Unit 3 – Ecological OrganizationsUnit 3 – Ecological Organizations- EcologyEcology – the study of the interactions among – the study of the interactions among

living things, and between living things and their living things, and between living things and their surroundings.surroundings.

- 6 levels of organization:6 levels of organization:1.1. organismorganism – individual living thing – individual living thing

2.2. populationpopulation – group of individuals of the same species – group of individuals of the same species in an area at a certain time.in an area at a certain time.

3.3. communitycommunity – a group of populations in a certain area. – a group of populations in a certain area.

4.4. ecosystemecosystem – all the organisms in an area along with – all the organisms in an area along with non-living factors (climate, water, soil, etc.)non-living factors (climate, water, soil, etc.)

5.5. biomebiome – major regional or global community of – major regional or global community of organismsorganisms

6.6. biospherebiosphere – anywhere on earth where life is found, – anywhere on earth where life is found, from high mountains to deep ocean trenchesfrom high mountains to deep ocean trenches

Biotic and Abiotic FactorsBiotic and Abiotic Factors

Biotic factorsBiotic factors – living things such as – living things such as bacteria, fungus, plants and animalsbacteria, fungus, plants and animals

Abiotic factorsAbiotic factors – non-living things such – non-living things such as moisture, temperature, wind, sunlight as moisture, temperature, wind, sunlight and soil.and soil.

BiodiversityBiodiversity – variety of living things in an – variety of living things in an ecosystemecosystem

Keystone SpeciesKeystone Species – species that has an – species that has an unusually large effect on an ecosystem.unusually large effect on an ecosystem.

Energy in EcosystemsEnergy in EcosystemsProducersProducers : : get their energy from non-living sources (make get their energy from non-living sources (make

their own food), sometimes called their own food), sometimes called autotrophsautotrophs Get their energy either by photosynthesis (from Get their energy either by photosynthesis (from

light) or chemosynthesis (from chemicals)light) or chemosynthesis (from chemicals)

Consumers:Consumers: get their energy by consuming/eating another get their energy by consuming/eating another

living thing (dead or alive), sometimes called living thing (dead or alive), sometimes called heterotrophsheterotrophs..

Questions 1-2, page 400Questions 1-2, page 4001.1. What are the five different levels of What are the five different levels of

organization studied by ecologists?organization studied by ecologists?

- organism, population, community, - organism, population, community, ecosystem, biome.ecosystem, biome.

2.2. Describe the three general methods used by Describe the three general methods used by ecologists to study organisms.ecologists to study organisms.

- Observation is the act of watching something over Observation is the act of watching something over time, such a population of birds. Experimentation time, such a population of birds. Experimentation can occur in the lab or in the field and involves can occur in the lab or in the field and involves testing a hypothesis. Modeling is a computer-testing a hypothesis. Modeling is a computer-based or math-based method used to predict how based or math-based method used to predict how changes in one variable may affect another.changes in one variable may affect another.

Questions 3-4, p400Questions 3-4, p4003.3. What ecological research methods would you use to study bird What ecological research methods would you use to study bird

migration? Explain your choices.migration? Explain your choices.- Observation – band birds and capture them at each end of Observation – band birds and capture them at each end of

their migratory route to record their movement. their migratory route to record their movement. Experimentation – devise an experiment to test the what Experimentation – devise an experiment to test the what triggers migration. Modeling – develop a computer model that triggers migration. Modeling – develop a computer model that includes different variables that might predict the time and includes different variables that might predict the time and path of migration.path of migration.

4.4. How might an ecologist use modeling to study fire in a forest How might an ecologist use modeling to study fire in a forest ecosystem? What might be some key variables used to create ecosystem? What might be some key variables used to create the model?the model?

- Sample answer: Ecologists could use models to determine Sample answer: Ecologists could use models to determine movement of fire, locations where prescribed burns should movement of fire, locations where prescribed burns should take place, and areas with the potential for fire outbreaks. take place, and areas with the potential for fire outbreaks. Key variables might include forest density, types of trees, Key variables might include forest density, types of trees, plant and animals populations, wind patterns, and weather plant and animals populations, wind patterns, and weather conditions.conditions.

Question 5, p400Question 5, p4005.5. Ernst Haeckel was greatly influenced by the Ernst Haeckel was greatly influenced by the

writings of Charles Darwin. How do the principles writings of Charles Darwin. How do the principles of ecology relate to understanding how of ecology relate to understanding how adaptations occur?adaptations occur?

- Species are adapted to their environments. This - Species are adapted to their environments. This concept is directly related to the study of ecology, concept is directly related to the study of ecology, in which the interactions between organisms and in which the interactions between organisms and the environment are studied. By understanding the environment are studied. By understanding the interactions within an ecosystem, scientists the interactions within an ecosystem, scientists can develop an understanding of how populations can develop an understanding of how populations evolve in response to their environments. evolve in response to their environments.

Questions 1-2, p404Questions 1-2, p404

1.1. Select an ecosystem that is familiar to you and Select an ecosystem that is familiar to you and describe the biotic and abiotic factors that exist describe the biotic and abiotic factors that exist there.there.

- Answers should show that students understand that - Answers should show that students understand that biotic factors are living things and abiotic are non-biotic factors are living things and abiotic are non-living.living.

2.2. How would the removal of a keystone species How would the removal of a keystone species affect an ecosystem’s biodiversity?affect an ecosystem’s biodiversity?

- The removal of a keystone species would decrease The removal of a keystone species would decrease the ecosystem’s biodiversity.the ecosystem’s biodiversity.

3.3. Explain how a change in a an abiotic factor Explain how a change in a an abiotic factor such as sunlight would affect biodiversity.such as sunlight would affect biodiversity.

- Changes in amount of sunlight might affect local - Changes in amount of sunlight might affect local temperatures, leading to a change in the numbers temperatures, leading to a change in the numbers and types of species in the ecosystem. New and types of species in the ecosystem. New species may move into the area, taking the place species may move into the area, taking the place of those that cannot survive.of those that cannot survive.

4.4. Human are sometimes described as being a Human are sometimes described as being a keystone species. Does this label fit? Why or keystone species. Does this label fit? Why or Why not?Why not?

- Keystone species are those that help to establish Keystone species are those that help to establish and maintain a complex web of life. Humans do and maintain a complex web of life. Humans do not fit this label because human activities often not fit this label because human activities often decrease, rather than increase biodiversity.decrease, rather than increase biodiversity.

5.5. What role might an abiotic factor such as What role might an abiotic factor such as temperature play in the evolution of a species?temperature play in the evolution of a species?

- A long-term temperature change could result A long-term temperature change could result in selective pressure that selects for in selective pressure that selects for individuals better adapted to the temperature, individuals better adapted to the temperature, causing populations to evolve. It could alter causing populations to evolve. It could alter the types of food available, again creating the types of food available, again creating selective pressure toward individuals that can selective pressure toward individuals that can take advantage of different food sources.take advantage of different food sources.

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Questions 1-3, page 407Questions 1-3, page 4071.1. How does the stability of an ecosystem depend How does the stability of an ecosystem depend

on its producers?on its producers?- Producers bring energy into an ecosystemProducers bring energy into an ecosystem

2.2. What are the two processes used by producers What are the two processes used by producers to obtain energy?to obtain energy?

- Photosynthesis and chemosynthesisPhotosynthesis and chemosynthesis

3.3. Few producers live deep below a lake’s surface. Few producers live deep below a lake’s surface. Suggest an explanation for this pattern.Suggest an explanation for this pattern.

- sunlight cannot penetrate the water to a great - sunlight cannot penetrate the water to a great depth, so photosynthesizing organisms are more depth, so photosynthesizing organisms are more common near the surface.common near the surface.

4.4. Could producers survive without consumers? Could producers survive without consumers? Explain why or why not?Explain why or why not?

- Producers do not require consumers to fill material - Producers do not require consumers to fill material needs as a food source. So in that sense, needs as a food source. So in that sense, producers do not need consumers to survive.producers do not need consumers to survive.

5.5. How might chemosynthetic organisms help How might chemosynthetic organisms help scientists to understand how life developed on scientists to understand how life developed on Earth?Earth?

- Chemosynthetic organisms live in environments that - Chemosynthetic organisms live in environments that may be similar to those that existed on Earth may be similar to those that existed on Earth billions of years ago, when life was beginning to billions of years ago, when life was beginning to develop. Studying these organisms enables develop. Studying these organisms enables scientists to infer how different life forms may have scientists to infer how different life forms may have evolved as Earth changed.evolved as Earth changed.

Questions 1-2, p411Questions 1-2, p411

1.1. Why are food chains especially useful for Why are food chains especially useful for describing the relationships of specialists?describing the relationships of specialists?

- Specialists have specific diets that include only Specialists have specific diets that include only one type of organism, which produces a simple one type of organism, which produces a simple food chain.food chain.

2.2. What happens to energy as it flows through a What happens to energy as it flows through a food web?food web?

- Some energy is stored in the organism (10%), but Some energy is stored in the organism (10%), but much energy is dissipated into the environment much energy is dissipated into the environment (90%).(90%).

3.3. Only a small percentage of all consumers are Only a small percentage of all consumers are specialists. What danger does a specialist specialists. What danger does a specialist faces that a generalist does not?faces that a generalist does not?

- If a specialist’s food source becomes scarce or If a specialist’s food source becomes scarce or disappears, the population may die out. A generalist disappears, the population may die out. A generalist facing the loss of one of its food sources can shift to facing the loss of one of its food sources can shift to a different food source.a different food source.

4.4. How might the stability of an ecosystem be How might the stability of an ecosystem be affected if all the decomposers were suddenly affected if all the decomposers were suddenly removed?removed?

- The stability of the ecosystem would be negatively The stability of the ecosystem would be negatively affected because without decomposers, vital affected because without decomposers, vital nutrients would not be returned into the environment.nutrients would not be returned into the environment.

Question 5Question 55.5. How might an oil spill in the ocean affect an How might an oil spill in the ocean affect an

aquatic food web? What might happen to the aquatic food web? What might happen to the food web on land located near the spill? food web on land located near the spill? Explain your answers.Explain your answers.

- The entire food web would be affected by the oil spill. - The entire food web would be affected by the oil spill. Oily water may kill off phytoplankton. The loss of Oily water may kill off phytoplankton. The loss of smaller fish would affect larger fish, which in turn smaller fish would affect larger fish, which in turn affect tertiary consumers. Plants and animals that affect tertiary consumers. Plants and animals that live along the coast would also be affected as the oil live along the coast would also be affected as the oil seeped onto the shore. The overall effect would be seeped onto the shore. The overall effect would be a decline in the availability of food sources both a decline in the availability of food sources both within and outside the ocean. within and outside the ocean.

Questions 1-3, p416Questions 1-3, p4161.1. How does the hydrological cycle move water through the How does the hydrological cycle move water through the

environment?environment?- Precipitation falls to Earth, and transpiration and Precipitation falls to Earth, and transpiration and

evaporation transfer water back into the atmosphere as evaporation transfer water back into the atmosphere as water vapour.water vapour.

2.2. What are four elements that cycle through ecosystems, and What are four elements that cycle through ecosystems, and why are they important?why are they important?

- oxygen, carbon, nitrogen and phosphorus; they are all - oxygen, carbon, nitrogen and phosphorus; they are all necessary for life on Earth.necessary for life on Earth.

3.3. Why might farmers plant legumes such as peas to improve Why might farmers plant legumes such as peas to improve the nitrogen levels in their soil?the nitrogen levels in their soil?

- Legumes have root nodules, which contain nitrogen-fixing - Legumes have root nodules, which contain nitrogen-fixing bacteria. Increased levels increase the fertility of the soil.bacteria. Increased levels increase the fertility of the soil.

4.4. Explain the importance of decomposers to the Explain the importance of decomposers to the overall biogeochemical cycle.overall biogeochemical cycle.

- Decomposers break down organisms and release Decomposers break down organisms and release various elements, including nitrogen and various elements, including nitrogen and phosphorus, which other organisms can then use.phosphorus, which other organisms can then use.

5.5. How might Earth’s biogeochemical cycles help How might Earth’s biogeochemical cycles help scientists to understand the early history of life scientists to understand the early history of life on Earth?on Earth?

- Studies of the biogeochemical cycles and how they - Studies of the biogeochemical cycles and how they interact may help scientists reconstruct the interact may help scientists reconstruct the sequence of events that led to changes at Earth’s sequence of events that led to changes at Earth’s surface that would enable different types of surface that would enable different types of organisms to evolve.organisms to evolve.

Questions 1-3, p419Questions 1-3, p4191.1. How does an energy pyramid help to describe How does an energy pyramid help to describe

energy flow in a food web?energy flow in a food web?- An energy pyramid shows the relative contribution An energy pyramid shows the relative contribution

to energy flow made by each trophic level in an to energy flow made by each trophic level in an ecosystem.ecosystem.

2.2. What is the difference between a biomass What is the difference between a biomass pyramid and a pyramid of numbers?pyramid and a pyramid of numbers?

- A biomass pyramid compares the mass of A biomass pyramid compares the mass of organisms that make up each trophic level in an organisms that make up each trophic level in an ecosystem; a pyramid of numbers compares the ecosystem; a pyramid of numbers compares the number of individual organisms that make up each number of individual organisms that make up each trophic level.trophic level.

3.3. How would you draw a pyramid of numbers for How would you draw a pyramid of numbers for a dog with fleas? What shape would it take?a dog with fleas? What shape would it take?

- The bottom level would be the dog, and the fleas - The bottom level would be the dog, and the fleas would be the top level. This would be an inverted would be the top level. This would be an inverted pyramid because there are many fleas to just one pyramid because there are many fleas to just one dog.dog.

4.4. If each level in a food chain typically loses 90 If each level in a food chain typically loses 90 percent of the energy it takes in, and the percent of the energy it takes in, and the producer level uses 1000 kcal of energy, how producer level uses 1000 kcal of energy, how much energy is left after the third trophic level?much energy is left after the third trophic level?

- The first trophic level uses 1000 kcal; the second The first trophic level uses 1000 kcal; the second trophic level uses 100 kcal; the third trophic level trophic level uses 100 kcal; the third trophic level uses 10 kcal, leaving 1 kcaluses 10 kcal, leaving 1 kcal

Question 5, p419Question 5, p419

5.5. Why is a herbivorous diet more energy Why is a herbivorous diet more energy efficient than a carnivorous diet? Explain efficient than a carnivorous diet? Explain your answer.your answer.

- a herbivorous diet is more energy a herbivorous diet is more energy efficient because it is the closest trophic efficient because it is the closest trophic level to producers, meaning there is more level to producers, meaning there is more available energy to use.available energy to use.