Ecology and Population Biology Lecture Notes

This set of vocabulary flashcards covers key concepts in ecology, population dynamics, competition models, biodiversity, urban ecology, and thermal ecology based on the lecture notes.

Ecology

The scientific analysis and study of interactions among organisms and their environment.

Natural Selection Principles

The four foundations of natural selection: variation, inheritance, overproduction, and differential fitness.

Fundamental Niche

The set of environmental conditions (such as food types, nutrient availability, and climate) under which a species could potentially survive and reproduce based on its physiological tolerance.

Realized Niche

The set of environmental conditions that a species actually occupies at a given point in time as a result of limiting factors in its habitat.

Mark-recapture

A sampling technique involving catching a few individuals, marking them, and catching the same number later to see if any of the marked individuals were recaptured.

General Demographic Equation

$$N_{t+1} = N_t + \text{Birth} - \text{Death} + \text{Immigration} - \text{Emigration}$$

Density-dependent Factors

Biological factors such as competition, predation, and disease that affect birth and death rates in proportion to population size.

Density-independent Factors

Abiotic factors such as temperature, precipitation, and fire that affect population size regardless of density.

Cohort

A group of individuals in a population born at the same time.

Type I Survivorship Curve

Characterized by low mortality early in life and fewer offspring.

Type III Survivorship Curve

Characterized by high mortality in early years and a large amount of offspring.

Intraspecific Competition

Competition occurring between individuals of the same species, including exploitative (resource depletion) and interference (direct blocking) competition.

Carrying Capacity ($K$)

The population size an environment can sustain indefinitely, where birth rate equals death rate and population growth is zero.

Logistic Growth

A growth model represented by $rN(1 - \frac{N}{K})$, which includes a brake factor that slows growth as the population size approaches the carrying capacity.

Metapopulations

Interacting sub-populations in suitable habitat areas (patches) surrounded by unsuitable landscape (matrix) where persistence is created by continuous turnover.

Levins Metapopulation Model

A model where the rate of change of existing populations is determined by the probability of immigration ($C$) and the probability of extinction ($E$).

R-selected Species

Species with high reproductive rates, short lifespans, and little parental care; often many offspring die young.

K-selected Species

Species with low reproductive rates, large body sizes, late maturity, and providing care for few offspring.

Gause's Principle

Also known as the competitive exclusion principle, it states that two species with identical ecological requirements cannot coexist indefinitely in the same environment.

Ecological Character Displacement

Species evolving toward a new niche when coexisting to minimize competition.

Optimal Foraging Theory

The theory that natural selection favors efficient foragers who maximize nutrition while minimizing the time and energy spent obtaining food.

Landscape of Fear

The concept that the presence of predators creates behavioral changes in prey, who perceive risk unevenly across the landscape.

Red Queen Hypothesis

The hypothesis that organisms must continually evolve just to maintain fitness against coevolving partners.

Mutualism

An interaction where both partners receive a net fitness benefit, divided into obligate (cannot survive without the partner) and facultative (beneficial but not essential).

Alpha Biodiversity ($\alpha$)

A measure of species richness at a single site.

Endemism

When a species can only be found in one specific place on Earth, common on islands.

Simpson's Diversity Index

A value ranging from $0$ to $1$ representing the probability that two random individuals from a population are different species.

Trophic Level Energy Transfer

The rule that only approximately $10\%$ of energy is transferred to the next trophic level, limiting most ecosystems to $4$-$5$ levels.

Nitrogen Fixation

The process of converting nitrogen gas ($N_2$) into ammonia ($NH_3$), primarily by nitrogen-fixing bacteria in soil and root nodules.

Haber-Bosch Process

An industrial process converting $N_2 + 3H_2 \rightarrow 2NH_3$ for fertilizer, altering the global nitrogen cycle.

Eutrophication

The process where excess nutrients lead to algal blooms and oxygen depletion in water bodies.

Urban Heat Island Effect

The phenomenon where cities are warmer (up to $1$-$7^{\circ}\text{C}$) than surrounding rural areas due to heat absorption, reduced wind, and lack of evapotranspiration.

Operative Temperature ($T_e$)

The body temperature an organism would have in thermal equilibrium with its environment, often measured using physical copper models.

Ectotherms

Organisms whose body temperature is determined by the environment, representing $99\%$ of all animal species.

CT Max

The maximum critical temperature causing loss of coordination or the righting response in an organism.

Thermal Specialist

An organism with a high physiological performance peak but a narrow breadth of temperature tolerance.

Ice-Albedo Feedback

A climate feedback loop where ice reflects sunlight; melting reduces reflection, leading to further warming.

HIPPO

An acronym for the five major threats to biodiversity: Habitat loss, Invasive species, Pollution, Population growth (human), and Overexploitation.

Empty Forest Syndrome

A condition in a forest that appears physically intact but has lost its large animal populations due to overexploitation.