WorksheetsLS2.1 Impact of Environmental Variables on Population Size
Total questions: 18
Worksheet time: 10mins
Select the environmental variables that can change how big or small a population gets.
Resource availability, predation, and climate factors
Genetic mutation, inbreeding, and genetic drift
Migration patterns, evolutionary history, and mutualism
Social structure, mating systems, and parental care
In a drought, plants may wilt or die affecting the animals that rely on them.
Plants wilt or die and animals lose their food source.
Plants grow faster and animals increase in number.
There is no impact on plants or animals.
Animals thrive despite changes in vegetation.
True or False: A lot of rain can lead to an increase in plant growth and animal population.
True
False
In 1926, what happened to the wolves in Yellowstone?
They were reintroduced
They were removed
They increased in number
They migrated naturally.
What was the effect of reintroducing wolves in 1995?
Increased elk population
Controlled elk population
Decreased plant growth
Reduced wildlife diversity
Post-1995, the ecosystem experienced changes due to fewer elk. Which of the following best describes these changes?
A reduction in elk numbers led to increased vegetation and altered predator-prey dynamics.
There was no noticeable change in the ecosystem.
An increase in elk numbers resulted in overgrazing.
The ecosystem completely collapsed due to the absence of elk.
Which of the following best describes the significance of the changes in Yellowstone's ecosystem after the reintroduction of wolves?
It initiated a trophic cascade leading to ecological balance.
It had negligible impact on the ecosystem.
It resulted in the immediate decline of predator species.
It created irreversible damage to the landscape.
According to the passage, what can too much rain cause?
Growth of more plants
Flooding and damage to habitats
Increase in animal population
Decrease in water levels.
Some insects thrive while others perish according to the passage because they possess advantageous adaptations.
They possess advantageous adaptations.
They are inherently weaker.
They get lucky.
They run faster.
True or False: More rain always means more animals.
True
False
What is the term used to describe this chain reaction?
Trophic cascade
Ecosystem balance
Food web
Population dynamics
Understanding these relationships is important because they demonstrate the interconnected effects across trophic levels; for instance, an increase in wolves can decrease deer, which in turn allows more trees to grow, and excessive trees can change the soil.
They demonstrate the interconnected effects across trophic levels.
They solely explain the behavior of trees in the forest.
They indicate that soil conditions only affect plant growth.
They only describe the impact on deer populations.
A decrease in the number of wolves might result in which of the following?
Increase in prey population
Decrease in prey population
No change in prey population
Increase in wolf population
Students study a rabbit population graph. They observe a dramatic decrease in the number of rabbits starting in 1924. Select the three factors that may have caused this decrease in the rabbit population.
an increase in the predator population
an increase in the producer population
a disease in the rabbit population
a slight decrease in the rainfall
a decrease in the producer population
Which graph correctly shows how the number of gray wolf sightings would change if more rabbits were available beginning in 1993?
Graph B
Graph C
Graph D
In the graph labeled D, which year shows the lowest number of Gray Wolf sightings? Select the appropriate year.
2001
2003
2005
2007
Temperature affects the development of sea-turtle eggs. Eggs that are incubated at warmer temperatures are more likely to become females. Eggs incubated at cooler temperatures are more likely to become males. How would higher atmospheric carbon dioxide concentrations most likely affect sea turtle populations?
Earth’s climate would be warmer, so the percentage of female turtles would increase.
Earth’s climate would be cooler, so the percentage of female turtles would increase.
Earth’s climate would be warmer, so the percentage of female turtles would decrease.
Earth’s climate would be cooler, so the percentage of female turtles would decrease.
A population of salamanders that live in a river require clear, fresh water to survive. A flood causes tons of sediment to be suspended in the river. Which of these most likely will happen to the salamander population?
