4.9AB Producers, Consumers, and Food Webs

Transcription

1 4.9AB Producers, Consumers, and Food Webs Key Concept 1: Producers need sunlight, water, and carbon dioxide to make (produce) their own food. Consumers depend on plants or other organisms for food. Questions: What are producers and what do they need to make their food? What are consumers and where do they get their food? Passage: circle your answer choice. All living things need food. Organisms that make their own food are called plants producers eating carnivores and capture the energy in sunlight. They use the energy to make their carnivores producers own plants food. own plants eating animals are producers. Many organisms get energy by eating animals own plants other organisms. These organisms are called plants own herbivores consumers and do not make their own food. Scientists classify consumers into three groups: plants herbivores own carnivores

2 , carnivores, and omnivores. All animals are consumers and depend on other organisms for food. Study Guide: All living things need food. Organisms that make their own food are called producers and capture the energy in sunlight. They use the energy to make their own food. plants are producers. Many organisms get energy by eating other organisms. These organisms are called consumers and do not make their own food. Scientists classify consumers into three groups: herbivores, carnivores, and omnivores. All animals are consumers and depend on other organisms for food. Illustration: Illustrate an example of a producer and a consumer. Lab Question : Food provides animals with the materials and energy they need for growth, warmth, and motion. Plants get material for growth mostly from air and water, and obtain energy from sunlight. Producers provide food to consumers because Answer: animals cannot produce their own food Write your If/Then statement: Lab Question: Which of the following is NOT needed for a producer to make its own food? ANSWER: OXYGEN. Write your If/Then statement: Lab Question: Producers use sunlight, water, and carbon dioxide in the process of making their own food. Which of the following options correctly matches the components of the process shown in the diagram? Answer: 1 Energy 2 Water 3 Carbon Dioxide 4 Oxygen Write your If/Then statement.

3 Food chains and food webs are the energy pathways within an ecosystem. A food chain shows how each living thing gets its food. For example, a simple food chain in an African grassland ecosystem links the trees and shrubs eaten by the giraffes, which in turn are eaten by the lions. Each link in this chain is food for the next link. A food chain always starts with sunlight and plant life and ends with an animal. Lab Question: A chart listing some of the organisms found in the Tundra ecosystem is shown below. Which food chain correctly identifies the flow of energy? Answer: Write your If/Then statement: Typically, animals eat more than one food source; consequently, the food chains are interwoven into a food web (a connection of food chains with many food energy paths within an ecosystem). Chickens might be

4 food for humans, bacteria, or flies. Each of those flies might be connected to frogs, microbes, or spiders. There are dozens of connections for every organism. When all of the connecting lines are drawn, the result is a web-like shape. Lab Question - A food web from a forest ecosystem is shown below. In the diagram, which of the following organisms would have the greatest impact on the food web if it were removed? Answer: Oak tree Write your If/Then statement:

5 Lab Question: A student has not done the final measurement for a plant in an investigation. How tall is the plant if rounded to the nearest cm? Answer: 13 cm Write your If/Then statement:

6 Key Concept 2: The Sun provides energy that flows through food chains and webs. Energy that moves through a food web originally comes from the Sun. Question: Where does the energy that starts a food chain begin? What is a food web? Where does the energy that starts a food web begin? Passage: circle your answer choice. All organisms need energy. A plant gets its energy from the eats energy Sun cycle. If a grasshopper cycle moves hawk eats the plant, the grasshopper gets the energy that was stored in the plant. If a shrew eats the grasshopper, the shrew gets the energy hawk food cycle that was stored in the grasshopper s body. If a hawk eats the shrew, the hawk gets energy. In this way, energy cycle moves Moon plants from the plant to the grasshopper to the shrew and then to the plants energy hawk moves

7 . This path of energy from one organism to another is called a moves food chain energy cycle. All organisms are part of an energy chain that begins with the Sun. Study Guide: All organisms need energy. A plant gets its energy from the Sun. If a grasshopper eats the plant, the grasshopper gets the energy that was stored in the plant. If a shrew eats the grasshopper, the shrew gets the energy that was stored in the grasshopper s body. If a hawk eats the shrew, the hawk gets energy. In this way, energy moves from the plant to the grasshopper to the shrew and then to the hawk. This path of energy from one organism to another is called a food chain. All organisms are part of an energy chain that begins with the Sun. Illustration: Illustrate the food chain described above. Make sure to include energy arrows. We can trace the source of energy of the hamburger we eat (as carnivores) back to cows (herbivores) that eat grass (producers) for energy. The grass made food (glucose) for cell growth from the process of photosynthesis by using carbon dioxide in the air, water from the soil, and ultimately, energy from sunlight. Not all energy is completely transferred in a food chain or web. Only a small fraction of energy is passed on to the next level in a food chain. So cows, for example, have to eat an enormous amount of grass to get enough energy for life.

8 Key Concept 3: We can predict how changes in an ecosystem can affect the flow of energy in a food web. Changes to an ecosystem, such as a forest fire, can cause animals to leave and some animals and plants to perish, which can have an impact on the flow of energy in a food web. Question: How do changes in an ecosystem affect a food web? Passage: circle your answer choice. Most organisms belong to more than one food chain, which means many food chains are linked together in a food web. Ecosystems not only include nonliving things, but also all the things in a certain area. The organisms in an ecosystem affect plants nonliving living nonliving affect interact floods with one another as well as with their nonliving environment. Ecosystems sometimes change which can affect the organisms in the ecosystem. Fires, droughts, and floods interact plants living are all changes that might damage an ecosystem. These changes can

9 living affect nonliving interact the food webs of the ecosystem. While changes can harm ecosystems, time can sometimes heal them. Study Guide: Most organisms belong to more than one food chain, which means many food chains are linked together in a food web. Ecosystems not only include nonliving things, but also all the living things in a certain area. The organisms in an ecosystem interact with one another as well as with their nonliving environment. Ecosystems sometimes change which can affect the organisms in the ecosystem. Fires, droughts, and floods are all changes that might damage an ecosystem. These changes can affect the food webs of the ecosystem. While changes can harm ecosystems, time can sometimes heal them. Illustration: Illustrate a forest ecosystem before and after a forest fire. Forest fires cause the removal of key plant and animal life that provide crucial food sources for multiple creatures. Just like removing the foundation of a bridge, which causes the whole structure to collapse, removing key organisms in a food web can cause an ecosystem to collapse. Nature exists in a delicate balance where all creatures struggle for survival. When that balance is upset by disease, natural disaster, overpopulation, or human intervention, gaps are created in the local food web, which ultimately lead to a decline in the entire ecosystem.

10 Lab Question: The trees in a deciduous forest environment are both tall and short. The environment where the trees grow is hit by a severe drought, killing most of the tall trees. The following year, there is a normal amount of rain. Which of the following will most likely occur? Answer: The smaller trees will increase in height. Write your If/Then statement: Lab Question: In 2011, fires in Bastrop County, Texas were the most destructive wildfires in Texas history. The fire spread through the Loblolly pine trees and scorched nearly 5,700 acres of Bastrop State Park. The majority of the Houston toad s habitat was lost, and the Lost Pines Forest was heavily affected. A food web of the Bastrop State Park environment is shown below.

11 The loss of habitat for the Houston Toad most likely affected the food web by Answer: causing an increase in the number of insects Write your If/Then statement: Lab Question: A food web diagram is actually a model. It is a representation of what may occur in nature.

12 Which of the following is NOT a limitation of this model? Answer: It contains organisms typically found in a particular ecosystem. Write your If/Then statement: Lab Question: A student conducts an experiment to see how the amount of light a plant receives affects its growth. He gives Plant A two hours of light, Plant B four hours of light, Plant C six hours of light, and Plant D eight hours of light. Which is the most valid conclusion for an investigation on plants and light? Answer: Plants that receive at least six hours of light grow the best. Write your If/Then statement