Essay on Food Chain and Trophic Level

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Bio I
Name KEY

Unit 7: Ecology

3.1 What Is Ecology?
Studying Our Living Planet
1. What is ecology? It is the scientific study of interactions among organisms and between organism and their environment. 2. What does the biosphere contain? It contains all the organisms and physical environments of the Earth.

3. How are human economics and ecology linked? Economics has to do with human “houses” and interactions based on money and trade. Ecological interactions have to do with nature’s “houses” and are based on energy and nutrients. Humans depend on ecological processes to provide nutrients that can be bought or traded. 4. Label each level of organization on the diagram.

biosphere biome


population individual/species community

5. Explain the relationship between ecosystems and biomes. An ecosystem describes all of the organisms that live in a place , together with their physical environment. A group of ecosystems that share similar climates and organisms is considered a biome.

Bio I

Unit 7: Ecology

6. Use the terms in the box to fill in the Venn diagram. List parts of the environment that consist of biotic factors, abiotic factors, and some components that are a mixture of both. air animals bacteria heat mushrooms plants
Both Biotic Factors Abiotic Factors

precipitation soil sunlight

animals, plants, mushrooms, bacteria


sunlight, heat, precipitation, air

3.2 Energy, Producers, and Consumers
Primary Producers
7. What do autotrophs do during photosynthesis? They use light energy to power chemical reactions that convert carbon dioxide and water into oxygen and energy rich carbohydrates such as sugars and starch. 8. What do autotrophs do during chemosynthesis? They use chemical energy to produce energy rich carbohydrates.

9. Complete the table about types of heterotrophs. Types of Heterotrophs Type Herbivore Carnivore Omnivore Detritivore Decomposer Scavenger Definition Heterotroph that obtains energy by eating only plants Heterotroph that eats animals Heterotroph that obtains eats both plants & animals Heterotroph that feeds on detritus Heterotroph that breaks down organic matter Heterotroph that consumes the carcasses of dead animals but does not typically kill them itself Examples cows, rabbits snakes, dogs, owls humans, bears, pigs mites, earthworms, snails, crabs bacteria, fungi

vulture, hyena

Bio I

Unit 7: Ecology

10. What is a consumer? A consumer is any organism that relies on other organisms for energy and nutrients

3.3 Energy Flow in Ecosystems
Food Chains and Food Webs
11. Complete the table about feeding relationships.
Feeding Relationships Relationship
Food Chain Food Web

A series of steps in which organisms transfer energy by eating and being eaten A network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem

Use the food chain to answer Questions 2–4.

12. Explain how energy flows through a food chain. Phytoplankton are photosynthetic organisms. They use energy from the sun to create carbohydrates. The zooplankton eats the phytoplankton to obtain energy. The small fish eat the zooplankton. The squid eats the small fish. The shark eats the squid. 13. What would happen to a food chain if a disturbance caused a serious decline in the population of a high level consumer? If the shark numbers declined, there would be no natural predators to control the number of squids. Therefore