Producers or Autotrophs: Consumers or Heterotrophs: Decomposers or Heterotrophs:

Transcription

1 Name Date Period All About Ecology Answer the following questions: 1. What is Ecology? 2. What does the Biosphere contain? 3. All living things depend on two main factors for their survival. Name, describe and give examples of each. A. B. 4. Ecology is the study of organisms and their relationships with the biotic as well as the abiotic factors: Define each of the following levels and give an example: A. Organisms: B. Population C. Communities D. Ecosystems E. Biosphere Refer to Chapter 41 to answer the following questions. All living things require energy to survive. How they get this energy is referred to as the feeding relationships in the Ecosystem Define and give examples of each of the following: Producers or Autotrophs: Consumers or Heterotrophs: Decomposers or Heterotrophs: Herbivores: Omnivore: Producers get their energy from the. 1

2 Energy flows through the ecosystem in ONE DIRECTION. It flows from the sun or inorganic compounds to the producers. The consumers then eat the producers. A food chain is a sequence of who eats whom. It is a series of steps that show the transfer of energy from one level (called trophic level) to the next. The arrows denote the direction of energy flow. For example the energy flows from the algae to the mosquito larva as it eats the algae. Therefore the arrow is directed from the algae to the mosquito larvae. 1. All food chains start with which type of living thing? 2. The first organism in each food chain must always be what type of organism? 3. Where do chemosynthetic bacteria get their energy? 4. Herbivores are also called 5. The animals that feed on the herbivores are also called? 6. Secondary consumers are eaten by larger 7. consumers eat the secondary consumers. 8. Give an example of a food chain consisting of one producer and 3 consumers. 2

3 FOOD WEBS: Interconnected food chains. 1. What is used to indicate the flow of energy in a food chain or food web? 2. What is a food web? 3. Write 2 different food chains from the diagram above. Food Chain 1 Food Chain 2 4. Were there any organism/s that was common to both of the food chains? Which ones? 3

4 Trophic Levels: The trophic level of an organism is the position it holds in a food chain. 1. Producers - First trophic level 2. Primary consumers are in the second trophic level 3. Secondary consumers eat primary consumers. They are in the third trophic level 4. Tertiary consumers are in the fourth trophic level. 5. Quaternary consumers are the fifth trophic level 6. Food chains "end" with top predators, animals that have little or no natural enemies. When any organism dies, it is eventually eaten by scavengers/detrivores (like vultures, worms and crabs) and broken down by decomposers (mostly bacteria and fungi), and the exchange of energy continues. Some organisms' position in the food chain can vary as their diet differs. For example, when a bear eats berries, the bear is functioning as a primary consumer. When a bear eats a planteating rodent, the bear is functioning as a secondary consumer. When the bear eats salmon, the bear is functioning as a tertiary consumer (this is because salmon is a secondary consumer, since salmon eat herring that eat zooplankton that eat phytoplankton, that make their own energy from sunlight). Think about how people's place in the food chain varies - often within a single meal! Use the Food web from page 3 to place each organism in the correct trophic level. Three of the organisms have been done for you. First trophic level Second Trophic level Third trophic level Fourth Trophic level Fifth trophic level Robin X X X Bug X Ladybug X 1. The 1 st trophic level consists of consumers called. 2. Name the 2 nd trophic level (both names). 3. Secondary consumers may be eating meat or that eat both plants and animals. 4. What is the 3 rd trophic level called? 5. What is the 4 th trophic level called? 6. At the 5 th trophic level would be consumers that eat consumers. 4

5 Energy Flows through the Ecosystem: Energy from the sun is used by autotrophs and converted to energy in the chemical bonds of organic compounds Ex. Sugars. This allows the plant to grow (increase in mass) and reproduce (increase in numbers). Heterotrophs then eat the autotrophs, use the energy in the organic food in order to survive, grow and reproduce. However, when energy is changed from one form to another, much of that energy is lost and cannot be used for useful work in the next level. Additionally some energy remains at each level. When a caterpillar eats a leaf 50% of the energy stored in the leaf passes out of the body as waste and/or heat 40% is used for the caterpillar to survive Only 10% is used to increase the size of the caterpillar So when the robin eats the caterpillar, it is getting only 10% of the caterpillar This applies to not only energy but also biomass (mass of the living thing) and numbers. 10% Rule states that only 10% of energy, biomass and numbers are available as you go up each trophic level. This is often represented pictorially in a pyramid. The three pyramids are essentially similar. 5

6 Pyramids of Energy Every time an organism eats, it obtains energy from its food So energy is transferred from the 1 st trophic level to the 2 nd trophic level to the 3 rd trophic level and so on. Some of this energy is lost along the way during an organism s metabolism and as heat This energy can be measured in kilocalories (kcal) Energy pyramid: picture showing how much energy is transferred to the different trophic levels in a food chain Pyramid of Energy 10 kcal/m 2 /ye ar 100 kcal/m 2 /year 1000 kcal/m 2 /year 10,000 kcal/m 2 /year Place the organisms from the food web shown on page 3 in the energy/biomass/numbers pyramid below. 6

7 1. In the pyramid of energy, which trophic level contains highest amount of energy?, numbers, biomass. 2. There are many more then there are secondary consumers. 3. What does the shape of the energy pyramid suggest? 4. An ecosystem cannot have more than 4-5 trophic levels. Why? 5. When you eat lettuce you are a 6. When you eat a chicken that has eaten a bug that has eaten the lettuce, you are a? 7. In this ecosystem, the energy in the leaves (producers) is calculated to be 100, 000 kcal. How much of that energy are you getting when you eat the lettuce? chicken?, 8. How much energy is the chicken getting when it eats the bug? Survival and Interaction between and within populations Habitat: The place where an organism lives out its life Niche: all the strategies and adaptations a species uses in its environment o Includes all its interactions with the biotic and abiotic parts of the environment o Each type of organism occupies its own niche to avoid competition with other types of organisms Two species can share the same habitat but not the same niche o Example: Ants and bacteria both live in the dirt (habitat) but have different niches. Ants eat dead insects and bacteria eat dead leaves, dead logs, and animal waste. So ants and bacteria don t compete for resources. Survival Relationships Predator-prey: predators are consumers that hunt and eat other organisms called prey Symbiosis: relationship in which one species lives on, in, or near another species and affects its survival There are 3 types of symbiosis 1. Mutualism: type of symbiosis in which both species benefit Ants living in the tropical acacia trees- trees are protected when ants attack animals that try to feed on the tree and ants receive nectar and shelter from the tree. 7

8 2. Commensalism: type of symbiosis in which one species benefits and the other species is neither harmed nor benefited Spanish moss grows on the branches of trees. The moss gets a habitat and the tree gets nothing. 3. Parasitism: type of symbiosis in which one species benefits and the other species is harmed Parasite: organism that harms but does not kill another organism Host: organism that is harmed by a parasite Ticks feed on dogs, people, etc. The ticks get food (blood) and the hosts lose blood and can be infected with disease. For each of the statements below, state if True or False A habitat is the role a species plays in a community. Habitats may change. A niche is the place where an organism lives its life. A habitat can include only one niche. A species niche includes how the species meets its needs for food and shelter. The centipedes and worms that live under a certain log occupy the same habitat but have different niches. It is an advantage for two species to share the same niche. Competition between two species is reduced when the species have different niches. Biological Magnification: (Look up page 736 in the text) What is biological magnification? Give an example from you reading. 8

9 Cycles in Nature There is only a limited amount of resources (water, oxygen, nitrogen, carbon) on the earth In order to keep these resources available to organisms, they must be recycled after they are used Cycle: a process that recycles a resource so that you end up with what you started with 1. Follow a raindrop through two possible paths through the water cycle, ending as water vapor in the atmosphere. Path 1 Path 2 9

10 Answer the following questions: 2. Describe the role of producers in carbon cycle and oxygen cycle 3. Describe the role of producers in oxygen cycle. 4. Explain how carbon enters the living system and how it leaves. 5. Indicate the role of microorganisms in the cycle, and identify the reservoir for carbon. 7. Explain how photosynthesis and cellular respiration is involved in cycling of oxygen and carbon. 10

11 8. Which organisms can use nitrogen directly from the atmosphere? 9. How does nitrogen return to the atmosphere? 10. It is said that bacteria is the anchor of the ecosystem. Give two reasons why we cannot survive without bacteria? 11. You are one of the six people chosen to live on a self-contained space station. What organisms would you take with you? Describe the functions you will need each organism to perform so you can live there for the next three years when the space shuttle will come for you. 11

12 Population Biology: Chapter 39 Population size of a species is dependent on a number of factors. What are some factors that affect population size of a species? 1. Explain what is happening to the population in the exponential growth graph? 2. How does the exponential population graph differ from the logistic growth graph? 3. Which of the two represent a more realistic population growth curve? 4. Which of these represent the growth curve the human population? 5. Carrying capacity of a population is the maximum number of individuals the environment can support at any given time. What are some reasons that would limit the population size? 12

13 Explain the fluctuations in the phase B of the graph. (p ) Factors effecting population growth a. Density dependent factor Examples of density dependent factors b. Density independent factors Examples of density independent factor c. Competition: i. Interspecific competition: Competition with other species Ex wolves with coyotes ii. Intraspecific competition: Competition within the species. Ex Wolves with wolves 13

14 Deer: Predation or Starvation Introduction: In 1970 the deer population of an island forest reserve about 518 square kilometers in size was about 2000 animals. Although the island had excellent vegetation for feeding, the food supply obviously had limits. Thus the forest management personnel feared that overgrazing might lead to mass starvation. Since the area was too remote for hunters, the wildlife service decided to bring in natural predators to control the deer population. It was hoped that natural predation would keep the deer population from becoming too large and also increase the deer quality (or health), as predators often eliminate the weaker members of the herd. In 1971, ten wolves were flown into the island. Procedure: The results of this program are shown in the following table. The Population Change is the number of deer born minus the number of deer that died during that year. Fill out the last column for each year (the first has been calculated for you). A B C D E F G Year Wolf Population Deer Population Deer Offspring Predation Starvation Deer Population Change , , ,500 1, , , , , , , ,

15 Graph the deer and wolf populations (column B and C) on the graph below. Use one color to show deer populations and another color to show wolf populations. 1. Describe what happened to the deer and wolf populations between 1971 and What do you think would have happened to the deer on the island had wolves NOT been introduced? 3. Most biology textbooks describe that predators and prey exist in a balance. Some scientists have criticized this balance of nature hypothesis because it suggests a relationship between predators and prey that is good and necessary. Opponents of this hypothesis propose the following questions: Why is death by predators more natural or "right" then death by starvation? How does one determine when an ecosystem is in "balance"? Do predators really kill only the old and sick prey? What evidence is there for this statement? What is your opinion of the balance of nature hypothesis? Would the deer on the island be better off, worse off, or about the same without the wolves? Defend your position. 15