Final Exam Biol 213 Starred

Per Capita Birth (b) and Death (d) Rates

Per capita birth rate b = B / N0; Per capita death rate d = D / N0

Per Capita Growth Rate (r)

Calculated as r = b - d; If r > 0 population grows, if r < 0 population shrinks, if r = 0 population is stable (b = d)

Predicting Population Growth (Exponential)

Next generation: N1 = N0 + r*N0 = N0(1 + r); Across t generations: Nt = N0(1 + r)^t

Real-Time Per Capita Growth Rate (rt) in Logistic Model

Calculated as rt = rmax * [(K - N) / K]; as N approaches K, rt approaches 0

Density-Dependent Regulation

Factors whose effects on per-individual birth and death rates intensify as population density increases

Biotic Causes of Density-Dependence

Intraspecific competition (for food/shelter/mates), predation cycles (e.g., lynx-hare), disease, parasites, and metabolic waste buildup

Density-Independent Regulation

Factors that alter birth and death rates regardless of population density

Abiotic Causes of Density-Independence

Temperature extremes (e.g., mountain pine beetle winter mortality), droughts, floods, and natural disasters

High Biotic Potential (r-Strategists)

Adapted to unstable environments; characterized by early maturity, large litters, high rmax, low competitive ability, and dramatic boom-and-bust cycles (e.g., lemmings)

Low Biotic Potential (K-Strategists)

Adapted to stable, crowded environments near carrying capacity; characterized by late maturity, small litters/single offspring, low rmax, and high competitive ability (e.g., elephants)

Gross Primary Productivity (GPP)

The total rate at which primary producers convert solar energy into chemical energy stored in organic compounds.

Net Primary Productivity (NPP)

The energy remaining and stored as biomass in primary producers after subtracting energy lost to producer respiration (Formula: NPP = GPP - Respiration).

Drivers of Primary Productivity

NPP increases with higher mean annual temperature, precipitation, sunlight intensity, and availability of limiting nutrients.

Ingestion vs. Egestion

Ingestion = total energy consumed by a heterotroph; Egestion = unabsorbed energy excreted as waste/feces.

Assimilation

The total energy absorbed into a consumer's body across the gut wall; Formula: Assimilation = Ingestion - Egestion.

Secondary Productivity (SP)

The net energy stored as new consumer biomass or reproduction; Formula: Secondary Productivity = Assimilation - Respiration.

Net Production Efficiency (NPE)

The proportion of assimilated energy converted into consumer biomass; Formula: NPE = (Secondary Productivity / Assimilation) * 100.

Ecological Efficiency (EE)

The proportion of primary producer energy (NPP) converted into consumer biomass at the next level; Formula: EE = (Secondary Productivity / NPP) * 100.

Batesian vs. Müllerian Mimicry

Batesian = a harmless, palatable species mimics a toxic/unpalatable species; Müllerian = two or more toxic/unpalatable species share a similar warning pattern.

Intrinsic vs. Instrumental Value of Biodiversity

Intrinsic Value = inherent worth of biodiversity independent of human benefit; Instrumental Value = functional value based on ecological goods and ecosystem services provided to humans

Genetic Drift

Unpredictable, random changes in allele frequencies across generations due to chance sampling of gametes; strongest in SMALL populations.

Effects of Genetic Drift

Loss of genetic variation (decreases heterozygosity, increases homozygosity), allele fixation or loss, and population divergence over time.

Gene Flow

The transfer of alleles into (immigration) or out of (emigration) a population.

Effects of Gene Flow

Homogenizes allele frequencies between populations (reduces divergence), restores genetic diversity lost to drift, but can slow down local adaptation.

Intersexual Selection

Mate choice where individuals of one sex (usually females) choose mates of the opposite sex based on specific traits/displays.

Intrasexual Selection

Direct competition between individuals of the same sex (usually male-male combat/territory defense) for mating access.

Phylogenetic Species Concept

Defines a species as the smallest group of individuals forming a distinct clade on a phylogenetic tree; Pros: objective/molecular, applies to sexual/asexual; Cons: expensive, genetic differences don't always equal biological differences.

Cladogram

A phylogenetic tree showing patterns of shared ancestry and lineage relationships without scaled branch lengths[cite: 11].

Phylogram

A phylogenetic tree where branch lengths are proportional to the amount of evolutionary change (e.g., genetic mutations)[cite: 11].

Chronogram

A phylogenetic tree where branch lengths represent absolute physical time elapsed along an explicit timescale[cite: 11].

Monophyletic Group (Clade)

A group consisting of a common ancestor and ALL of its descendants (passes the single "snip test")[cite: 11].

Paraphyletic Group

A group consisting of a common ancestor and SOME, but NOT ALL, of its descendants[cite: 11].

Polyphyletic Group

A group composed of taxa that excludes their most recent common ancestor[cite: 11].

Anagenesis vs. Cladogenesis

Anagenesis = evolutionary change within a single unbranched lineage over time; Cladogenesis = branching speciation where a parent species splits into distinct lineages[cite: 11].

Net Reproductive Rate (R_0) Formula

R_0 = \sum (l_x * m_x); represents the average total female offspring produced per female over her entire lifespan[

Product Rule of Probability

Used for independent events occurring simultaneously (Event A AND Event B): multiply their individual probabilities together.

Sum Rule of Probability

Used for mutually exclusive alternative outcomes (Event A OR Event B): add their individual probabilities together.

Polygenic Inheritance

An additive effect where two or more distinct genes collectively influence a single continuous phenotypic trait (e.g., skin color, height).

Pleiotropy

When a single gene mutation influences multiple, seemingly unrelated phenotypic traits (e.g., Sickle Cell Disease causing anemia, organ damage, and pain).

Genotype Frequency

The relative proportion of a specific genotype in a population; Formula: f(BB) = (Number of BB individuals) / (Total individuals).

Allele Frequency

The relative proportion of a specific allele at a genetic locus in a population; Formula: f(B) = (Number of B alleles) / (Total alleles in population).

Calculating Allele Frequencies from Genotype Frequencies

For a diploid population with two alleles: f(B) = f(BB) + 1/2 f(Bb) and f(b) = f(bb) + 1/2 f(Bb).

Five Assumptions of Hardy-Weinberg Equilibrium

1. No mutation; 2. No gene flow/migration; 3. Infinitely large population (no genetic drift); 4. No natural selection; 5. Random mating.

Hardy-Weinberg Equations

Allele frequencies: p + q = 1; Genotype frequencies: p² + 2pq + q² = 1 (where p = f(A), q = f(a), p² = f(AA), 2pq = f(Aa), q² = f(aa)).

Steps to Test if a Population is in HWE

1. Calculate observed genotype frequencies; 2. Calculate allele frequencies (p and q); 3. Calculate expected genotype frequencies (p², 2pq, q²); 4. Compare observed vs. expected.