Revised Final Exam Biol 213

Population Size Drivers

Population size increases via births (B) and immigration; it decreases via deaths (D) and emigration

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

Intrinsic Rate of Increase (rmax)

The maximum possible per capita growth rate for a species under ideal, unlimited environmental conditions

Body Size vs. Intrinsic Growth Rate (rmax)

Smaller organisms (e.g., bacteria) have high rmax values; larger organisms (e.g., elephants, humans) have low rmax values and longer generation times

Exponential Growth Model

Predicts unlimited population expansion (J-shaped curve); assumes ideal conditions with no theoretical upper limit or carrying capacity

Carrying Capacity (K)

The maximum population size that a specific environment can sustainably support over time, where birth rate equals death rate (b = d)

Logistic Growth Model

Predicts population growth with density dependence (S-shaped curve); growth rate slows as population size (N) approaches carrying capacity (K)

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

Biotic Potential

The maximum reproductive capacity of a population under ideal conditions (equal to rmax)

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)

Over-Shooting Carrying Capacity (K)

When a rapid population boom drastically exceeds K, severe resource depletion occurs, resulting in a dramatic population crash or total die-off (e.g., St. Matthew Island reindeer)

Ecosystem Components

Ecosystems consist of biotic components (living organisms) interacting with abiotic components (non-living physical/chemical elements like sunlight, temperature, water, nutrients).

Autotrophs

Organisms that synthesize organic compounds by converting ambient physical/chemical energy into biologically usable energy (e.g., photoautotrophs using sunlight).

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.

Primary Limiting Nutrients

Nitrogen (N) and Phosphorus (P) are the two most common limiting nutrients for primary producers.

Trophic Levels

1 = Primary Producers; 2 = Primary Consumers (herbivores); 3 = Secondary Consumers (carnivores); 4 = Tertiary Consumers; 5 = Apex Predators.

Trophic Energy Transfer (~10% Rule)

Only about 10% of energy is transferred from one trophic level to the next; ~90% is lost through metabolic heat, respiration, and unconsumed biomass.

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.

Bottom-Up Trophic Control

Ecosystem regulation where the availability of primary producers and nutrients determines the biomass and structure of higher trophic levels.

Top-Down Trophic Control

Ecosystem regulation where apex predators control herbivore abundance, indirectly altering primary producer biomass (trophic cascade).

Ecological Community

A group of populations of different species living and interacting in the same location at the same time.

Classification of Biotic Interactions

Interactions are categorized by their net fitness effects on survival/reproduction: beneficial (+), harmful (-), or neutral (0).

Mutualism (+/+)

A biotic interaction where both interacting species experience a net fitness benefit.

Obligate vs. Facultative Mutualism

Obligate = species strictly depend on each other for survival/reproduction and cannot live independently; Facultative = beneficial interaction that is optional and context-dependent.

Competition (-/-)

A biotic interaction where both species experience a net fitness reduction due to shared limiting resources.

Intraspecific vs. Interspecific Competition

Intraspecific = competition among individuals of the SAME species (drives density-dependent regulation); Interspecific = competition between DIFFERENT species.

Interference vs. Exploitation Competition

Interference = direct physical interaction or resource guarding (e.g., fight over a carcass); Exploitation = indirect interaction where one species depletes shared resources.

Antagonism (+/-)

A biotic interaction where one species benefits at the direct fitness expense of the other (includes Predation, Herbivory, and Parasitism).

Ectoparasite vs. Endoparasite

Ectoparasites live externally on the host's body (e.g., ticks); Endoparasites live inside the host's body (e.g., tapeworms).

Specialized Parasitic Strategies

Brood Parasitism = laying eggs in another species' nest to raise (e.g., cuckoos); Parasitoidism = larvae live as parasites inside a host and ultimately kill it upon maturing.

Commensalism (+/0) vs. Amensalism (0/-)

Commensalism = one species benefits while the other is unaffected (+/0); Amensalism = one species is harmed while the other is unaffected (0/-).

Apparent Competition (Indirect Interaction)

An indirect (-/-) interaction where two prey species harm each other because an increase in one prey boosts predator numbers, leading to higher predation on the second prey.

Co-evolution

Reciprocal natural selection between interacting species where evolutionary changes in one drive counter-adaptations in the other.

Red Queen Hypothesis

The evolutionary concept that species must constantly adapt and evolve just to maintain relative fitness against co-evolving competitors, predators, and parasites.

Aposematism & Crypsis

Aposematism = bright, conspicuous warning coloration signaling toxicity/danger to predators; Crypsis = camouflage/blending into the environment to avoid detection.

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.

Ecological Niche

The complete functional role, position, and resource use of a species in its environment.

Fundamental vs. Realized Niche

Fundamental Niche = full potential range of conditions a species can occupy without biotic interactions; Realized Niche = actual restricted range occupied due to competition/predation.

Competitive Exclusion Principle (Gause's Law)

Two species competing for the exact same limiting resources cannot stably coexist in the exact same niche; one will competitively exclude the other.

Niche Partitioning

The evolutionary division of shared resources among competing species to minimize competition and allow stable coexistence (includes Morphological, Spatial, Dietary, and Temporal partitioning).

Keystone Species

A species that exerts a disproportionately large control on ecological community structure and diversity relative to its physical abundance; its removal causes community collapse.

Context-Dependent & Optimal Defense Theory

Context-Dependent = producing costly defenses only when predator cues are present (e.g., helmet formation in Daphnia); Optimal Defense = concentrating defenses in vital reproductive/survival organs.

Worldview

The fundamental framework of beliefs, values, and assumptions through which reality is perceived and interpreted.

Knowledge System

A structured, shared way of producing, validating, and transmitting knowledge, including methods, values, relationships, institutions, and language.

Western Science

The systematic study of the physical and natural world through standardized observation, experimentation, hypothesis testing, and peer review.

Strengths of Western Science

Standardized methods, testability, falsifiability, replication, and ability to establish generalizable patterns across systems.

Limitations of Western Science

Cannot determine moral values/ethics ("what should be done") or capture holistic, place-based relational knowledge.

The Myth of Objectivity

Science aspires to objectivity, but questions, methods, and interpretations are human decisions shaped by underlying worldviews, values, and power dynamics.

Key Historical Architects of Western Science

Francis Bacon (linked knowledge to power/control over nature), René Descartes (viewed nature as a machine, separating humans from nature), Isaac Newton (universal mathematical laws).

Historical Link Between Science and Colonialism

Western science historically expanded alongside colonial exploration, resource extraction, and political power structures.

Parachute Science

The practice where researchers extract data/samples from communities and publish/profit without local collaboration, credit, or benefit-sharing.

Knowledge Extraction & Biopiracy

Collecting biological materials, medicines, or local knowledge and patenting or publishing them without community consent or involvement.

Neo-Colonialism

The continuation of colonial patterns where external institutions exert control over decision-making, resource use, and knowledge production.

Indigenous Knowledge Systems (IKS)

Comprehensive, cumulative knowledge of relationships between humans, non-humans, land, and spirit, developed over millennia in specific places.

Place-Based Knowledge

Knowledge that arises from and applies directly to specific local landscapes, where local specificity is a strength rather than a limitation.

Relational Values & Wahkohtowin

Relational values emphasize moral obligations and kin relationships with the land and all living beings; Wahkohtowin (Cree/Métis) means "all my relations."

Honorable Harvest

A practice of taking only what is needed, using it respectfully, giving back, and leaving enough for future generations to flourish.

Indigenous Science (IS)

Systematic investigation of natural phenomena using empirical observation, testing, and verification embedded in relational and land-based frameworks.

Time Horizon of Indigenous Science

Intergenerational (spanning centuries to millennia), focusing on long-term sustainability rather than short-term studies.

Unit of Focus: Western vs. Indigenous Science

Western science is reductionist (isolates specific variables); Indigenous science is holistic (focuses on relationships, networks, and systems).

Purpose of Knowledge: Western vs. Indigenous Science

Western science traditionally aims to explain, predict, and control nature; Indigenous science aims to live sustainably and maintain right relationships with nature.

Etuaptmumk / Two-Eyed Seeing

A concept proposed by Mi'kmaw Elder Albert Marshall to view the world with one eye using the strengths of Indigenous knowledge and the other with Western science for the benefit of all.

Ethical Space

A neutral, respectful framework for bringing distinct knowledge systems together while honoring the authority, autonomy, and values of each.

Indigenous Peoples in Canada

Recognized distinct groups: First Nations (600+ diverse nations), Inuit (Arctic/Inuit Nunangat), and Métis (prairie region, mixed ancestry).

Anthropocene & Great Acceleration

The Anthropocene is the current geological era where human activity is the dominant ecological force; the Great Acceleration (post-1950) is the sharp increase in global human population, resource use, and industrial output

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

Five Direct Drivers of Biodiversity Loss

1) Habitat destruction and fragmentation, 2) Direct overexploitation, 3) Pollution, 4) Invasive species, and 5) Climate change

Habitat Fragmentation & Edge Effects

Fragmentation breaks continuous habitat into isolated patches; Edge Effects create environmental changes at fragment borders, increasing predation, microclimate shifts, and invasive access

Overexploitation

Occurs when the harvesting or removal rate of a population exceeds its natural capacity to replace itself through reproduction (e.g., Atlantic Cod collapse)

DDT Bioaccumulation & Biomagnification

Synthetic pesticides run off into waterways and concentrate up food webs, causing shell thinning in raptors; its ban led to species recovery (e.g., Peregrine Falcons)

Enemy Release Hypothesis

Theory that invasive species thrive in new areas because they leave behind their native predators, parasites, and pathogens, allowing energy redirection to reproduction

Novel Weapon Hypothesis

Theory that invasive species possess unique biochemicals or competitive traits that native species have no evolutionary resistance against

Extinction Vortex

A self-reinforcing downward spiral where small population size leads to genetic drift, inbreeding, lost genetic diversity, and reduced fitness, driving further population decline toward extinction

Organismal Responses to Climate Change

Organisms respond to warming temperatures by shifting ranges (Move), expressing phenotypic plasticity (Adjust), adapting over generations (Evolve), or suffering local extinction (Die)Phenology & Phenological Mismatch

Range Shifts driven by Climate Change

As climate and ice conditions change, species shift geographic distributions toward higher latitudes or elevations, altering local food webs (e.g., Arctic expansion of killer whales)

Population-Level Conservation Interventions

Direct species management tactics including captive breeding, translocation, genetic rescue, harvest restrictions, disease management, and invasive predator removal

Habitat-Level Conservation Interventions

Landscape-scale protections including establishing protected areas, habitat restoration, maintaining wildlife corridors, prescribed fires, and watershed management

30x30 Global Conservation Target

An international goal to protect and sustainably manage at least 30% of Earth's terrestrial and marine ecosystems by the year 2030

IPCAs (Indigenous Protected and Conserved Areas)

Lands and waters conserved through Indigenous leadership, stewardship, and governance; recognized as Canada's primary pathway to meeting 30x30 targets

Limitations of Canadian Conservation Legislation

Environmental laws (like SARA) are often constrained by slow implementation, reactive rather than proactive listings, economic pressures, and historical exclusion of Indigenous stewardship