All flashcards
Flashcard 1: What is carrying capacity (K) for a population in a habitat?
Answer: The maximum population size the available resources can support. Resources set the upper limit for sustainable population size.
Flashcard 2: What is the most direct effect of decreased water availability on a population size?
Answer: Population size tends to decrease. Water scarcity causes dehydration, reducing survival and reproduction.
Flashcard 3: Choose the word that completes the statement: If resources increase, carrying capacity usually .
Answer: Increases. More resources allow the environment to support larger populations.
Flashcard 4: Which observation best supports that disease spread is density-dependent: outbreaks at high density or equal outbreaks at all densities?
Answer: Outbreaks at high density. Disease spreads more easily when individuals are crowded together.
Flashcard 5: Which option is density-independent: competition, predation, or hurricane?
Answer: Hurricane. Natural disasters affect all individuals equally, regardless of crowding.
Flashcard 6: Identify the most likely population response after a drought reduces plant biomass for herbivores.
Answer: Herbivore population size decreases. Less plant food means fewer herbivores can survive.
Flashcard 7: Identify the best evidence that water is limiting a population: crowded nests, dry streams, or low predation rates.
Answer: Dry streams. Lack of water sources directly limits population survival.
Flashcard 8: Which option is density-dependent: disease, drought, or wildfire?
Answer: Disease. Spreads faster in crowded populations, making it density-dependent.
Flashcard 9: Which change most directly suggests the population exceeded K: increased births, increased emigration, or increased resources?
Answer: Increased emigration. Animals leave when resources can't support the population.
Flashcard 10: What is the cause-and-effect relationship between competition and population size as density rises?
Answer: More competition reduces growth, so population size levels off or drops. Limited resources intensify competition, reducing individual fitness.
Flashcard 11: What is the cause-and-effect relationship between predation and prey population size?
Answer: More predation lowers prey survival, decreasing prey population size. Predators remove individuals, directly reducing prey numbers.
Flashcard 12: Identify the best evidence that food is limiting a deer population: stable numbers, many fawns, or many deer are underweight.
Answer: Many deer are underweight. Low body weight indicates insufficient food resources.
Flashcard 13: What is the most direct effect of reduced shelter or nesting sites on a population?
Answer: Lower survival and reproduction, so population size decreases. Without adequate shelter, organisms face higher mortality.
Flashcard 14: Identify the limiting resource if plants are plentiful but nest sites are scarce for birds.
Answer: Nesting sites (shelter). The scarcest resource limits population despite abundant food.
Flashcard 15: What is the most direct effect of increased food availability on a population size?
Answer: Population size tends to increase. More food supports higher birth rates and survival.
Flashcard 16: Which type of population growth occurs as resources become limited near K?
Answer: Logistic growth. Growth slows as competition for scarce resources intensifies near K.
Flashcard 17: Which type of population growth occurs when resources are unlimited?
Answer: Exponential growth. Without resource limits, populations grow rapidly without constraint.
Flashcard 18: Identify the limiting resource: plants decline after drought, and herbivore numbers drop soon after.
Answer: Food (plant biomass). Herbivores depend on plants; drought reduces plant food supply.
Flashcard 19: What is the expected population effect when a new water source is added to a habitat?
Answer: Population size tends to increase until a new limiting factor appears. Removing one limit allows growth until another limit is reached.
Flashcard 20: What is the most direct evidence that a population exceeded carrying capacity?
Answer: Resource shortages followed by increased deaths and population decline. Overpopulation depletes resources, causing die-offs.
Flashcard 21: What is one density-independent factor that can reduce population size regardless of density?
Answer: Drought, flood, wildfire, or extreme temperature. Natural disasters affect populations regardless of size.
Flashcard 22: What is one density-dependent factor that directly involves resources?
Answer: Competition for limited food, water, or space. More individuals means less resources per organism.
Flashcard 23: Which type of limiting factor does not depend on population density: density-dependent or density-independent?
Answer: Density-independent. Affects all individuals equally regardless of crowding (e.g., weather).
Flashcard 24: Which type of limiting factor depends on population density: density-dependent or density-independent?
Answer: Density-dependent. Effects intensify as population density increases (e.g., competition).
Flashcard 25: Which term describes an organism’s need for food, water, and space: resource or habitat?
Answer: Resource. Resources are materials organisms need; habitat is where they live.
Flashcard 26: What is a limiting factor in population growth?
Answer: Any resource or condition that restricts population size or growth. Examples include food, water, space, predators, or disease.
Flashcard 27: What is the carrying capacity of an ecosystem?
Answer: The maximum population size the environment can support long term. Determined by available resources like food, water, and space.
Flashcard 28: What is the expected effect on population size when predators increase but prey resources stay constant?
Answer: Prey population decreases due to higher predation pressure. More predators means more prey are eaten.
Flashcard 29: Which evidence best supports that space is limiting: population declines after habitat area is reduced, even with enough food?
Answer: Decline after habitat loss indicates space is the limiting resource. Shows space limits population even with adequate food.
Flashcard 30: What pattern indicates a boom-and-bust cycle caused by resource depletion?
Answer: Rapid population increase followed by a sharp decline. Resources support growth, then crash when depleted.