BI 108 Test 1 Study Flashcards

Comprehensive practice flashcards covering anatomy of a scientific paper, DNA and inheritance, population genetics, Hardy-Weinberg equilibrium, natural selection, and genetic drift.

What general structural progression does a scientific paper follow from beginning to end?

A scientific paper generally moves from Broad $\rightarrow$ Specific $\rightarrow$ Broad.

What four main components are typically included in the abstract of a scientific paper?

The abstract usually includes the research question, general methods, major results, and main conclusion.

What is the key difference between a hypothesis and a prediction in deductive research?

A hypothesis is a proposed explanation that can be tested, whereas a prediction is a specific expected result that should occur if the hypothesis is correct.

What is the correct sequence of steps in deductive research?

$$\text{Hypothesis} \rightarrow \text{Prediction} \rightarrow \text{Test} \rightarrow \text{Results}$$

On a scientific figure, what do the x-axis and y-axis usually represent?

The x-axis represents the variable being compared or manipulated, and the y-axis represents the variable being measured.

What formula illustrates the relationship between genotype, environment, and phenotype?

$$\text{Genotype} + \text{Environment} \rightarrow \text{Phenotype}$$

What processes define transcription and translation in the central pathway of biological information flow?

Transcription is copying information from DNA into RNA ($\text{DNA} \rightarrow \text{RNA}$), and translation is using RNA information to produce a protein ($\text{RNA} \rightarrow \text{Protein}$).

How many total chromosomes and pairs of chromosomes do human cells contain?

Humans have $23$ pairs, which equals $46$ total chromosomes.

How do homologous chromosomes differ from sister chromatids?

Homologous chromosomes are pairs inherited one from each parent that contain the same genes but may have different alleles. Sister chromatids are replicated copies of the same chromosome that are generally identical in DNA sequence before crossing over.

How do mitosis and meiosis differ in terms of daughter cell count, genetic similarity, and ploidy changes?

Mitosis produces $2$ genetically similar cells and maintains chromosome number ($2n \rightarrow 2n + 2n$). Meiosis produces $4$ haploid cells, generates genetic variation, and reduces chromosome number ($2n \rightarrow n + n + n + n$).

What is the distinction between anisogamy and isogamy?

Anisogamy is reproduction involving gametes that differ in size or form, whereas isogamy involves gametes that are similar in size or form.

What are the five mechanisms that generate genetic variation?

The five mechanisms are: 1. Mutation, 2. Chromosome segregation, 3. Crossing over, 4. Independent assortment, and 5. Random fertilization.

When is a mutation considered heritable?

A mutation is heritable when it occurs in genetic material that contributes to offspring.

What is Mendel's Law of Segregation?

The Law of Segregation states that the two alleles for a gene separate during gamete formation, so each gamete receives one allele (e.g., $Aa \rightarrow A$ or $a$).

What is Mendel's Law of Independent Assortment?

The Law of Independent Assortment states that alleles of different genes can be distributed into gametes independently during meiosis when the genes are not linked.

When and where does crossing over occur during meiosis?

Crossing over occurs during Prophase I of meiosis between homologous chromosomes.

What is biological evolution and at what biological level does it occur?

Biological evolution is a change in the genetic composition of a population across generations. It occurs to populations, not individual organisms.

What is ontogeny and why is it not classified as biological evolution?

Ontogeny refers to changes that occur during the lifetime of an individual as it develops. It is not evolution because evolution requires genetic change in a population across generations.

What is phenotypic plasticity and why is it not classified as biological evolution?

Phenotypic plasticity is the ability of one genotype to produce different phenotypes in response to environmental conditions. It is not evolution because environmental changes to an individual's phenotype do not alter allele frequencies in the population across generations.

What are the three primary evolutionary processes emphasized in population genetics?

The three evolutionary processes are selection, genetic drift, and gene flow.

What are the two Hardy-Weinberg equilibrium equations for allele and genotype frequencies?

Allele frequencies: $p + q = 1$; Genotype frequencies: $p^2 + 2pq + q^2 = 1$.

What are the five conditions required for a population to remain in Hardy-Weinberg equilibrium?

1. No mutation, 2. Random mating, 3. No natural selection, 4. Very large population, 5. No gene flow.

Does rejecting Hardy-Weinberg equilibrium automatically prove that natural selection is occurring?

No. Rejecting Hardy-Weinberg equilibrium only means at least one assumption of the null model has been violated (mutation, selection, genetic drift, gene flow, or non-random mating). Additional evidence is needed to prove which process caused the deviation.

What are the four necessary and sufficient conditions for natural selection to cause evolutionary change?

1. Variation, 2. Heritability, 3. Differential Fitness, and 4. Non-Random Relationship Between Trait and Fitness.

How is evolutionary fitness defined?

Fitness is defined as relative reproductive success, referring to how much an individual contributes viable offspring to the next generation.

How are genetic versus environmental effects distinguished in a reciprocal transplant experiment?

If individuals from different populations remain different in the same environment, genetic differences contribute. If individuals become more similar in the same environment, environmental differences contribute.

What prediction defines reciprocal home-site advantage in local adaptation?

Each population displays higher fitness in its own native environment than the non-native population does.

Why is natural selection considered deterministic while genetic drift is stochastic?

Natural selection is deterministic because trait differences systematically affect reproductive success; genetic drift is stochastic because changes in allele frequencies are caused purely by chance.

Why does genetic drift exert a stronger effect in small populations than in large ones?

Because a random event affects a much larger proportion of individuals and alleles in a small population compared to a large population.

What does allele fixation mean in population genetics?

Fixation occurs when an allele reaches a frequency of $100\%$ in a population, meaning all alternative alleles have disappeared.

How do the founder effect and bottleneck effect differ?

Founder effect occurs when a small group leaves an original population to establish a new population. Bottleneck effect occurs when a disaster or event drastically reduces an existing population.

What conceptual connection does the Donihue et al. (2018) study illustrate?

Environmental event $\rightarrow$ differential survival $\rightarrow$ possible natural selection $\rightarrow$ phenotypic change.