Bio unit test #2

Ecology

The branch of biology that studies how organisms interact with one another and with their physical environment.

Habitat

The specific physical area or environment where an organism lives and finds the resources it needs to survive.

Biomes

Large, naturally occurring communities of flora and fauna occupying major habitats defined by climate, soil, and vegetation.

Temperate Forest

A mid-latitude forest biome characterized by four distinct seasons, moderate rainfall, and a mix of deciduous trees and conifers.

Precipitation

Any form of water—such as rain, snow, sleet, or hail—that falls from clouds to the Earth's surface.

Evaporation

The physical process by which liquid water transforms into water vapor and enters the atmosphere.

Acclimation

Short-term, reversible physiological or behavioral changes an individual organism makes to adjust to an environmental change within its lifetime.

Adaptation

A heritable evolutionary trait in a population that improves survival and reproduction over generations through natural selection.

Abiotic Factors

Non-living physical and chemical components of an ecosystem, such as sunlight, temperature, water, and soil pH.

Biotic Factors

Living or once-living biological components of an ecosystem, such as plants, animals, fungi, and bacteria.

Photosynthesis

The chemical process by which autotrophs convert light energy, carbon dioxide, and water into chemical energy and oxygen: $6\text{CO}_2 + 6\text{H}_2\text{O} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2$.

Cellular Respiration

The metabolic process by which cells break down glucose using oxygen to release usable chemical energy, carbon dioxide, and water: $\text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2 \rightarrow 6\text{CO}_2 + 6\text{H}_2\text{O}$.

Primary Producer (Autotroph)

An organism that produces its own organic food molecules from inorganic sources, such as plants using sunlight or chemotrophic bacteria.

Consumer (Heterotroph)

An organism that cannot synthesize its own food and must obtain energy by consuming other organisms.

Primary Consumer

A herbivore that feeds exclusively on autotrophic primary producers.

Secondary Consumer

An organism that feeds on primary consumers, encompassing both carnivores and omnivores.

Predator-Prey Interaction

A biological interaction in which one organism hunts, kills, and consumes another organism.

Decomposers

Organisms, primarily fungi and bacteria, that break down dead organic matter and waste into simpler chemical nutrients, recycling them back into the ecosystem.

Biomass

The total dry mass of living organic matter within a given area or trophic level at a specific time.

Trophic Pyramids

Graphical representations showing the biomass, energy content, or number of organisms across successive trophic levels in an ecosystem.

Ten Percent Rule

The ecological principle stating that approximately $10\%$ of the energy at one trophic level is transferred to the next higher level, with the remaining $\sim 90\%$ lost primarily as heat during metabolic processes.

Parasitism

A symbiotic relationship where one organism benefits at the expense of a host organism, which is harmed.

Commensalism

A symbiotic relationship in which one organism benefits while the other is neither helped nor harmed.

Mutualism

A symbiotic relationship in which both participating species derive a mutual fitness benefit.

Intraspecific Competition

Competition for limited resources among individuals belonging to the same species.

Interspecific Competition

Competition for limited resources between individuals of different species.

Water Cycle

The continuous movement of water on, above, and below Earth's surface via evaporation, transpiration, condensation, precipitation, and runoff.

Carbon Cycle

The biogeochemical cycle by which carbon moves through the atmosphere, oceans, soil, and living organisms via photosynthesis, respiration, decomposition, and combustion.

Nitrogen Cycle

The biogeochemical process by which nitrogen moves between the atmosphere, soil, and organisms through fixation, nitrification, assimilation, and denitrification.

Nitrogen Gas ($\text{N}_2$)

An unreactive diatomic gas constituting approximately $78\%$ of Earth's atmosphere that cannot be directly assimilated by most plants or animals.

Nitrogen-Fixing Bacteria

Microorganisms, such as Rhizobium in legume root nodules, that convert atmospheric nitrogen gas ($\text{N}_2$) into bioavailable compounds like ammonia ($\text{NH}_3$).

Haber-Bosch Process

An industrial chemical process that synthesizes ammonia from atmospheric nitrogen gas ($\text{N}_2$) and hydrogen gas ($\text{H}_2$) for the manufacture of synthetic fertilizers.

Population Density

The number of individuals of a specific species living per unit of geographic area or volume.

Carrying Capacity ($K$)

The maximum population size of a species that a specific environment can sustainably support over time without degrading habitat resources.

Limiting Factors

Environmental resources or conditions that restrict the growth, abundance, or geographic distribution of an organism or population.

Density-Dependent Factors

Ecological factors whose limiting impact on population growth varies according to population density, such as disease, competition, and predation.

Density-Independent Factors

Environmental factors that alter population size regardless of population density, such as natural disasters, extreme weather, and habitat destruction.

Exponential Growth Curve ($J\text{-curve}$)

Rapid, accelerating population growth that occurs under ideal conditions with unrestricted resource availability.

Logistic Growth Curve ($S\text{-curve}$)

Population growth that accelerates rapidly at first, slows as resources become limited, and eventually stabilizes near the carrying capacity ($K$).

r-selected Species

Species adapted to unstable or variable environments that reproduce rapidly, producing numerous small offspring with minimal parental investment.

K-selected Species

Species adapted to stable environments near carrying capacity that reproduce slowly, producing few large offspring with high parental investment.

Type I Survivorship Curve

A survivorship curve characterized by high survival rates throughout early and middle life, followed by high mortality in old age.

Type II Survivorship Curve

A survivorship curve showing a constant mortality rate across an organism's entire lifespan.

Type III Survivorship Curve

A survivorship curve characterized by high juvenile mortality, with high survival rates for the few individuals that reach adulthood.

Keystone Species

A species that exerts a disproportionately large impact on community structure and biodiversity relative to its numerical abundance.

Invasive Species

Non-native organisms introduced to an ecosystem that proliferate rapidly, outcompete native taxa, and disrupt ecological balance.

Biodiversity

The variety of life across a habitat, region, or ecosystem, encompassing genetic, species, and ecosystem diversity.

Primary Succession

Ecological colonization and development that occurs on newly exposed surfaces devoid of pre-existing life and organic soil.

Secondary Succession

Ecological recovery and re-establishment occurring in an area where a disturbance removed an existing community but left the soil layer intact.

Species Richness

The total count of distinct species present within a defined community or ecosystem.

Species Abundance (Relative Abundance)

The proportion or count of individual organisms of a given species relative to the total number of individuals in that community.

Ecosystem Richness

The variety or total count of different ecosystem types present across a regional landscape.

Ecosystem Abundance

The relative quantity or spatial coverage of a specific ecosystem type across a geographic area.