NATURAL SELECTION AND GENE FREQUENCY BY WOLFGANG RUBI CATALAN, - - PowerPoint PPT Presentation

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

mechanism of evolution.

• It is the process in which

individuals with certain heritable traits survive and reproduce at higher rates than

• ther individuals without those

traits.

• These traits allow them to

adapt to various environmental pressures, favoring their survival and passing on of those suitable traits to

• Gene frequency

demonstrates the

• ccurrence of an allele

compared to other alleles of the same gene in a population.

• The Hardy-Weinberg

Principle states allele frequencies will remain the same through generations in a population: with extremely large in size, that randomly

Purpose: The natural selection lab aims to simulate the process by which biological traits become more or less prevalent in a population that has a changing environment. The natural selection lab will also attempt to show the relationship between predators and prey. Hypothesis: We predict that the predator will naturally pick out the prey that is most contrasting in color to its

The Natural Selection Experiment The Hardy Weinberg Experiment

Purpose: To create a population and demonstrate how consistent Hardy- Weinberg's principle really is. To observe the survival rates in genotypes and phenotypes of a population over a span of 6 generations. Hypothesis: Since there are mutations, certain allele frequencies will decrease dramatically due to the circumstances of the mutation

• standards. For other cases of

Specimens:

• 40 small colored paper

dots which represent the prey

• One clawed and double

clawed predators that kill the species. Specimens:

• Red, white, and black beads

which represented alleles. Materials:

• Red beads were used to

represent red alleles.

• Black beads were used to

represent black alleles.

• White beads were used to

represent white alleles.

• 6 cups to place different allele

combination in.

• 1 petri dish lid used to place allele

The Natural Selection Experiment The Hardy Weinberg Experiment

Materials:

• 1 plastic cup for the “dead”

dots

• 2 distinct fabric mats

which represented different environments for your dots

• A computer to record

SPECIMENS & MATERIALS

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

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 chance at survival.

• Predators play a role in enforcing evolution and natural selection

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

NATURAL SELECTION ANALYSIS

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

HARDY WEINBERG METHODS

GENE FREQUENCY RESULTS: Mutation Effects

GENE FREQUENCY RESULTS: Population Percent

• In this population, the red allele is dominant while the white allele is
• recessive. The dominant phenotype of red is selected for, represented by the

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

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 allele producing favored phenotypes of black and dark red.

• Natural selection can increase the

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
• f 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.

HOW ARE THEY RELATED?

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.

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

WORKS CITED

Photo Credits