Biology Ecology & Evolutionary Processes Flashcards
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Read the first 7 Biology Ecology & Evolutionary Processes flashcards as text
Which type of symbiosis occurs when one organism benefits and the other is neither helped nor harmed?
Answer: Commensalism
Commensalism is a symbiotic relationship where one species benefits and the other experiences no significant effect.
The competitive exclusion principle states that two species competing for the same limited resource cannot:
Answer: Coexist in the same habitat indefinitely
Gause's competitive exclusion principle holds that two species occupying the exact same ecological niche cannot stably coexist — one will outcompete and displace the other.
In a food web, which trophic level contains the greatest total biomass?
Answer: Primary producers
Primary producers (plants and other autotrophs) form the base of the energy pyramid and contain the greatest biomass because energy is lost at each trophic level.
Which evolutionary mechanism results in the random change of allele frequencies in a small population?
Answer: Genetic drift
Genetic drift refers to random fluctuations in allele frequencies that are especially pronounced in small populations, potentially causing alleles to be lost or fixed by chance.
The concept of 'survival of the fittest' in evolutionary biology most precisely means:
Answer: Individuals with the highest reproductive success in their environment
Fitness in evolutionary biology refers specifically to an organism's reproductive success — its ability to survive and pass on its genes to the next generation.
Which biogeochemical cycle involves the conversion of atmospheric N₂ into ammonia by bacteria?
Answer: Nitrogen cycle
Nitrogen fixation, carried out by bacteria such as Rhizobium, converts atmospheric N₂ into ammonia (NH₃), making nitrogen available to plants.
Allopatric speciation differs from sympatric speciation primarily because allopatric speciation requires:
Answer: Geographic separation of populations
Allopatric speciation occurs when a geographic barrier physically separates a population, allowing the two groups to diverge independently until they become reproductively isolated.