Asked by ghiu
DEFINE ALL OF THESE TERMS AND ANSWER THE ONE QUESTION Life expectancy
Fertility rate
Emigration
Immigration
Population
Community
Demography
Mutualism
Commensalism
Predation/parasitism
Competition
Niche
Herbivore
Carnivore
Omnivore
Scavenger
Decomposer
Autotroph
Heterotroph
Food chain
Food web
Energy pyramid
Apex predator
Invasive species
Primary succession
Secondary succession
Climax community
What are the four factors used to forecast population size?
All Answers 1
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Here are short, clear definitions for each term, followed by the answer to the question.
- Life expectancy: The average number of years a person (or organism) of a given age is expected to live based on current mortality rates.
- Fertility rate: Usually refers to the total fertility rate (TFR) — the average number of children a woman is expected to have over her lifetime (or can refer to births per 1,000 population per year).
- Emigration: Leaving one population or geographic area to live in another (outflow of individuals).
- Immigration: Moving into a new population or geographic area from elsewhere (inflow of individuals).
- Population: All individuals of a single species living in a defined area at a given time.
- Community: All populations of different species living and interacting in a particular area.
- Demography: The study of the size, structure, distribution, and trends (births, deaths, migration, etc.) of populations.
- Mutualism: A species interaction in which both participants benefit.
- Commensalism: An interaction where one species benefits and the other is neither helped nor harmed.
- Predation/parasitism: Interactions where one organism (predator or parasite) benefits at the expense of another (prey or host). Predation usually kills the prey quickly; parasitism typically exploits the host over time and may not immediately kill it.
- Competition: When individuals or species vie for the same limited resources (food, space, mates), reducing each other’s growth, survival, or reproduction.
- Niche: The role of a species in its ecosystem — how it obtains resources, its habitat, behavior, and interactions with other species (its “job” and environmental tolerances).
- Herbivore: An organism that primarily eats plants.
- Carnivore: An organism that primarily eats other animals.
- Omnivore: An organism that eats both plants and animals.
- Scavenger: An organism that consumes dead animals or carrion.
- Decomposer: Organisms (bacteria, fungi, some invertebrates) that break down dead organic matter and recycle nutrients back into the ecosystem.
- Autotroph: An organism that produces its own food from inorganic sources (e.g., plants, algae, some bacteria — usually via photosynthesis or chemosynthesis).
- Heterotroph: An organism that obtains energy and organic compounds by consuming other organisms (animals, fungi, many bacteria).
- Food chain: A linear sequence showing who eats whom, transferring energy from one trophic level to the next.
- Food web: A network of interconnected food chains showing multiple feeding relationships in an ecosystem.
- Energy pyramid: A diagram showing energy (or biomass/number) at each trophic level; energy decreases at higher levels (commonly ~90% is lost each transfer, ~10% passed on).
- Apex predator: A top predator with no natural predators in its ecosystem.
- Invasive species: A nonnative species that spreads widely and causes ecological or economic harm in its introduced range.
- Primary succession: Ecological succession that begins on lifeless substrate (no soil), e.g., after lava flow or glacial retreat; pioneer species colonize and gradually build soil.
- Secondary succession: Succession that occurs where a disturbance removed a community but left the soil intact (e.g., after fire, farming, or storm).
- Climax community: A historically used term for a relatively stable, mature community that persists until disrupted; modern ecology recognizes ecosystems often remain dynamic rather than perfectly stable.
Question — What are the four factors used to forecast population size?
- Births (natality/fertility)
- Deaths (mortality)
- Immigration (individuals moving in)
- Emigration (individuals moving out)
Population change = (births + immigration) − (deaths + emigration).
- Life expectancy: The average number of years a person (or organism) of a given age is expected to live based on current mortality rates.
- Fertility rate: Usually refers to the total fertility rate (TFR) — the average number of children a woman is expected to have over her lifetime (or can refer to births per 1,000 population per year).
- Emigration: Leaving one population or geographic area to live in another (outflow of individuals).
- Immigration: Moving into a new population or geographic area from elsewhere (inflow of individuals).
- Population: All individuals of a single species living in a defined area at a given time.
- Community: All populations of different species living and interacting in a particular area.
- Demography: The study of the size, structure, distribution, and trends (births, deaths, migration, etc.) of populations.
- Mutualism: A species interaction in which both participants benefit.
- Commensalism: An interaction where one species benefits and the other is neither helped nor harmed.
- Predation/parasitism: Interactions where one organism (predator or parasite) benefits at the expense of another (prey or host). Predation usually kills the prey quickly; parasitism typically exploits the host over time and may not immediately kill it.
- Competition: When individuals or species vie for the same limited resources (food, space, mates), reducing each other’s growth, survival, or reproduction.
- Niche: The role of a species in its ecosystem — how it obtains resources, its habitat, behavior, and interactions with other species (its “job” and environmental tolerances).
- Herbivore: An organism that primarily eats plants.
- Carnivore: An organism that primarily eats other animals.
- Omnivore: An organism that eats both plants and animals.
- Scavenger: An organism that consumes dead animals or carrion.
- Decomposer: Organisms (bacteria, fungi, some invertebrates) that break down dead organic matter and recycle nutrients back into the ecosystem.
- Autotroph: An organism that produces its own food from inorganic sources (e.g., plants, algae, some bacteria — usually via photosynthesis or chemosynthesis).
- Heterotroph: An organism that obtains energy and organic compounds by consuming other organisms (animals, fungi, many bacteria).
- Food chain: A linear sequence showing who eats whom, transferring energy from one trophic level to the next.
- Food web: A network of interconnected food chains showing multiple feeding relationships in an ecosystem.
- Energy pyramid: A diagram showing energy (or biomass/number) at each trophic level; energy decreases at higher levels (commonly ~90% is lost each transfer, ~10% passed on).
- Apex predator: A top predator with no natural predators in its ecosystem.
- Invasive species: A nonnative species that spreads widely and causes ecological or economic harm in its introduced range.
- Primary succession: Ecological succession that begins on lifeless substrate (no soil), e.g., after lava flow or glacial retreat; pioneer species colonize and gradually build soil.
- Secondary succession: Succession that occurs where a disturbance removed a community but left the soil intact (e.g., after fire, farming, or storm).
- Climax community: A historically used term for a relatively stable, mature community that persists until disrupted; modern ecology recognizes ecosystems often remain dynamic rather than perfectly stable.
Question — What are the four factors used to forecast population size?
- Births (natality/fertility)
- Deaths (mortality)
- Immigration (individuals moving in)
- Emigration (individuals moving out)
Population change = (births + immigration) − (deaths + emigration).
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