate bead combinations into its corresponding cup. 5. Once the team member has randomly picked all the beads, have someone count and record on your excel document how many of each combination was acquired. 6. Depending on which case you’re doing have a team member calculate the amount of white beads
GENE FREQUENCY RESULTS: Mutation Effects
GENE FREQUENCY RESULTS: Population Percent
GENE FREQUENCY ANALYSIS Our hypotheses were validated because the mutations affected allele frequencies significantly. The positive mutations led to an increase in population % whereas the negative mutations lead to a decrease in population %. Also, new species emerged with the introduction of the dominant black • In this population, the red allele is dominant while the white allele is allele producing favored phenotypes of recessive. The dominant phenotype of red is selected for, represented by the black and dark red. homozygous dominant RR and heterozygous dominant Rw. This favored trait is passed on to more offspring, increasing its allele frequency. • In both cases of 67% survival and 0% survival of the white allele, its frequency decreased dramatically over time. However, we see that it is almost impossible to eliminate the recessive alleles because of the heterozygous Rw genotype that codes for the favored phenotype. • Unsuccessful genotypes leads to unsuccessful phenotypes resulting in the decline of allele frequency over time. And natural selection consistently
HOW ARE THEY • Natural selection can increase the RELATED? frequencies of alleles if they are advantageous to a species survival and reproductive abilities. If they somehow produce a phenotype that is not a selective advantage, their frequency will decrease. • The change in allele frequencies is one way of defining evolution. A population evolves as “better” alleles increase in frequency in the gene pool. • This means that gene frequency and natural selection go hand in hand. They affect one another directly because the frequency of a gene makes it better suited for natural selection, while simultaneously, natural selection chooses which genes are going to be selected against.
WORKS CITED Campbell, Neil A., and Jane B. Reece. Campbell Biology. San Francisco, CA: Benjamin Cummings, 2011. Print. Darwin, Charles. "On The Origin of Species." The Origin of Species by Charles Darwin . Usenet Newsgroup, n.d. Web. 17 Feb. 2015. Photo Credits Darwin’s Finches: http://www1.northbrook28.net/~pamendelson/Mrs._Mendelsons_Site/Natural_Selection_Classification_files/shapeimage_3.png Colorful Chromosomes: http://genetics.thetech.org/sites/default/files/KaryColor.gif Natural Selection Banner : http://i.ytimg.com/vi/aTftyFboC_M/maxresdefault.jpg Hardy Weinberg Penguins: http://i.ytimg.com/vi/oG7ob-MtO8c/maxresdefault.jpg NS Cartoon Fish: http://media-cache-ak0.pinimg.com/736x/1d/d1/34/1dd13452486e4fd130930d50d2acbb53.jpg Gene Frequency Goats: http://farm7.staticflickr.com/6128/5916685986_f891ba6255.jpg Natural Selection Birds and Beetles: http://uedata.berkeley.edu//media/3/52571_evo_resources_resource_image_380_original.gif All other photography were done by SCC Biology 3 Students
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