Ch. 18 sec. 1 Answers 1. Define: Ecology The study of the interactions between organisms and the living and non-living components of their environment. 2. How did our ancestors collect food before the development of agriculture? Our ancestors obtained all of their food by hunting animals and gathering plants, seeds, berries, and nuts. 3. What do ecologists mean by interconnectedness or interdependence? All organisms interact with other organisms in their surroundings and with the nonliving portion of their environment. Their survival depends on these interactions. 4. What is the relationship between acorns in forests in the eastern United States and the spread of Lyme disease? 5. What do ecological models do? Represent or describe the components of an ecological systemhelp them understand environmental interactions and to make predictions about possible changes. 6. List the levels of organization in the environment, from most specific to the broadest. 7. What makes up the biosphere? The thin volume of Earth and its atmosphere that supports life. * Thin! 5-6 miles up to the bottom of the oceans 8. What does an ecosystem include? All of the organisms and the non- living environment found in a particular place. 9. What does a community include? All the interacting organisms living in an area. 10. What does a population include? All the members in a species that live in one place at one time.