Ecological Succession
This type of succession begins on bare rock where no soil exists.
What is primary succession?
These random changes in DNA can introduce new genetic variation into a population.
What are mutations?
An introduced species is less likely to become invasive when these three biological limiting factors are present.
What are predators, parasites, and competitors?
Organisms that use sunlight to make sugars occupy this trophic role.
What are primary producers?
In a food web, arrows indicate the movement of this from one organism to another.
What is energy?
This type of succession occurs after a forest fire when soil remains intact.
What is secondary succession?
This evolutionary process occurs when individuals with advantageous inherited traits survive and reproduce more successfully.
What is natural selection?
Several species of lemurs eat different parts of the same bamboo plant, reducing competition for food.
What is resource partitioning?
In the food chain grass → rabbit → coyote, the rabbit and coyote occupy these consumer levels.
What are primary consumer and secondary consumer?
In the exam food web, these three top consumers would generally have relatively small populations because less energy reaches their trophic levels.
What are the alligator, bobcat, and anhinga?
These first organisms, such as lichens and mosses, help colonize bare rock and eventually contribute to soil formation.
What are pioneer species?
In an isolated wolf population, black fur becomes more common over generations because of random changes in inherited trait frequencies rather than an identified survival advantage.
What is genetic drift?
This process occurs when two interacting species exert evolutionary pressures on one another, such as bamboo developing stronger chemical defenses and lemurs evolving greater toxin tolerance.
What is coevolution?
Only this approximate percentage of energy is transferred to the next trophic level.
What is 10%?
A food web is more realistic than a food chain because it represents this feature of an ecosystem.
What are multiple interconnected feeding relationships and pathways of energy transfer?
A landslide exposes bare rock, while a wildfire destroys an existing forest but leaves the soil. Which area will generally recover faster, and why?
What is the forest, because secondary succession begins with existing soil and potentially surviving organisms?
After dinosaurs went extinct, surviving organisms evolved to occupy ecological roles that had become available. What are these ecological roles called?
What are niches?
The full range of resources and conditions a species could use is its fundamental niche. The portion it actually occupies because of competition and other interactions is called this.
What is the realized niche?
A producer has 10,000 units of energy. Approximately how much will reach a secondary consumer, assuming the 10% rule?
What is 100 units of energy?
If alligators disappear from the food web, what might happen to frogs, moorhens, bass, and the organisms they consume?
The populations of some prey species may increase, placing additional pressure on their own food sources and producing indirect effects throughout the web.
Explain why primary succession generally takes longer than secondary succession, using at least three ecological terms.
Primary succession begins without developed soil. Pioneer species help establish conditions for other plants. Secondary succession begins with existing soil, allowing grasses, shrubs, and trees to return more quickly.
A population of mammoths becomes isolated on an island and eventually develops into a distinct species. Explain the evolutionary process.
What is allopatric speciation, where geographic isolation reduces gene flow and populations diverge over generations until they become reproductively isolated?
Wolverines live in isolated mountain habitats but have not developed into separate species. What ability might explain why geographic separation has not resulted in speciation?
What is long-distance dispersal, allowing gene flow between populations and helping maintain genetic connections?
Why might grasslands support more large herbivores and carnivores than northern pine forests, even when forests contain substantial plant biomass?
What is greater availability of consumable plant energy in grasslands, while much forest biomass is stored in woody material that most herbivores cannot easily eat?
After wolves returned to Yellowstone, elk grazing pressure on willows decreased and willow-nesting birds returned. What ecological phenomenon does this demonstrate?
What is a trophic cascade, in which a top predator indirectly affects organisms at lower trophic levels?