BIRTHS & DEATHS
A population increases over time. What must be true about births and deaths?
More individuals were born than died.
If a consumer population becomes smaller, how much glucose does it need?
Fewer energy storage molecules (less glucose).
If tiger populations increase, what happens to worms?
WORMS - WILD PIGS - TIGERS
Worms increase because wild pigs decrease and eat fewer worms.
Penguins eat sardines. Sardines eat zooplankton.
If penguins decrease, what happens to zooplankton?
Zooplankton decrease because sardines increase and eat more of them.
What do birds like eagles and hawks need energy for?
Flying, breathing, and digesting food
A deer population decreased over 50 years. What best explains this?
Fewer deer were born than died.
When penguins decreased, what happened to the sardine population? Why?
Sardines increased because fewer were eaten
If hawks increase, what happens to sparrows?
WORMS - SPARROWS - HAWKS
Sparrows decrease because more are eaten.
Sharks eat sea otters. Sea otters eat clams.
If sharks increase, what happens to clams?
Clams increase because sea otters decrease.
What do mammals like tigers and zebras need energy for?
Running, breathing, and digesting food
A squirrel population stayed the same for 50 years. What must be true?
The number born equaled the number that died
If a grasshopper population decreases, what happens to rats that eat them?
Rats decrease because they have fewer energy storage molecules available.
If ants decrease, what happens to anteaters?
GRASS - ANTS- ANTEATERS
Anteaters decrease because ants decrease, leaving less energy available.
Owls and raccoons eat ducks. Ducks eat frogs.
If raccoons decrease, what happens to frogs?
Frogs decrease because ducks increase.
Why do organisms need glucose?
For energy to survive, grow, reproduce, and carry out life processes.
A shark population increased in the Atlantic Ocean. What best explains this?
More sharks were born than died
If snails increase in a river ecosystem, what happens to perch?
Perch increase because more energy storage molecules are available.
If wolves increase and both wolves and coyotes eat deer, what happens to coyotes?
BERRIES - DEER - (WOLVES/COYOTES)
Coyotes decrease because fewer deer are available.
If frogs decrease and spiders also eat flies, what happens to spiders?
Spiders increase because more flies are available
If a population has fewer energy storage molecules available, what happens to reproduction?
Fewer births occur.
A population is shrinking. Complete the statement:
When births are fewer than deaths, the population ______.
Decreases.
Complete this cause and effect chain:
Smaller consumer population → eats less → resource population ______.
Increases.
True or False:
A change in one population can affect populations that are not directly connected to it.
True.
Explain why a change in one predator can affect organisms three levels down in a food web.
Because changes affect births and deaths in connected populations, causing ripple effects throughout the ecosystem.
How are energy storage molecules connected to population size?
More available energy allows more births; less energy leads to fewer births and population decline.