watching - allows you to collect data
why something happens
How are ecosystems balanced?
All living things depend on one another and their environment to live and grow. Interactions among living and nonliving things help maintain balance in ecosystems.
What do all plants and animals need?
All plants and animals need food, water, living space, shelter, light, and air to grow and be healthy.
Where do living things get what they need?
Living things get what they need from the environment in which they live.
When are ecosystems healthy?
Ecosystems are healthy when all their parts are in balance.
What helps keep the balance of an ecosystem?
All organisms help keep the balance of an ecosystem. Change helps keep ecosytems in balance.
What happens when the number of organisms in a population increases?
There would not be enough food or room to go around.
What are two things that might prevent a plant population from growing in size?
They may not have enough space, water or sunlight.
How do organisms interact?
Organisms in an ecosytem compete for and share resources.
When two or more species in an ecosytem must use the same limited resources.
What happens to the organism that competes successfully?
It is more likely to survive and reproduce.
Name a cause of competition.
What are two behaviors that help animals avoid or reduce competition?
Hunting at different times (hawks during the day, owls at night) and living in groups (can make it easier to obtain food or stay protected).
Can living together side by side be helpful for different organisms?
Yes, two different organisms can live closely together for most or all of their lives.
An organism that lives on or in another organism, helping itself but hurting the other organism.
An organism that is harmed by a parasite.
What might happen to the parasite if its host were to die?
It might die.
How do environments change?
Environments naturally change over time. These changes can occur very slowly or very quickly. Changes to an environment can affect ecosystems and the species that inhabit them.
Gradual change from one community or organism to another.
When does succession occur?
When the environment changes. In most cases, succession occurs in stages.
What is climate?
Climate is the average temperature, winds, and rainfall for an area over many years. Climates change very slowly over a long period of time.
No longer living, as an entire species, or no longer active, as a volcano.
What causes a species to become extinct?
A species will become extinct if the species does not change as Earth changes.
What are some things that may cause a species to become extinct?
Climate changes such as volcanoes and meteors. Human activities, habitat destruction and hunting.
A species whose population has been reduced to such small numbers that it is in danger of becoming extinct.
What do fossils show us?
They show us that life on Earth has not always been the same.
Name some natural events that can quickly change the landscape.
Hurricanes, floods, and fires, along with volcanic eruptions and earthquakes.
What happen to species during natural events?
These rapid changes may force species to leave the area because the resources they need are no longer available.
Name two processes that change an environment over a long period of time?
Climate changes and land changes
How do people disturb the balance?
Human activities change environments. When ecosystems change, some organisms die or leave the area. Other organisms adapt to the changes and survive.
What can happen when humans change the environment?
When we change the environment we sometimes upset the balance of ecosystems.
How does water become polluted?
Water becomes polluted when wastes and chemicals get into rivers, lakes, and oceans. Some of these substances enter the water through the sewer systems.
What is the Clean Water Act?
Law passed in 1969 that made it illegal for anyone to put pollutants into water. A fire on the Cuyahoga River in 1969 led to this law.
Substances that are very harmful to humans and other organisms.
What is land reclamation?
Federal law requires this of land disturbed by mining. Companies must replace rock and soil that was removed.
What does the Surface Mining Control and Reclamation Act require?
It requires that coal companies study the ecosystems before any digging begins. They must plan how to restore the land after they finish mining.
What human activities damage the environment?
Mining, garbage, litter, disposing of hazardous wastes.
Name the first national park.
Yellowstone National Park - established in 1872. Most of the park is in Wyoming.
What are some of the effects of habitat destruction?
Plants and animals die, water becomes unsafe to drink, land becomes unusable.
What are some of the things people have done to protect the environment?
Passed laws such as The Clean Water Act and the Surface Mining Control Act. Establish National Parks and wildlife refuges.