Evolution Unit Study Guide

Study Notes

Evolution Unit Study Guide

Mutation: A change in DNA sequence. Example: A change in a gene that causes a different protein to be produced.
Variation: Differences in traits among individuals of a species. Example: Different heights among humans.
Heredity: Passing of traits from parents to offspring. Example: Eye color.
Darwin's Theory vs. Lamarck's Theory: Darwin's theory focuses on natural selection, where inherited traits advantageous to survival become more common. Lamarck's theory suggested that acquired traits could be inherited - this is false.
Antibiotic Resistance: Bacteria develop mutations that allow them to survive exposure to antibiotics.
Natural Selection: Organisms with traits better suited to their environment are more likely to survive and reproduce, passing on those beneficial traits.
Artificial Selection: Humans choose desired traits for breeding, leading to changes in species over time.
Acquired vs. Heritable Traits: Acquired traits are not passed to offspring. Heritable traits are passed from parents to offspring.
Sickle Cell Mutation: A mutation in the gene for hemoglobin, causing red blood cells to become sickle shaped. Pros: increased resistance to malaria. Cons: pain, anemia.
Homozygous Recessive Genotype for Sickle Cell Disease: SS (Homozygous recessive). This means the person carries two copies of the sickle cell gene in their genes.
Phenotype vs. Genotype: Genotype is the genetic makeup, while phenotype is the physical expression.
Homozygous vs. Heterozygous: Homozygous means two identical alleles, Heterozygous means two different alleles.
New Species Formation: An organism is considered a new species after: Reproductive isolation - where it can't interbreed with other organisms of the previous species; genetic differences; physical isolation; and adaptation.
Dolphin and Silver Fish: A population of dolphins eats silver fish, but if colorful fish become more common - and they are harder for the dolphins to see — the fish, who are seen more readily, would have an increased survival advantage when compared to the non-colorful fish.

Evolutionary Tree

Species with Longest Evolutionary History: The species shown at the very beginning of the evolutionary tree.
Species Most Closely Related to Perch: The species with the branch nearest to the Perch on the diagram.
Ancestral Species to Pigeon and Rat: The species at the branch from which the pigeon and the rat lineages both diverged.
Insect vs. Mammal Species Count: More insect species exist than mammal species.
Organism Ordering from Oldest to Youngest: Bacteria, fish, mammals.
Fossil Layer Significance: Fossils found in deeper layers are generally older than fossils found in upper layers.
Land Mammal to Whale Evolution: Evolution of anatomical adaptations like limbs evolving to fins, etc.
Sixth Extinction: A period of significant mass extinction of species.
Human Evolution Impact: Evolution and how humans can negatively or positively affect evolution today.
Bacterial Cellularity: Bacteria are unicellular (single-celled).
Dominant and Recessive Alleles for Hair Color: Dominant allele is H, recessive allele is h.
Punnett Square Percentage: Each box in the punnett square represents 25%
Probability of Long Hair Offspring: 75% chance the offspring will inherit long hair if one parent is homozygous dominant and one is heterozygous.
Probability of Homozygous Recessive Offspring: 25% chance the offspring will inherit two recessive alleles for short hair.