Biology Flashcards: Explain Biodiversity And Population Dynamics

What this deck covers

This deck focuses on Explain Biodiversity And Population Dynamics, giving you a quick way to review the definitions, rules, and examples that matter most for Biology.

How to use these flashcards

Work through these flashcards in short sessions. Try to answer each prompt before flipping the card, then revisit any cards you miss until the explanation feels automatic.

Flashcard 1: Identify whether regulation is density-dependent: disease spreads faster as population density rises.

Answer: Density-dependent. Higher density increases contact rates and transmission.

Flashcard 2: What is functional diversity in an ecosystem?

Answer: The diversity of ecological roles and traits that affect ecosystem processes. Different functional roles contribute to ecosystem processes.

Flashcard 3: What is primary productivity and how can biodiversity influence it?

Answer: Rate of biomass production; higher diversity can increase productivity. Diverse plant communities often show greater total biomass production.

Flashcard 4: What is competitive exclusion in population ecology?

Answer: Two species with identical niches cannot stably coexist. Complete niche overlap leads to competitive displacement.

Flashcard 5: What is genetic drift and when is it strongest in population dynamics?

Answer: Random allele frequency change; strongest in small populations. Sampling effects dominate when few individuals reproduce.

Flashcard 6: What is the "insurance effect" of biodiversity on population dynamics?

Answer: Multiple species can maintain function when one species declines. Functional redundancy maintains ecosystem services when species decline.

Flashcard 7: What is inbreeding depression and what population condition increases it?

Answer: Reduced fitness from inbreeding; more likely in small, isolated populations. Related mating increases homozygosity and harmful recessive expression.

Flashcard 8: What is the minimum viable population (MVP) concept?

Answer: The smallest population size likely to persist long term. Critical threshold for avoiding demographic and genetic risks.

Flashcard 9: What is gene flow and how does it affect genetic diversity?

Answer: Movement of alleles between populations; it typically increases diversity. Migrants introduce new alleles and counteract drift effects.

Flashcard 10: What is the typical effect of higher biodiversity on ecosystem stability?

Answer: Higher biodiversity generally increases stability and resilience. Diverse communities buffer against environmental fluctuations.

Flashcard 11: What is bottom-up control in population dynamics?

Answer: Resource availability (producers/nutrients) limits higher trophic populations. Energy and nutrients flow up from primary producers.

Flashcard 12: State the per capita growth rate definition using $r$ in population ecology.

Answer: $r$ is the per-individual rate of increase (births minus deaths per capita). Birth and death rates determine net population change.

Flashcard 13: Which option best predicts stability: A low evenness, B high evenness, assuming equal richness?

Answer: B high evenness. Balanced abundances create more stable community dynamics.

Flashcard 14: Identify whether regulation is density-independent: a hurricane reduces all populations in a region.

Answer: Density-independent. External forces affect populations regardless of their size.

Flashcard 15: Identify the expected trend: as species richness increases, what happens to food web redundancy?

Answer: Food web redundancy generally increases. More pathways provide backup when individual species fail.

Flashcard 16: Identify the most likely result of a population bottleneck on future adaptability.

Answer: Reduced adaptability due to lower genetic variation. Fewer alleles limit evolutionary responses to future challenges.

Flashcard 17: What is a trophic cascade?

Answer: A chain of effects across trophic levels after a population change. Predator changes ripple through multiple feeding levels.

Flashcard 18: Identify the expected trend: as species richness increases, what happens to food web redundancy?

Answer: Food web redundancy generally increases. More pathways provide backup when individual species fail.

Flashcard 19: Identify the relationship between biodiversity and ecosystem resilience after disturbance.

Answer: Higher biodiversity usually increases the speed and likelihood of recovery. More species provide alternative pathways for ecosystem recovery.

Flashcard 20: What is an extinction vortex in small populations?

Answer: A reinforcing cycle of small $N$, low diversity, and rising extinction risk. Multiple factors compound to accelerate population decline.

Flashcard 21: What is habitat fragmentation and its typical effect on biodiversity?

Answer: Breaking habitat into patches; it often reduces biodiversity and gene flow. Isolated patches lose connectivity and species diversity.

Flashcard 22: What is the typical effect of predator removal on prey population size?

Answer: Prey population size often increases, potentially reducing plant biomass. Released from predation pressure, prey populations expand.

Flashcard 23: Identify the expected trend: as habitat fragmentation increases, what happens to gene flow?

Answer: Gene flow usually decreases. Barriers reduce movement and genetic exchange between populations.

Flashcard 24: Identify the relationship between biodiversity and ecosystem resilience after disturbance.

Answer: Higher biodiversity usually increases the speed and likelihood of recovery. More species provide alternative pathways for ecosystem recovery.

Flashcard 25: What is population density in ecology?

Answer: Number of individuals per unit area or volume. Measures crowding intensity in a given space.

Flashcard 26: What is species richness in a community?

Answer: The number of different species present. Counts distinct species without considering their relative abundances.

Flashcard 27: What is functional diversity in an ecosystem?

Answer: The diversity of ecological roles and traits that affect ecosystem processes. Different functional roles contribute to ecosystem processes.

Flashcard 28: What is logistic growth in population dynamics?

Answer: Growth slows as $N$ approaches $K$; an S-shaped curve. Environmental resistance slows growth near carrying capacity.

Flashcard 29: What is biodiversity, as used in ecology when comparing communities?

Answer: The variety of life across genes, species, and ecosystems in an area. Encompasses genetic, species, and ecosystem variety in a defined region.

Flashcard 30: What is density-independent regulation of population size?

Answer: Population limits act regardless of density (e.g., drought, storms). Environmental factors affect all individuals equally.

Flashcard 31: What is the "insurance effect" of biodiversity on population dynamics?

Answer: Multiple species can maintain function when one species declines. Functional redundancy maintains ecosystem services when species decline.

Flashcard 32: What is a population bottleneck and its effect on genetic diversity?

Answer: A sharp $N$ reduction that decreases genetic variation. Surviving individuals carry only a subset of original alleles.

Flashcard 33: What is an invasive species in terms of biodiversity and populations?

Answer: A nonnative species that spreads and disrupts native populations and diversity. Outcompetes natives and alters community structure.

Flashcard 34: What is density-dependent regulation of population size?

Answer: Population limits intensify as density increases (e.g., competition, disease). Higher crowding amplifies competition and resource depletion.

Flashcard 35: What is a limiting resource in population dynamics?

Answer: A resource that restricts population growth when scarce. Essential resources like food or space become bottlenecks.

Flashcard 36: What is ecological succession and how does biodiversity typically change over time?

Answer: Community change after disturbance; biodiversity often increases then stabilizes. Species accumulate during recovery from early to late stages.

Flashcard 37: What is carrying capacity ($K$) of an environment?

Answer: The maximum population size the environment can sustainably support. Environmental capacity determines long-term population stability.

Flashcard 38: What is functional redundancy and how does it affect population stability?

Answer: Multiple species share roles; it buffers ecosystem function against declines. Backup species maintain function when others decline.

Flashcard 39: What is biodiversity, as used in ecology when comparing communities?

Answer: The variety of life across genes, species, and ecosystems in an area. Encompasses genetic, species, and ecosystem variety in a defined region.

Flashcard 40: What is inbreeding depression and what population condition increases it?

Answer: Reduced fitness from inbreeding; more likely in small, isolated populations. Related mating increases homozygosity and harmful recessive expression.

Flashcard 41: What is edge effect and how can it influence population dynamics in fragments?

Answer: Edge conditions alter survival and reproduction near habitat boundaries. Boundary zones create different microclimates and species interactions.

Flashcard 42: State the per capita growth rate definition using $r$ in population ecology.

Answer: $r$ is the per-individual rate of increase (births minus deaths per capita). Birth and death rates determine net population change.

Flashcard 43: What is top-down control in population dynamics?

Answer: Predators regulate prey populations and can shape community composition. Predation pressure constrains lower trophic level abundance.

Flashcard 44: Identify the most likely result of a population bottleneck on future adaptability.

Answer: Reduced adaptability due to lower genetic variation. Fewer alleles limit evolutionary responses to future challenges.

Flashcard 45: Identify whether regulation is density-dependent: disease spreads faster as population density rises.

Answer: Density-dependent. Higher density increases contact rates and transmission.

Flashcard 46: What is competitive exclusion in population ecology?

Answer: Two species with identical niches cannot stably coexist. Complete niche overlap leads to competitive displacement.

Flashcard 47: What is carrying capacity ($K$) of an environment?

Answer: The maximum population size the environment can sustainably support. Environmental capacity determines long-term population stability.

Flashcard 48: What is a disturbance and how can it affect biodiversity and populations?

Answer: A disruptive event that changes resources; it can reset succession and $N$. Opens niches and creates opportunities for colonization.

Flashcard 49: Identify the relationship between biodiversity loss and food web complexity.

Answer: Biodiversity loss typically simplifies food webs and reduces redundancy. Fewer species create simpler, less stable food networks.

Flashcard 50: What is r-selected life history strategy in population dynamics?

Answer: High reproduction, early maturity, low parental care; rapid growth. Maximizes reproductive output in unpredictable environments.

Flashcard 51: What is logistic growth in population dynamics?

Answer: Growth slows as $N$ approaches $K$; an S-shaped curve. Environmental resistance slows growth near carrying capacity.

Flashcard 52: What is primary productivity and how can biodiversity influence it?

Answer: Rate of biomass production; higher diversity can increase productivity. Diverse plant communities often show greater total biomass production.

Flashcard 53: What is the direct relationship between biodiversity and disease spread risk?

Answer: Lower biodiversity can increase disease transmission in some systems. Fewer hosts can concentrate disease transmission pathways.

Flashcard 54: What is exponential growth in population dynamics?

Answer: Growth proportional to $N$; a J-shaped increase when resources are abundant. Unlimited resources allow maximum reproductive potential.

Flashcard 55: Identify the relationship: if biodiversity increases, what usually happens to variation in total ecosystem biomass over time?

Answer: Variation usually decreases (biomass becomes more stable). Portfolio effects from multiple species reduce temporal variability.

Flashcard 56: What is an extinction vortex in small populations?

Answer: A reinforcing cycle of small $N$, low diversity, and rising extinction risk. Multiple factors compound to accelerate population decline.

Flashcard 57: What is the typical effect of predator removal on prey population size?

Answer: Prey population size often increases, potentially reducing plant biomass. Released from predation pressure, prey populations expand.

Flashcard 58: Identify the expected trend: as habitat fragmentation increases, what happens to gene flow?

Answer: Gene flow usually decreases. Barriers reduce movement and genetic exchange between populations.

Flashcard 59: Identify the relationship: if biodiversity increases, what usually happens to variation in total ecosystem biomass over time?

Answer: Variation usually decreases (biomass becomes more stable). Portfolio effects from multiple species reduce temporal variability.

Flashcard 60: Choose the correct outcome: if a keystone predator is removed, what happens to prey diversity?

Answer: Prey diversity often decreases due to competitive dominance by one prey species. One superior competitor excludes others without predation pressure.

Flashcard 61: What is the dilution effect hypothesis for infectious disease?

Answer: Higher host diversity can reduce transmission by diluting competent hosts. Non-competent hosts interrupt transmission chains to susceptible species.

Flashcard 62: What is gene flow and how does it affect genetic diversity?

Answer: Movement of alleles between populations; it typically increases diversity. Migrants introduce new alleles and counteract drift effects.

Flashcard 63: What is density-independent regulation of population size?

Answer: Population limits act regardless of density (e.g., drought, storms). Environmental factors affect all individuals equally.

Flashcard 64: What is functional redundancy and how does it affect population stability?

Answer: Multiple species share roles; it buffers ecosystem function against declines. Backup species maintain function when others decline.

Flashcard 65: What is the rescue effect in metapopulation dynamics?

Answer: Immigration reduces local extinction risk in small populations. Migrants prevent local populations from declining to extinction.

Flashcard 66: What is the typical effect of higher biodiversity on ecosystem stability?

Answer: Higher biodiversity generally increases stability and resilience. Diverse communities buffer against environmental fluctuations.

Flashcard 67: What is habitat fragmentation and its typical effect on biodiversity?

Answer: Breaking habitat into patches; it often reduces biodiversity and gene flow. Isolated patches lose connectivity and species diversity.

Flashcard 68: What is edge effect and how can it influence population dynamics in fragments?

Answer: Edge conditions alter survival and reproduction near habitat boundaries. Boundary zones create different microclimates and species interactions.

Flashcard 69: What is a disturbance and how can it affect biodiversity and populations?

Answer: A disruptive event that changes resources; it can reset succession and $N$. Opens niches and creates opportunities for colonization.

Flashcard 70: What is species richness in a community?

Answer: The number of different species present. Counts distinct species without considering their relative abundances.

Flashcard 71: What is K-selected life history strategy in population dynamics?

Answer: Lower reproduction, later maturity, higher parental care; stable near $K$. Emphasizes survival and competitive ability in stable environments.

Flashcard 72: Choose the correct link: if pollinator diversity declines, what happens to plant reproduction rates?

Answer: Plant reproduction rates often decrease. Pollinator loss directly reduces plant reproductive success.

Flashcard 73: What is the rescue effect in metapopulation dynamics?

Answer: Immigration reduces local extinction risk in small populations. Migrants prevent local populations from declining to extinction.

Flashcard 74: What is K-selected life history strategy in population dynamics?

Answer: Lower reproduction, later maturity, higher parental care; stable near $K$. Emphasizes survival and competitive ability in stable environments.

Flashcard 75: What is niche partitioning and how does it relate to biodiversity?

Answer: Species use different resources; it reduces competition and supports diversity. Resource specialization allows coexistence and maintains diversity.

Flashcard 76: What is genetic drift and when is it strongest in population dynamics?

Answer: Random allele frequency change; strongest in small populations. Sampling effects dominate when few individuals reproduce.

Flashcard 77: What is r-selected life history strategy in population dynamics?

Answer: High reproduction, early maturity, low parental care; rapid growth. Maximizes reproductive output in unpredictable environments.

Flashcard 78: What is the diversity–stability hypothesis in one sentence?

Answer: More diverse ecosystems tend to show more stable functioning over time. More species provide functional backup during disturbances.

Flashcard 79: What is the direct relationship between biodiversity and disease spread risk?

Answer: Lower biodiversity can increase disease transmission in some systems. Fewer hosts can concentrate disease transmission pathways.

Flashcard 80: What is the dilution effect hypothesis for infectious disease?

Answer: Higher host diversity can reduce transmission by diluting competent hosts. Non-competent hosts interrupt transmission chains to susceptible species.

Flashcard 81: Choose the correct outcome: if a keystone predator is removed, what happens to prey diversity?

Answer: Prey diversity often decreases due to competitive dominance by one prey species. One superior competitor excludes others without predation pressure.

Flashcard 82: What is an invasive species in terms of biodiversity and populations?

Answer: A nonnative species that spreads and disrupts native populations and diversity. Outcompetes natives and alters community structure.

Flashcard 83: Identify whether regulation is density-independent: a hurricane reduces all populations in a region.

Answer: Density-independent. External forces affect populations regardless of their size.

Flashcard 84: What is species evenness in a community?

Answer: How evenly individuals are distributed among species. Measures whether species abundances are balanced or skewed.

Flashcard 85: What is ecological succession and how does biodiversity typically change over time?

Answer: Community change after disturbance; biodiversity often increases then stabilizes. Species accumulate during recovery from early to late stages.

Flashcard 86: What is species evenness in a community?

Answer: How evenly individuals are distributed among species. Measures whether species abundances are balanced or skewed.

Flashcard 87: Which option best predicts stability: A low evenness, B high evenness, assuming equal richness?

Answer: B high evenness. Balanced abundances create more stable community dynamics.

Flashcard 88: What is the founder effect and how can it change biodiversity within a population?

Answer: A new population starts from few individuals, altering allele frequencies. Random sampling of alleles creates genetic differences from source.

Flashcard 89: What is a population bottleneck and its effect on genetic diversity?

Answer: A sharp $N$ reduction that decreases genetic variation. Surviving individuals carry only a subset of original alleles.

Flashcard 90: What is top-down control in population dynamics?

Answer: Predators regulate prey populations and can shape community composition. Predation pressure constrains lower trophic level abundance.

Flashcard 91: What is a keystone species?

Answer: A species with a disproportionately large effect on its ecosystem. Their ecological role exceeds their numerical abundance.

Flashcard 92: What is niche partitioning and how does it relate to biodiversity?

Answer: Species use different resources; it reduces competition and supports diversity. Resource specialization allows coexistence and maintains diversity.

Flashcard 93: What is population size ($N$) in population dynamics?

Answer: The total number of individuals in a population. Fundamental measure for tracking population changes over time.

Flashcard 94: What is a metapopulation in population ecology?

Answer: A set of subpopulations linked by dispersal among habitat patches. Interconnected patches allow recolonization after local extinctions.

Flashcard 95: What is a metapopulation in population ecology?

Answer: A set of subpopulations linked by dispersal among habitat patches. Interconnected patches allow recolonization after local extinctions.

Flashcard 96: Choose the correct link: if pollinator diversity declines, what happens to plant reproduction rates?

Answer: Plant reproduction rates often decrease. Pollinator loss directly reduces plant reproductive success.

Flashcard 97: What is the founder effect and how can it change biodiversity within a population?

Answer: A new population starts from few individuals, altering allele frequencies. Random sampling of alleles creates genetic differences from source.

Flashcard 98: Identify the relationship between biodiversity loss and food web complexity.

Answer: Biodiversity loss typically simplifies food webs and reduces redundancy. Fewer species create simpler, less stable food networks.

Flashcard 99: What is a limiting resource in population dynamics?

Answer: A resource that restricts population growth when scarce. Essential resources like food or space become bottlenecks.

Flashcard 100: What is population size ($N$) in population dynamics?

Answer: The total number of individuals in a population. Fundamental measure for tracking population changes over time.