Science 4th gr - Chapter 4 How do Chang4es in Ecosystems Affect Our World
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42 terms
Terms | Definitions |
|---|---|
 observing | watching - allows you to collect data |
| cause | why something happens |
| effect | what 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. |
| Define competition | 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. | Living space. |
| 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. |
| parasite | An organism that lives on or in another organism, helping itself but hurting the other organism. |
| host | 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. |
| succession | 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. |
| extinct | 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. |
| endangered | 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. |
| hazardous waste | 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. |
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