Biology Ecology and Evolution Flashcards
7 cards from real Biology Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Biology Ecology and Evolution flashcards as text
What is 'biological magnification' (biomagnification) in an ecosystem?
Answer: The accumulation of toxins at higher trophic levels
Biomagnification occurs when pollutants like DDT or mercury concentrate at increasingly higher levels as they move up the food chain.
Which concept explains why two species with identical ecological niches cannot coexist in the same habitat?
Answer: Competitive exclusion principle
The competitive exclusion principle states that two species competing for the same limiting resource cannot stably coexist; one will outcompete the other.
What type of natural selection favors individuals at both extremes of a trait distribution over those in the middle?
Answer: Disruptive selection
Disruptive (diversifying) selection increases the frequency of extreme phenotypes and can eventually lead to the divergence of a population into two distinct groups.
How does mutualism differ from commensalism in terms of ecological benefit?
Answer: Mutualism benefits both species; commensalism benefits only one
In mutualism both species gain a fitness benefit (e.g., clownfish and anemones), while in commensalism only one species benefits and the other is unaffected.
In population ecology, what does the logistic growth model add to the exponential growth model?
Answer: Carrying capacity (K)
The logistic model incorporates carrying capacity (K), limiting population growth as resources become scarce and population size approaches the environmental maximum.
Which evolutionary mechanism involves individuals from one population moving to and breeding with another population?
Answer: Gene flow
Gene flow (migration) introduces new alleles into a population and can increase or decrease genetic diversity, countering the effects of drift and selection.
What defines a 'climax community' in ecological succession?
Answer: A stable, self-sustaining community representing the endpoint of succession
A climax community is the relatively stable, mature endpoint of ecological succession that persists until disturbed, characteristic of the regional climate and soil.