Symbiosis
A small fish gains protection by living among coral, while the coral is unaffected.
What is commensalism?
A plant develops thorns that physically prevent herbivores from feeding.
What is a mechanical defense?
Two oak trees compete for sunlight within the same forest.
What is intraspecific competition?
A bird eats parasites off a large mammal. The bird gains food, and the mammal has reduced parasite load.
What is mutualism?
A species maintains population size by producing many offspring with low survival rates.
What is an r-selected strategy?
A tick feeds on a deer’s blood, weakening the deer over time.
What is parasitism?
A caterpillar produces toxins that make it unpalatable to predators.
What is a chemical defense?
A hawk and a fox both hunt the same rodent species in a habitat.
What is interspecific competition?
A plant benefits from bacteria that fix nitrogen in its roots, but the plant can still survive without the bacteria in nutrient-rich soil.
What is a facultative mutualism?
Individuals with traits better suited to the environment leave more offspring.
What is natural selection?
A fungus and algae live together as a lichen, exchanging nutrients and protection.
What is mutualism?
A skunk sprays a foul-smelling liquid when threatened.
What is a physical (active) defense?
A species uses specific food sources, nesting sites, and active times that define its role in the ecosystem.
What is an ecological niche?
A remora fish attaches to a shark, gaining food scraps while the shark is unaffected.
What is commensalism?
Two extreme phenotypes are favored over intermediate ones in a population.
What is disruptive selection?
A termite dies when its gut protists are removed, showing complete dependence on the interaction.
What is an obligate mutualism?
Two bird species feed on the same limited seeds, reducing each other’s access to food and lowering survival.
What is competition?
Two species of barnacles initially compete for the same space, but one evolves to occupy higher tidal zones, reducing overlap.
What is niche differentiation?
A fungus provides nutrients to an alga, but the alga provides sugars. However, the fungus cannot survive independently.
What is an obligate mutualism?
The intermediate phenotype is favored over the two extreme phenotypes.
What is stabilizing selection?
A parasite requires multiple host species (e.g., human and mosquito) to complete its life cycle. This complexity increases:
What is reproductive success across environments?
Over generations, predators become better at capturing prey, while prey become better at avoiding capture.
What is coevolution?
Two species compete for identical resources. One cannot adapt to reduce overlap and eventually disappears from the habitat.
What is the competitive exclusion principle?
A mutualistic interaction involves three species: a host, a symbiont, and the symbiont’s own internal bacteria.
What is multi-level mutualism?
A small group of individuals colonizes a new island, resulting in reduced genetic variation.
What is the founder effect?