Terrestrial Ecosystems, Climate, and Population Biology Flashcards

Flashcards based on terrestrial ecosystems, climate influences, population dynamics, control mechanisms, growth models, and life history strategies from lecture notes.

What is Earth’s axial tilt?

A $23.5^\circ$ tilt on its rotational axis.

What does axial tilt determine?

Seasons, sunrise/sunset patterns, and temporal climate change.

What would Earth be like without axial tilt?

No seasons, loss of biodiversity, and loss of geographic climate diversity.

What are the key geographical variables that influence local climate?

Latitude, Elevation / Altitude, Prevailing winds / air masses, and Proximity to large water bodies.

What is latitude?

Distance north or south of the equator, measured in degrees.

How does latitude affect climate?

Angle of incoming sunlight decreases as you move away from the equator, resulting in less solar energy and cooler temperatures.

How are positive and negative latitudes defined?

North of equator = positive; South of equator = negative.

What is elevation?

Height of land surface above sea level.

What is altitude?

Height of an object above sea or ground level.

How does elevation and altitude affect climate?

Higher elevation/altitude leads to lower air pressure, air expansion, cooling, and colder temperatures.

Do elevation and altitude affect climate the same way?

Yes, both cause cooling due to pressure decrease and air expansion.

What do geographical features within latitudinal zones cause?

Localized variation in precipitation (e.g., rain shadow deserts).

What is the climate at $0^\circ$ (Equator)?

Warm, rising air, heavy precipitation (tropical rainforests).

What is the climate at $30^\circ\text{ N/S}$?

Descending dry air, compressed & warmed, persistent dry conditions (deserts).

What is the climate at $60^\circ\text{ N/S}$?

Subpolar lows, rising moist air, variable weather.

What is the climate at $90^\circ\text{ N/S}$?

Polar highs, extremely cold, high pressure, descending air (N/S Poles)

What is abundance?

How many individuals are present.

What is population density?

Number of individuals per unit area or volume.

What variables predict future population size?

Ecological & environmental factors, age structure, sex ratio, density, dispersion, trajectory over time.

What is age structure?

Distribution of individuals across age classes (cohorts).

What is sex ratio?

Proportion of males to females.

What is a population?

Individuals of the same species inhabiting a specific area.

What are the primary attributes of a population?

Distribution, dispersion, size/density, age structure, sex ratio.

What is distribution?

Geographic range & spatial boundaries of a species.

What is dispersion?

Spatial arrangement of individuals within their range.

What are the patterns of dispersion?

Clumped, Random, Uniform.

What is bottom-up control?

Regulation driven by resource availability at the base of the food web.

What type of population growth is associated with bottom-up control?

Resource-limited population growth.

Is bottom-up control driven by abiotic or biotic factors?

Abiotic factors (light, water, nutrients).

What is top-down control?

Regulation driven by predators, competition &, pathogens.

What type of population growth is associated with top-down control?

Enemy-limited population growth.

Is top-down control driven by abiotic or biotic factors?

Biotic factors.

What is intraspecific competition?

Competition among members of the same species for limited resources.

What is interspecific competition?

Competition between different species for limited resources.

What is exponential growth?

Rapid, accelerating population increase under unlimited resources.

What is intrinsic growth rate ($r$)?

Maximum per-capita growth rate under ideal conditions.

What are the ideal conditions for $r$?

Unlimited resources, no predation, no competition.

What is the simplified equation for $r$?

$r = b - d$ (birth rate minus death rate).

What is logistic growth?

Growth that starts rapidly, then slows and stabilizes at carrying capacity ($K$).

What is carrying capacity ($K$)?

Maximum population size an environment can sustain.

What are density-dependent factors?

limiting factors whose effects increase with population density (e.g., competition, predation).

What are density-independent factors?

limiting factors that affect population size regardless of density (e.g., storms, fires, drought).

What are the traits of K-selected species?

Low reproduction rate, high parental care, long lifespan, slow growth.

What are the traits of r-selected species?

High reproduction rate, little/no parental care, short lifespan, rapid growth.

What is ecology?

Study of how organisms interact with their environment.