Grade 4 Life Science - Changes to Ecosystems

Question 1

when two or more species fight for the same limited resources (food, water, space, shelter)

Answer 1

competition

Question 2

the gradual change from one ecosystem to another; when the environment changes over time

Answer 2

succession

Question 3

succession that occurs on surfaces where there is rock, no soil exists at first

Answer 3

primary succession

Question 4

succession that occurs in an ecosystem that was damaged but some soil remained

Answer 4

secondary succession

Question 5

living or nonliving things (biotic or abiotic) that help control the growth of population in an ecosystem (food, water, sunlight, air, space, habitat)

Answer 5

limiting factors or resources

Question 6

a species that could become endangered in the near future; population is dropping

Answer 6

threatened

Question 7

a species that is in danger of becoming extinct; population is so low that they may soon be gone forever

Answer 7

endangered

Question 8

an entire species has died out or gone forever; population is zero

Answer 8

extinct

Question 9

species that occur naturally in a particular area

Answer 9

native species

Question 10

a species that is not naturally found in a particular area and may be helpful or harmful to that new ecosystem

Answer 10

introduced species

Question 11

an introduced species that has a negative impact on an ecosystem; takes over an environment

Answer 11

invasive species

Question 12

substances that are very harmful to humans and other organisms

Answer 12

hazardous waste

Question 13

protecting and preserving natural resources and the environment

Answer 13

conservation