Study Guide for Test: Genetics and Natural Selection

8.5 Genetics

Multiple Choice Questions

1. Genotype Definition:
   • Genotype is the genetic makeup (e.g., Bb or TT)
2. Heterozygous Genotype Pair:
   • Tt
3. Dominant Allele Characteristics:
   • Always hides the recessive
4. Gregor Mendel:
   • The father of genetics
5. Purpose of a Punnett Square:
   • Helps find the genetic probabilities of traits

True or False Questions

1. DNA is found in the nucleus of a cell - True
2. A dominant trait only shows if two dominant alleles are present - False
3. You get half your DNA from each parent - True
4. A Punnett square shows possible gene combinations - True
5. A phenotype is the way something looks - True

Fill in the Blank

1. The gene versions you inherit from your parents are called alleles.
2. A recessive trait is hidden when a dominant allele is present.
3. The physical expression of your genes is called your phenotype.

Short Answer Questions

1. Importance of Two Copies of Each Gene:
   • Allows for genetic variation and can protect organisms if one gene copy has a mutation.
2. Consequences of Only Dominant Traits Passed On:
   • Lack of variation in traits could hurt survival if environments change.

Punnett Square Questions

1. Crossing Heterozygous Tall Plant (Tt) with Short Plant (tt):
   • Possible Genotypes: 2 Tt, 2 tt
   • Phenotypes: 50% Tall (Tt), 50% Short (tt)
2. Cross Two Heterozygous Brown-Eyed Parents (Bb):
   • Genotypes: 1 BB, 2 Bb, 1 bb
   • Phenotypes: 75% Brown Eyes (BB or Bb), 25% Blue Eyes (bb)

Long Essay Question

• Passing of Traits:
  • Traits are passed through genes with each parent contributing one allele per trait, forming the offspring's genotype. Dominant alleles will show in the phenotype. Example: Dominant brown eye allele (B) and recessive blue eye allele (b) results in brown eyes if B is present.

8.6 Natural Selection

Multiple Choice Questions

1. Natural Selection Definition:
   • Process where the best traits help organisms survive
2. Helpful Trait for Survival:
   • An adaptation
3. Example of an Adaptation:
   • A polar bear’s thick fur
4. Darwin’s Observation in the Galápagos Islands:
   • Different beaks on finches
5. Timeframe of Natural Selection:
   • Millions of years

True or False Questions

1. Natural selection is random and has no pattern - False
2. Organisms with helpful traits are more likely to survive and reproduce - True
3. Adaptations can be physical or behavioral - True
4. Evolution happens because of small changes over time - True
5. All organisms change to adapt instantly - False

Fill in the Blank

1. Animals that are better adapted to their environment survive longer.
2. Evolution is the change in a species over time.
3. A giraffe’s long neck is an example of an adaptation.

Short Answer Questions

1. Natural Selection and Changing Environments:
   • Traits that aid survival are more likely to be passed on.
2. Diverse Adaptations Among Animals:
   • Different environments require different traits for survival.

Medium Answer – Adaptation Question

• Alien Adaptation on Planet X:
  • Needs tough, heat-reflective skin and water storage like a camel; may be nocturnal to avoid daytime heat.

Long Essay Question

• How Natural Selection Works:
  • Variation, competition, survival, and reproduction contribute to evolution. Example: Darwin’s finches changed over generations as birds with strong beaks survived better on islands with hard seeds, leading to a population of mainly strong-beaked birds.