WorksheetsStability and Populations
Total questions: 20
Worksheet time: 10mins
The graph shows that the honeybee population was stable and then decreased. Which statement describes births and deaths when the honeybee population was stable?
There was the same amount of births and deaths.
There were more births than deaths.
There were fewer births than deaths.
There were no deaths.
Which statement describes births and deaths when the population was decreasing?
There was the same amount of births and deaths.
There were more births than deaths.
There were fewer births than deaths.
There were no deaths.
What ideas do you have about what could cause the number of births to increase in a population?
Increased number of deaths and birth rate remained the same.
Increased number of births and deaths
Decreased number of births and deaths
Decreased number of deaths and increased number of deaths.
The diagram above is called a food web. It shows the relationship between foxes and voles. What does the food web show?
foxes eat voles
voles eat foxes
voles compete with foxes
foxes compete with voles
Foxes eat small animals called voles. In southern Sweden, scientists observed that when the vole population decreased, what will happen the fox population?
Population will decrease
Population will remain stable
Population will increase
Ecologists gather a lot of evidence from ecosystems. One useful piece of evidence is what each population eats. How do you think knowing “what eats what” helps ecologists to explain changes in population size?
Ecologists need to know what populations eat because changes to the size of consumer or resource populations can change the size of other populations.
Ecologists do not need to know what populations eat because changes to the size of populations can never change.
Ecologists need to know what populations eat because changes to the weather can change the size of populations.
Economist need to know what populations eat because changes to the food web can change the size of other populations.
A population of Tule Elk lives in Bakersfield. Over 150 years, the size of the Tule Elk population decreased. What best explains the decreased in the size of the Tule Elk population?
A lot of Tule Elk were born and none of them died.
The Tule Elk population is always increasing because no animal eats Tule Elk.
Fewer Tule Elk were born than died.
More Tule Elk were born than died
A population of Mountain Lions lives in southern California. Over 20 years, the size of the Mountain Lion population in the region increased. What best explains the increase in the size of the Mountain Lion population?
The Mountain Lions population is always increasing because no animal eats Mountain Lions
More Mountain Lions were born than died.
Fewer Mountain Lions were born than died.
Two organisms fighting for the same resources is known as:
Predation
Symbiosis
Competition
Dancing
When a populations is known to be STABLE, it:
there are more deaths
stays mostly the same, over time
there are more births
horses live there
Energy storage molecules are:
molecules required only for the birth rate
potatoes
a molecule organisms use to stabilize a population
a molecule that organisms can use to release the energy needed to survive
An indirect effect is:
the result of one cause leading to an effect that causes one or more other effects
the result of one cause stopping a desired effect
the result of more than one cause leading to the death rate of a population
when there is a direct relationship between one organism and the next
A scientist who studies ecosystems is known as:
chemist
biologist
ecologist
foodwebologist
A resource population is:
a population that is avoided by organisms
a population that is traded between organisms
a population that is eaten by organisms from another population
a population that is never eaten because it doesn't taste good.
What do you think would happen to the lion population if the hyena population increases in size? Assume that the populations were stable before this change.
The lion population would increase.
The lion population would not change.
The lion population would decrease.
The hyena population would increase.
You’ve already discussed how the zooplankton and sea turtle populations might have caused the size of the moon jelly population to increase. Which other populations do you think could have caused the size of the moon jelly population to increase? (You may choose more than one.)
Kelp
Orca
Sea Urchin
Walleye Pollock
A ________________________________ is all the living and non-living things interacting in a particular area.
Populations
Sample
Ecosystem
Organism
There are 3 populations in a grassland ecosystem: lizards eating fireflies, and fireflies eating gnats (insects). Suddenly, the lizard population decreased. What will probably happen to the size of the population of fireflies
Increase due to fewer energy storage molecules needed by the lizards so they will eat fewer fireflies. Thus, leading to fewer deaths deaths than births in the firefly population
Decrease due to a decrease in any population causes a decrease in the sizes of all other populations in the ecosystem
Stay the same due to the size of the resource population not changing, so the amount of energy storage molecules available for the fireflies did not change. Thus, the number of births and deaths in the firefly population will be the same
Increase due to the lizard population leaving more energy storage molecules available for the firefly population to reproduce more. Thus, leading to more births in the firefly population
In Australia, both opossums and foxes eat rats. The sizes of the populations have been stable for the last 12 years, but recently the size of the opossum population increased. What will likely happen to the fox population?
increase. An increase in the size of any population leads to an increase in the sizes of all other populations in an ecosystem.
decrease. Fewer energy storage molecules will be available to the fox population from the smaller rat population, so the fox population will reproduce less. This will lead to fewer births than deaths in the fox population.
decrease. The larger opossum population will leave fewer energy storage molecules for all other populations in the ecosystem, so the fox population will reproduce less. This will lead to fewer births than deaths in the fox population.
stay the same. Opossums and foxes do not eat each other, so the number of births and deaths in the fox population will stay the same.
In the Arctic Ocean, sharks eat whales, and whales eat crabs. In the last 10 years, the sizes of the populations have been stable, but recently the size of the crab population increased. What will likely happen to the shark population?
The size of the shark population will . . .
decrease. The larger crab population will leave fewer energy storage molecules available in the ecosystem for the shark population, so there would be fewer births in the shark population.
stay the same. Sharks do not eat crabs, so the number of births and deaths in the shark population will stay the same.
increase. More energy storage molecules will be available to the shark population from the larger whale population, so the shark population will reproduce more. This will lead to more births than deaths in the shark population.
increase. An increase in the size of any population leads to an increase in the sizes of all other populations in an ecosystem.
