Question

traits,survival and reproducytion quick check

Answer 1

Here’s a short, focused “quick check” on traits, survival, and reproduction — definitions, key points, then 12 quick questions with answers and one-line explanations.

Key terms (one-line):
- Trait: any observable characteristic of an organism (morphology, behavior, physiology).
- Genotype vs phenotype: genotype = genetic makeup; phenotype = expressed trait.
- Heritable trait: encoded in DNA and can be passed to offspring.
- Adaptation: a trait that increases an organism’s survival or reproductive success in a particular environment.
- Fitness: relative reproductive success (how many viable offspring an organism leaves).
- Natural selection: differential survival/reproduction of individuals with different traits.
- Variation source: mutation, recombination, gene flow; drift/random sampling also changes frequencies.
- Sexual vs asexual reproduction: sexual increases genetic variation; asexual produces clones (less variation).

Quick check questions (answer below each):

1) Define “trait” and “adaptation.”
- Answer: Trait = any characteristic of an organism. Adaptation = trait that increases survival/reproductive success in a specific environment.

2) True or False: Acquired traits (e.g., muscle built in life) are usually inherited by offspring.
- Answer: False. Most acquired traits are not encoded in germ-line DNA and are not inherited.

3) How does natural selection change trait frequencies in a population?
- Answer: Traits that increase fitness become more common because individuals with them leave more offspring.

4) Which processes introduce new genetic variation? (pick all that apply): mutation, gene flow, natural selection, genetic drift
- Answer: mutation and gene flow introduce new variation. Selection and drift change frequencies of existing variation.

5) What does “fitness” measure?
- Answer: Fitness measures reproductive success (number of surviving offspring, often relative to others).

6) The classic peppered moth example shows which type of selection (stabilizing, directional, disruptive)?
- Answer: Directional selection — frequency shifted toward dark morphs when environment darkened.

7) How does sexual reproduction affect genetic variation compared to asexual reproduction?
- Answer: Sexual reproduction increases variation (recombination, independent assortment); asexual produces genetically similar offspring.

8) Bottleneck and founder effects are examples of which evolutionary force?
- Answer: Genetic drift (random change in allele frequencies due to small population size).

9) What is a selective pressure? Give one example.
- Answer: Any environmental factor that affects survival/reproduction (e.g., predators, temperature, antibiotics).

10) If a population faces a colder climate, which trait change is likely to be selected for?
- Answer: Traits that improve cold survival (e.g., thicker fur, greater fat stores) will increase in frequency if heritable.

11) Quick allele-frequency calculation: 100 individuals, 40 carry allele A (one copy each assumed)—what’s allele frequency of A?
- Answer: 0.40 (40/100 = 0.4). Note: if diploid counts matter, clarify number of alleles per individual.

12) Why does antibiotic resistance often evolve quickly in bacteria?
- Answer: High reproduction rates, strong selective pressure from antibiotics, mutations and horizontal gene transfer supply resistance variants that spread.

Want this as a short quiz (no answers) you can use with students, or a deeper explanation/example for any question?