10/7 Daily Catalyst

10/7 Daily Catalyst • 1. What is the best explanation for the fact that tuna, sharks, and dolphins all have a similar streamlined appearance? • 2. Which aspects of DNA are considered the strongest supporting evidence for the theory of evolution? • 3. What can you assume about analogous structures and their DNA?

10/7 Daily Catalyst Answers • 1. What is the best explanation for the fact that tuna, sharks, and dolphins all have a similar streamlined appearance? • This body shape helps them survive. • 2. Which aspects of DNA are considered the strongest supporting evidence for the theory of evolution? • There are DNA similarities in species with a common ancestor. • 3. What can you assume about analogous structures and their DNA? • Since they DO NOT have a common ancestor, they must not share DNA.

10/6 Class Business • Evolution Quiz #7 this Friday • Grades are due 10/11 for Mrs. Ireland • Class fees are due to me ASAP • Parent night is Thursday, Oct. 17th • Early release that day • Extra Credit for those who attend • Grade danger list: Robert, John, Lawrence, Kelsey, and Levonte

10/6 Class Business • Evolution Quiz #6: • Average: 2.16 • Top Scorers: Andrea and Sammara • Make-up: Abel and Tiana • Average: 2.91 • Top Scorers: Manahil, Tiffany, Ashley, Heba, Hector, Santos, Estephany, and Jordan • Make –up: Paige, Reem, and Talha (??)

10/6 Agenda • Daily Catalyst • Class Business • Objective • Microevolution • Reading • Debate debrief • Goals • Grade update (WE MUST DO THIS!!!)

What do you notice? Who are the organisms?

Humans Chimp Orangutan Dog

10/6 Daily Objective • We will be able to connect evolutionary changes in populations over time to a change in the environment.

Recap When gene frequencies occur, this is evolution occurring at the smallest scale. A change in the gene pool is called microevolution.

Genetic Variation • We have no problem picking out our friends and family in a crowd because of the variation in traits. • Not all variation is heritable. • Provide an example of this: • Muscle mass and tattoos

Key Point #1: • ONLY THE GENETIC COMPONENT OF VARIATION IS RELEVANT TO NATURAL SELECTION.

Darwin’s Observations • There is variation within a given species and the majority of this variation is inherited. This litter of kittens vary with respect to coat pattern and color. • Any variation may, to some degree, affect the ability of an organism to reproduce and contribute genes to the gene pool, thus affecting evolutionary success. • Species change over time. These changes are related to traits that are inherited or arise from an alteration of the genetic code. • Some inherited traits are beneficial and contribute to survival. • Whether a trait is beneficial or not is a function of the environment in which it lives.

Adaptations and Fitness • An adaptation is a genetically controlled trait that is favored by natural selection and gives the organism a reproductive advantage ensuring the trait is passed on to its descendants. • This trait may also allow the individual to survive longer thus increasing the reproductive rate of that individual.

Adaptations and Fitness • The antelope hare lives in the desert, and the snowshoe hare lives in the mountains. • Explain how the differences in their traits enhance their ability to survive in their respective environments. • Evolutionary success or fitness refers to the contribution of genes to the gene pool and NOT how long an organism lives.

The Effect of Environmental Change Earth’s environment is NOT STATIC, but rather ever changing. As a consequence, traits or adaptations that were favorable may become unfavorable. The peppered moth, Bistonbetularia is native to England and exists in two forms, one is dark and the other light with a “peppered” appearance. Birds are its main predator. Prior to the industrial revolution, only 2% of the moths were dark. The industrial revolution produced vast amounts of sulfur dioxide and soot from the burning of coal which altered the environment. Fifty years later 95% of the moths were dark. Propose an explanation!

Industrial Melanism England has since regulated the burning of coal and as a result, the trees are returning to their original state (A). Consequently, the coloring among the population of moths in Britain has shifted back so that the peppered moths are once again favored.

Evolution Defined • Evolution is defined as a change in the inherited characteristics of biological populations over successive generations. • Evolutionary processes give rise to diversity at every level of biological organization, from the molecular to the macroscopic. • As a result diversity is prevalent among molecules such as DNA as well as individual organisms and species of organisms.

Microevolution Microevolution is simply a change in gene frequency within a population. • Evolution at this scale can be observed over short periods of time such as from one generation to the next. • Example: The frequency of a gene for pesticide resistance in a population of crop pests increases. • Such a change might come about because • natural selection favored the gene • the population received new immigrants carrying the gene (gene flow) • nonresistant genes mutated into a resistant version of the gene • or random genetic drift from one generation to the next

Microevolution • A gene is a sequence of DNA nucleotides that specify a particular trait. • An allele is a different version of a geneFor example: black coat color or white coat color • Brepresents the allele for black coat color and b for white coat color. • Natural selection acts on individuals, but only populations evolve.

Remember last week when I told you your DNA determines your inward and outward appearance? • Genotype: genetic make up (gene for type O blood) • Phenotype: expression of traits (eye color) • Selection acts on phenotype because differential reproduction and survivorship depend on phenotype not genotype. Do you have what it takes to survive?

More Evolution Terms • Species-a group of interbreeding organisms that produce viable and fertile offspring in nature • Gene pool-total of all the genes in a given species • Allelic frequency-how often a allele appears

How does variation in a population or gene pool arise? Sources of Genetic Variation • MUTATIONS! • The wisteria pictured on the right has a mutation causing it to produce white flowers instead of purple flowers.

Types of Mutations • Only mutations occurring in gametes affect future generations. • Gamete cell, what?! • SEX CELLS (sperm and egg) • Obviously, mutations occurring in somatic cells do not affect future generations. • Somatic cells, what?! • All the rest of your cells (bones and skin) Mutations may cause a sheep to have a 5th leg. But this is not evolution!

Mutations can occur at either the gene or chromosomal level.

Point/Substition Mutations • One nucleotide is substituted for another. • If this mutation does not affect the function of the protein, then this mutaiton is harmless. • AKA silent mutations

Some mutations may add or delete nucleotides therefore affecting the protein that is coded for.

Frameshift Mutation • A frameshift mutation occurs as a result of either an insertion or deletion of a nucleotide. • AKA insertion mutation • AKA deletion mutation • This changes the amino acid sequence of the protein from that point forward. This has a huge effect!

What are my chances? • Mutation rates in eukaryotic cells average about one in every 100,000 genes per generation.

Effect of Sexual Reproduction Sexual reproduction recombines genes in new ways. This results in unique offspring that differ from either parent or sibling. Humans make 223 different kinds of gametes. Fertilization means that the uniqueness of an individual is 223 223. Or the probability that two siblings will be genetically identical (excluding identical twins) is 446. Sexual reproduction is like shuffling a deck of cards and every time getting a new and unique hand dealt. It is the major driving force of evolution.

Sexual Reproduction • Variation comes from unique combinations of alleles from the parents. • Just because your parents have a certain traits, does not mean you will get it. • Why?

10/8 Daily Catalyst • 1. Why cannot individuals evolve? • 2. Define and give an example of an allele. • 3. Why does natural selection only act on phenotype?

10/8 Daily Catalyst Answers • 1. Why cannot individuals evolve? • As an individual, we are already set with our DNA. We cannot change our DNA through out lifetime. • 2. Define and give an example of an allele. • A different version of a trait. • Example: Brown and blue eyes • 3. Why does natural selection only act on phenotype? • Your physical traits can give you the advantage to survive over another organism and the ability to reproduce and pass on these traits.

10/6 Class Business • Evolution Quiz #7 this Friday • Grades are due 10/11 for Mrs. Ireland • Class fees are due to me ASAP • Parent night is Thursday, Oct. 17th • Early release that day • Extra Credit for those who attend • Grade danger list: Robert, John, Lawrence, Kelsey, and Levonte • Limeades for learning

10/8 Agenda • Daily Catalyst • Class Business • Objective • Microevolution • Reading • Goal Setting • Grade update (we must do this)