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Table of Contents. Living Things and the Environment Studying Populations Interactions Among Living Things Changes in Communities. Living Things and the Environment. Levels of Organization.
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Table of Contents Living Things and the Environment Studying Populations Interactions Among Living Things Changes in Communities
Living Things and the Environment Levels of Organization The smallest level of organization is a single organism, which belongs to a population that includes other members of its species.
Living Things and the Environment Levels of Organization The population belongs to a community of different species.
Living Things and the Environment Levels of Organization The community and abiotic factors together form an ecosystem.
Living Things and the Environment Identifying Main Ideas As you read about habitats, write the main idea–the biggest or most important idea–in a graphic organizer like the one below. Then write three supporting details that give examples of the main idea. Main Idea An organism obtains food. Detail Detail Detail Each organism must live in a specific type of environment, called its habitat. Organisms live in different habitats because they have different requirements for survival. One area may contain many habitats.
Living Things and the Environment Links on Biotic and Abiotic Factors Click the SciLinks button for links onbiotic and abiotic factors.
Studying Populations Inequalities The population statement is an example of an inequality. An inequality is a mathematical statement that compares two expressions. Two signs that represent inequalities are: < (is less than) > (is greater than) For example, an inequality comparing the fraction to the decimal 0.75 would be written < 0.75
Practice Problems Write an inequality comparing each pair of expressions below. 5 __ –6 5 > –6 Studying Populations Inequalities
Practice Problems Write an inequality comparing each pair of expressions below. 0.4 __ 0.4 < Studying Populations Inequalities
Practice Problems Write an inequality comparing each pair of expressions below. –2 - (–8) __ 7 - 1.5 –2 - (–8) > 7 - 1.5 Studying Populations Inequalities
Studying Populations Changes in Population Size Populations can change in size when new members join the population or when members leave the population.
Studying Populations Changes in Population Activity Click the Active Art button to open a browser window and access Active Art about changes in population.
Studying Populations Changes in Population Density In many situations, it is helpful to know the population density–the number of individuals in a specific area. Population density =
Studying Populations Question Answer Asking Questions Before you read, preview the red headings. In a graphic organizer like the one below, ask a question for each heading. As you read, write the answers to your questions. Some methods of determining population size are direct observation, indirect observation, sampling, and mark-and-recapture studies. How do you determine population size? What causes populations to change in size? Some factors include birth, death, immigration, and emigration. What are limiting factors? These are factors that can limit population growth if they are unfavorable for the organisms in the population. Food and water, space, and weather conditions can be limiting factors.
Interactions Among Living Things Adapting to the Environment Every organism has a variety of adaptations that are suited to its specific living conditions.
Interactions Among Living Things Predator - Prey Interactions On Isle Royale, an island in Lake Superior, the populations of wolves (the predator) and moose (the prey) rise and fall in cycles. Use the graph to answer the questions.
Year; numbers of wolves and moose Reading Graphs: What variable is plotted on the x-axis? What two variables are plotted on the y-axis? Interactions Among Living Things Predator - Prey Interactions
The moose population increased and then decreased; the wolf population increased. Interpreting Data: How did the moose population change between 1965 and 1972? What happened to the wolf population from 1973 through 1976? Interactions Among Living Things Predator - Prey Interactions
As the moose population increased, more food was available to the wolf population and it increased. Inferring: How might the change in the moose population have led to the change in the wolf population? Interactions Among Living Things Predator - Prey Interactions
The wolf population increased. Drawing Conclusions: What is one likely cause of the dip in the moose population between 1974 and 1981? Interactions Among Living Things Predator - Prey Interactions
Disease would cause a decrease in the wolf population, so fewer moose would be eaten and the population could increase. Predicting: How might a disease in the wolf population one year affect the moose population the next year? Interactions Among Living Things Predator - Prey Interactions
Interactions Among Living Things Using Prior Knowledge Before you read, look at the section headings and visuals to see what this section is about. Then write what you know about how living things interact in a graphic organizer like the one below. As you read, continue to write what you learn. What You Know Organisms interact in different ways. What You Learned Organisms are adapted to their environments. Organisms have niches, which are their roles in their habitats. Organisms compete for resources. Some organisms eat others, and this affects the size of populations. Some organisms live together in symbiotic relationships, of which there is mutualism (both benefit), commensalism (one benefits, the other is not helped or harmed), and parasitism (one benefits, the other is harmed).
Interactions Among Living Things More on Population Interactions Click the PHSchool.com button for an activity about population interactions.
Changes in Communities Primary Succession Primary succession is the series of changes that occur in an area where no soil or organisms exist.
Changes in Communities Secondary Succession Secondary succession is the series of changes that occur in an area where the ecosystem has been disturbed, but where soil and organisms still exist.
Changes in Communities Comparing and Contrasting As you read, compare and contrast carbohydrates, proteins, and lipids in a table like the one below. Factors in Succession Primary Succession Secondary Succession Volcanic eruption Fire Possible cause No soil or organisms exist. Soil and organisms exist. Type of area No Yes Existing ecosystem?
Changes in Communities Links on Succession Click the SciLinks button for links on succession.
Graphic Organizer Main Idea There are four main ways to determine the size of a population. Detail Detail Detail Detail Mark-and-recapture studies Direct observation Indirect observation Sampling