Ch 6 Ecology Lecture Flashcards

Vocabulary-style flashcards covering the fundamental concepts of ecology, including ecosystems, energy transfer, biogeochemical cycles, biomes, population dynamics, and human environmental impacts.

Ecology

The study of how living things interact with each other and with their environment.

Abiotic factors

The nonliving aspects of the environment such as sunlight, soil, temperature, and water.

Biotic factors

The living aspects of the environment, consisting of other organisms including members of the same and different species.

Ecosystem

A unit of nature and focus of study in ecology that consists of all the biotic and abiotic factors in an area and their interactions.

Niche

The role of a species in its ecosystem, including all the ways the species interacts with the biotic and abiotic factors of the environment.

Habitat

The physical environment in which a species lives and to which it is adapted.

Competitive exclusion principle

The rule that two different species cannot occupy the same niche in the same place for very long because they would compete for the same resources.

Character displacement

The development of different specializations by two species within the same area to avoid competition and coexist.

Producers (Autotrophs)

Organisms that use energy and simple inorganic molecules to make organic compounds (food) for themselves and others.

Photoautotrophs

Autotrophs like plants, algae, and certain bacteria that use energy from sunlight to make food through photosynthesis.

Chemoautotrophs

Autotrophs like some bacteria and archaea that use energy from chemical compounds to make food through chemosynthesis.

Consumers (Heterotrophs)

Organisms that depend on other organisms for food by taking in organic molecules, including all animals and fungi.

Obligate carnivores

Carnivores that are unable to digest plants and must eat only animals.

Decomposers

Organisms that break down the remains and wastes of dead organisms to release simple inorganic molecules back into the environment.

Scavengers

Decomposers that consume the soft tissues of dead animals, such as vultures and blowflies.

Detritivores

Decomposers that consume detritus, which includes dead leaves, animal feces, and other organic debris.

Saprotrophs

The final step in decomposition; organisms like fungi and bacteria that feed on any remaining organic matter.

Food chain

A diagram representing a single pathway by which energy and matter flow through an ecosystem.

Food web

A diagram representing multiple intersecting pathways through which energy and matter flow through an ecosystem.

Trophic levels

The feeding positions in a food chain or web, generally limited to a maximum of four levels.

Biomass

The total mass of organisms at a specific trophic level.

The $10\,\%$ Rule

The principle that generally only about $10\,\%$ of the energy at one trophic level is available to the next level.

Biogeochemical cycles

Processes by which chemical elements and water are continuously recycled through the biotic and abiotic parts of an ecosystem.

Exchange pool

A part of a biogeochemical cycle that holds an element or water for a short period of time, such as the atmosphere for water.

Reservoir

A part of a cycle that holds an element or water for a long period of time, such as the ocean for water.

Sublimation

The process in the water cycle where ice and snow change directly into water vapor due to heat from the sun.

Transpiration

The process where plants release water vapor through leaf pores called stomata.

Aquifer

An underground layer of rock that stores water, sometimes for thousands of years.

Nitrogen fixation

The process where bacteria transform nitrogen gas ($N_2$) into useful, solid forms like ammonium.

Ammonification

The process by which nitrogen-fixing bacteria in plant roots turn nitrogen gas into ammonium.

Nitrification

The two-step process where nitrifying bacteria change ammonium ions into nitrites and nitrates.

Denitrification

The process where denitrifying bacteria convert nitrates in the soil back into nitrogen gas.

Biome

A group of similar ecosystems with the same general abiotic factors and primary producers.

Climate

The average weather in an area over a long period of time, generally described in terms of temperature and moisture.

Growing season

The period of time each year when it is warm and wet enough for plants to grow.

Biodiversity

The variety of life and its processes, including species diversity, genetic diversity, and ecosystem diversity.

Dormancy

A state in which a plant slows down cellular activities and may shed its leaves to survive cold climates.

Photic zone

The area of water extending to a maximum depth of $200\,m$ where enough sunlight penetrates for photosynthesis to occur.

Aphotic zone

Water deeper than $200\,m$ where little to no sunlight penetrates, preventing photosynthesis.

Benthic zone

The ocean floor where aquatic organisms die and sink; includes decomposers and scavengers that cycle nutrients.

Intertidal zone

 The narrow strip along the coastline covered by water at high tide and exposed to air at low tide.

Wetland

An area saturated or covered by water for at least one season of the year that helps store flood water and remove excess nutrients.

Estuary

A partly enclosed coastal body of water where rivers or streams meet and mix with the ocean.

Plankton

Tiny aquatic organisms that cannot move on their own and live in the photic zone.

Nekton

Aquatic animals that can move on their own by swimming through the water in the photic or aphotic zones.

Benthos

Aquatic organisms that crawl in sediments at the bottom of a body of water.

Predation

A relationship in which members of the predator species consume members of the prey species.

Limiting factor

A factor that restricts the growth or development of an organism, population, or process.

Keystone species

A species that plays an especially important role in its community, where major changes in its population affect many other species.

Intraspecific competition

Competition occurring between members of the same species for resources like food, water, or mates.

Interspecific competition

Competition occurring between members of different species for the same resources.

Symbiosis

A close relationship between two species in which at least one species benefits; includes mutualism, commensalism, and parasitism.

Mutualism

A symbiotic relationship in which both species benefit, such as flowering plants and their pollinators.

Commensalism

A symbiotic relationship in which one species benefits while the other species is not affected.

Parasitism

A symbiotic relationship in which the parasite benefits while the host is harmed.

Ecological succession

The process by which the numbers and types of species in a community change over time.

Primary succession

Succession occurring in an area that has never before been colonized, typically starting with bare rock.

Pioneer species

The first species to colonize a disturbed or new area, such as bacteria, lichens, and mosses on bare rock.

Secondary succession

Succession occurring in a formerly inhabited area that was disturbed by events like fire, flood, or farming.

Population density

The average number of individuals in a population per unit of area or volume.

Survivorship curves

Graphs representing the number of individuals still alive at each age, reflecting death rates at different ages.

Population growth rate formula

$r = (b + i) - (d + e)$ where $b$ is birth rate, $i$ is immigration, $d$ is death rate, and $e$ is emigration.

Logistic growth

A growth pattern where population growth slows and levels off as the population size reaches the carrying capacity.

Carrying capacity (K)

The largest population size that can be supported in an area without harming the environment.

Demographic transition

The process of change in a population from high birth and death rates to low birth and death rates.

Sustainable use

The use of resources in a way that meets the needs of the present and also preserves the resources for future generations.

Algal blooms

Excessive growth of algae caused by added nutrients from fertilizer runoff, which can lead to dead zones.

Acid rain

Precipitation with a low pH caused by nitrogen and sulfur oxides combining with water in the air.

Greenhouse effect

A natural feature where atmospheric gases radiate the sun's heat back down to Earth's surface, preventing it from escaping into space.