Module 7 : Ecosystem and the Environment

Question 0

(Organisms and the Environment Part 1 : Abiotic and Biotic Factors)
What are abiotic and biotic factors?

Answer 0

• abiotic factors : an organisms environment included nonliving, or abiotic features, such as temperature, sunlight, precipitation, rocks, ponds
• biotic factors : living organisms

Question 1

(Organisms and the Environment Part 1 : Abiotic and Biotic Factors)
Give examples of ecological studies performed at the population, community, and ecosystem level.

Answer 1

• population : group of individuals of a single species that occupies a given area; studies focus on size and how it changes with time
• community : consists of all organisms that live within a given area; studies focus on interactions between species
• ecosystem : the level in which scientists study both the biotic and abiotic components of the environment (the flow of energy, cycling of chemicals)

Question 2

(Organisms and the Environment Part 1 : Abiotic and Biotic Factors)
Which of the following are types of abiotic components of an ecosystem? (Select all that apply)
(A) seeds used as food sources
(B) soil mineral levels
(C) hours of sunlight
(D) lichens

Answer 2

ANSWER(S)
(B) soil mineral levels
(C) hours of sunlight

Question 3

(Organisms and the Environment Part 1 : Abiotic and Biotic Factors)
An ecologist is interested in studying how the number of mountain lions in a certain park has changed over the last decade. What type of ecological study is this?
(A) individual
(B) population
(C) community
(D) ecosystem

Answer 3

ANSWER

(B) population

Question 4

(Organisms and the Environment Part 2 : Species Interactions)
What are examples of competition in ecosystems?

Answer 4

• trees growing taller and taller to compete for sunlight
• animals hunting the same prey
• predators fighting over a kill
• anytime two species in a community use the same resource, that is in limited supply

Question 5

(Organisms and the Environment Part 2 : Species Interactions)
What components are included in a species’ niche?

Answer 5

• the total set of biotic (living) and abiotic (non living) resources a species uses within a community
• food eaten, water drunk, space occupied, etc. defines a species role within a community

Question 6

(Organisms and the Environment Part 2 : Species Interactions)
What is symbiosis? What are 3 different kinds of symbiosis?

Answer 6

• close relationship between two species that benefits at least one of the species
  (1) commensalism
  (2) parasitism
  (3) mutualism

Question 7

(Organisms and the Environment Part 2 : Species Interactions)
Give examples of : 
(A) commensalism
(B) parasitism
(C) mutualism

Answer 7

(A) commensalism : a remora hitched a ride on a shark, the remora obtains protection from its hosts and feeds on leftover scraps from the Sharks meals.
(B) parasitism : fleas, tapeworms, and other organisms that live in or in their hosts and obtain nutrients from them
(C) mutualism : fungus receives nutrients from the plant while helping the roots to absorb water and minerals

Question 8

(Organisms and the Environment Part 2 : Species Interactions)
Which if the following is an example of mutualism?
(A) Fleas biting a dog
(B) Mushrooms pairing with tree roots to exchange water and nutrients
(C) A hawk and a snake fighting over a mouse
(D) A mother lion giving up her food for her babies

Answer 8

ANSWER

(B) Mushrooms pairing with tree roots to exchange water and nutrients.

Question 9

(Organisms and the Environment Part 2 : Species Interactions)
What discovery was made that showed the warblers followed the competitive exclusion principle?
(A) The warblers were competing for the exact same resources, but excluding other bird species.
(B) The warblers were actually specialized for certain parts of the tree, so their niches differed.
(C) One species of warbler was the best competitor, so all the other species went extinct.
(D) The warblers did not follow the competitive exclusion principle.

Answer 9

ANSWER

(B) The warblers were actually specialized for certain parts of the tree, so their niches differed.

Question 10

(Organisms and the Environment Part 3 : Biomes)

What is a biome?

Answer 10

• different regions which support various kinds of life (e.g. Forest, grassland, desert, and tundra)

Question 11

(Organisms and the Environment Part 3 : Biomes)

Describe general characteristics of freshwater and saltwater biomes.

Answer 11

• freshwater biomes :
  
  • includes lakes and ponds, rivers, streams, springs, and wetlands
  • abiotic factors : speed of the water, climate, amount of sunlight
  • biotic factors : contain about 12% of world’s known animals, 40% of the world’s fish species, many types of plants
• saltwater biomes :
  
  • oceans
  • abiotic factors : salinity, depth, light, and temperature
  • biotic factors : seaweed, fish, mammals, bacteria, plankton

Question 12

(Organisms and the Environment Part 3 : Biomes)
Which of the following is NOT a characteristic of the tundra biome?
(A) lichens
(B) reindeer
(C) permafrost
(D) high biodiversity

Answer 12

ANSWER

(D) high biodiversity

Question 13

(Organisms and the Environment Part 4 : Ecological Succession)
What is ecological succession?

Answer 13

• gradual process by which ecosystems change and develop over time

Question 14

(Organisms and the Environment Part 4 : Ecological Succession)
How does primary ecological succession differ from secondary ecological succession?

Answer 14

• primary ecological succession : gradual establishment of biotic communities in lifeless areas where there is no soil in a terrestrial ecosystem or no bottom sediment in an aquatic one
• secondary ecological succession : development of communities in an area in which vegetation has been removed or destroyed, but the soil is not destroyed

Question 15

(Organisms and the Environment Part 4 : Ecological Succession)
What is the intermediate disturbance hypothesis? What effect do regular moderate disturbances have on ecosystems?

Answer 15

• as long as they aren’t too extreme, the can contribute to biodiversity
• this is true because different species make use of different habitats and periodic disturbances guarantee there will always be habitat at varying stages of recovery

Question 16

(Cycles and Energy Flow Part 1 : Food Chains and Food Webs)
Identify the following : 
(A) producers
(B) autotrophs
(C) consumers
(D) primary consumers
(E) secondary consumers
(F) tertiary consumers
(G) heterotrophs

Answer 16

(A) producers :
- organisms that use the Sun’s energy to make their own food (all plants)
(B) autotrophs :
- organism that makes its own food and sustains itself without eating other organisms
(C) consumers :
- organism that obtains energy and nutrients by feeding on other organisms or their remains
(D) primary consumers :
- an herbivore
- an organism in the trophic level of an ecosystem that eats plants or algae
(E) secondary consumers :
- a member of the tropic level of an ecosystem consisting of carnivores that eat herbivores
(F) tertiary consumers :
- an organism that eats secondary consumers; other carnivores
(G) heterotrophs :
- organism that gets its energy (organic food molecules) by consuming other organisms

Question 17

(Cycles and Energy Flow Part 1 : Food Chains and Food Webs)
Define the following terms : 
(A) decomposers
(B) herbivores
(C) carnivores
(D) omnivores

Answer 17

(A) decomposers : 
  - bacteria that break down nutrients in dead matter into simple pure substances
(B) herbivores : 
  - an organism that eats only plants
(C) carnivores : 
  - a flesh-eating animal
(D) omnivores : 
  - an organism that eats both plants and animals

Question 18

(Cycles and Energy Flow Part 1 : Food Chains and Food Webs)

Explain the transfer of energy from the Sun through the food chain.

Answer 18

• Sun’s energy reaches plants, which use photosynthesis to create organic matter (biomass)
• primary consumers eat the plants
• secondary consumers eat the primary consumers, etc.

Question 19

(Cycles and Energy Flow Part 1 : Food Chains and Food Webs)
Where would hummingbirds appear on the food chain?
(A) producers
(B) primary consumers
(C) secondary consumers
(D) decomposers

Answer 19

ANSWER

(B) primary consumers

Question 20

(Cycles and Energy Flow Part 1 : Food Chains and Food Webs)
Which of the following is not an autotroph?
(A) photosynthetic algae
(B) producer
(C) mushroom
(D) plant

Answer 20

ANSWER

(C) mushroom

Question 21

(Cycles and Energy Flow Part 2 : Trophic Levels)

Describe how organisms use the energy contained in their food supply

Answer 21

• producers receive energy from the Sun, creating their own energy-rich molecules and food
• consumers gain their energy by eating producers or other consumers; they use the energy to build biomass, feces, and maintenance (energy required to live on)

Question 22

(Cycles and Energy Flow Part 2 : Trophic Levels)

What happens to energy as it moves from the first trophic level to the second and third trophic levels?

Answer 22

• energy is lost as you go up the food chain
• approximately 10% is available from one level to the next
• because not every organism at each trophic level is consumed by the next level, when a consumer eats energy goes to other tasks than just creating biomass - specifically feces (organic material unable to digest) and maintenance (energy consumer requires to live : finding food, run, mate, breathe, etc.)
• these activities also cause energy to be lost to the environment as heat

Question 23

(Cycles and Energy Flow Part 2 : Trophic Levels)

How much energy is transferred between trophic levels?

Answer 23

• only 10%

- energy is used up as feces, for maintenance, and growth and reproduction

Question 24

(Cycles and Energy Flow Part 2 : Trophic Levels)

Why is energy lost to the environment during respiration?

Answer 24

• because when energy is transformed from one form to another, energy gets lost to the environment as heat
• every chemical reaction involves some energy loss to the environment

Question 25

(Cycles and Energy Flow Part 2 : Trophic Levels)
Describe an example food chain, with at least four trophic levels. What happens if one of the organisms in the food chain is removed from the ecosystem? Predict what effect that would have on the other organisms.

Answer 25

• Producers :
  
  • entire food system shuts down because there is no food for consumers, all life comes to a halt
• Primary consumers :
  
  • secondary consumers have two options either become extinct or become the primary consumer
  • abundance of tertiary consumers
• Secondary consumers :
  
  • there would be an abundance of primary consumers because secondary consumers aren’t there to consume them
• Tertiary consumers :
  
  • populations of primary consumers and secondary consumers would explode which could lead to degradation of habitat

Question 26

(Cycles and Energy Flow Part 2 : Trophic Levels)
In an energy pyramid, there is less energy at the top of the pyramid because :
(A) not all organisms at one trophic level are eaten by organisms at the next trophic level.
(B) energy is lost to the environment as heat.
(C) maintenance and producing feces use a lot of the energy an organism takes in.
(D) all of the above.

Answer 26

ANSWER

(D) all of the above

Question 27

(Cycles and Energy Flow Part 3 : Nutrient Cycles)

What is the difference between organic and inorganic compounds?

Answer 27

• organic compounds :
  
  • any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon
• inorganic compounds :
  
  • does not contain carbon

Question 28

Quiz A

What statement correctly describes an interaction between the abiotic and biotic components of a temperate forest?

Answer 28

• The cold temperatures during winter months result in trees losing their leaves, many mammals go into hibernation, and most birds migrate south to warmer climates.
• Temperate forests have four season, including a warm summer and a cold winter. Temperatures average approximately 0 degrees Celsius and 30 degrees Celsius. The biotic species in the ecosystem adapt to the cold winter by losing leaves, hibernating, and migrating.

Question 29

Quiz A

What is an examples of adaptations of organisms to the cold winter months in a coniferous forest?

Answer 29

• The shape and waxy layer of pine needles helps prevent freezing.
• Conifer trees such as spruce and fir trees have pine needles which are well adapted for the cold climate. The cone-shape of conifer trees also allows snow to fall off so it does jot accumulate and break the branches.

Question 30

Quiz A

What statement is an example of commensalism?

Answer 30

• A remora rides on a shark and feeds on its leftovers.
• Commensalism is a type of symbiotic relationship that occurs when one organism benefits and the other organism is not affected. A remora does not affect the shark but benefits by eating the scraps that the shark does not eat.

Question 31

Quiz A

What correctly defines a niche?

Answer 31

• All of the abiotic and biotic resources used by a species.
• A niche describes the abiotic and biotic resources that a species uses and includes the organisms it eats, the space it inhabits, as well as the water it drinks.

Question 32

Quiz A

What statement correctly describes primary ecological succession?

Answer 32

• Hardy pioneer species that can withstand changes in temperature and limited nutrients grow first.
• Primary succession occurs when rock is formed or exposed through volcanic or glacial activity. The lack of soil in the ecosystem requires that the pioneer species are able to grow on rock without the shelter of other species.

Question 33

Quiz A

What correctly describes how solar energy affects the Earth’s surface?

Answer 33

• The Northern Hemisphere is warmer during the summer months because its angle to the Sun results in more direct solar energy.
• Solar energy affects the Earth’s surface in many ways. Summer in the Northern Hemisphere occurs when the Earth is angled towards the Sun and receives more direct solar energy.

Question 34

Quiz A

What statement correctly describes the role of bacteria in the nitrogen cycle?

Answer 34

• Nitrogen-fixing bacteria convert atmospheric nitrogen (N2) into ammonium (NH4+).
• Bacteria are essential to the nitrogen cycle and convert inorganic atmospheric nitrogen molecules into organic molecules that can be used by animals. Nitrogen-fixing bacteria start the process by taking atmospheric nitrogen and converting it to ammonium which is then converted to nitrates by nitrifying bacteria. Denitrifying bacteria return convert organic nitrogen into inorganic nitrogen so it can be released into the atmosphere.

Question 35

Quiz A

What processes of the hydrologic (water) cycle require an input of solar energy?

Answer 35

• Evaporation and wind
• Solar energy warms the Earth’s surface and causes evaporation of water into the atmosphere. Winds are caused when air moves from warm areas, heated by solar radiation, to cold areas.

Question 36

Quiz A

What describes the difference between autotrophs and heterotrophs?

Answer 36

• Autotrophs generate the glucose they need by converting inorganic molecules into organic molecules; heterotrophs must consume other organisms to obtain the glucose they need.
• Autotroph (“self-feeders”) is a term used for organisms that are producers, such as plants, that can make their own food via the process of photosynthesis. These organisms use the sun’s energy to convert the inorganic molecules carbon dioxide and water into the organic molecule glucose with water as a by-product. Heterotrophs (“other-feeders”) must consume food outside food sources for energy. Examples of heterotrophs include : humans, snakes, dogs, mice, horses, butterflies, turtles, etc.

Question 37

Quiz A

Why is only 10% of energy transferred between trophic levels in an energy pyramid?

Answer 37

• Most of the energy is used directly by the organism for breathing, finding food, and mating.
• The organisms at each trophic level use most of the energy for maintenance (breathing, finding food, repairing injuries), reproduction, and growth. Some energy is also lost to the environment as heat leaving only 10% of the energy available up to the next trophic level.

Question 38

Quiz B

What statement correctly describe an interaction that exists between abiotic and biotic factors in temperate grasslands?

Answer 38

• Periodic droughts and fire discourages the growth of trees, and foster an abundance of grasses.
• Droughts and fire are abiotic factors that affect the biotic factors in the temperate grassland biome. Grasses quickly repopulate the ecosystem after a fire whereas tree growth is limited.

Question 39

Quiz B

What statement correctly describes how the permafrost layer affects the tundra biome?

Answer 39

• It favors the growth of low shrubs and lichens because they do not require a deep root system.
• Permafrost is a permanent layer of frozen subsoil which prevents the growth of many species. The plant species in the tundra include low shrubs, moss, and grasses, and lichen are also common.

Question 40

Quiz B

What statement correctly describes a mutualistic relationship between organisms?

Answer 40

• Honey bees mediating pollination of flowers while eating nectar.
• This is an example of mutualism, where both organisms involved benefit from the relationship. The bee is able to acquire energy from eating the nectar and the flowers benefit from having their pollen distributed over a large area with more precision than other pollen distribution methods.

Question 41

Quiz B

What are parts of a deers’ niche?

Answer 41

• Grass, shrubs, and water
• A niche is a total set of abiotic (non living) and biotic (living) resources used by an organism. Deer are herbivores (plant eaters) and will consume the biotic factors of grass and plant shrubs as part of their diet, and of course require the abiotic factor of water to sustain life.

Question 42

Quiz B

What disturbances would most likely be followed by secondary succession?

Answer 42

• Fire on a prairie consumes existing biotic species.
• Secondary succession occurs in areas that have been distributed by a fire or other event but the soil remains intact for colonization by biotic species like grasses.

Question 43

Quiz B

What is the relationship between solar energy and photosynthesis?

Answer 43

• During photosynthesis, solar energy is used to convert carbon dioxide into oxygen and glucose.
• Solar energy is used in the light-dependent reaction of photosynthesis. During this reaction, solar energy excites chlorophyll, ejecting an electron. Oxygen becomes a by-product as the chlorophyll uses an electron from water to replace the missing electron.

Question 44

Quiz B

What correctly describes part of the carbon cycle?

Answer 44

• Carbon dioxide from the atmosphere is absorbed during photosynthesis and then returned to the atmosphere during cellular respiration.
• Photosynthetic organisms convert atmospheric carbon dioxide into glucose. Organisms release carbon dioxide into the atmosphere when they break down glucose through cellular respiration. Both of these processes are parts of the carbon cycle.

Question 45

Quiz B

What is a pair of processes that is part of the carbon cycle?

Answer 45

• Volcanic eruption and burning of fossil fuels

- Carbon dioxide is released into the atmosphere when fossil fuels are burned or when a volcano erupts.

Question 46

Quiz B
In a terrestrial food chain, rabbits ingest plants, snakes ingest rabbits, and Hawks ingest snakes. What term correctly identifies the role of snakes in this food chain?

Answer 46

• Secondary consumer
• In this terrestrial food chain, plants are the producers, rabbits are the primary consumers, snakes are the secondary consumers, and Hawks are the tertiary consumers.

Question 47

Quiz B

What statement correctly describes the energy available at the various trophic levels?

Answer 47

• Few tertiary consumers exist in an ecosystem because the amount of usable energy decreases moving from one trophic level to next.
• The base of the energy pyramid is the first trophic level and consists of producers that carry out photosynthesis. The first trophic level contains most of the energy. At each trophic level, only 10% of energy is transferred to the next level. As a result, there is less energy available to support tertiary consumers resulting in fewer of these organisms.

Question 48

(Cycles and Energy Flow Part 2 : Trophic Levels)
Every chemical reaction involves :
(A) maintaining body systems
(B) losing energy to the environment
(C) the destruction of a small amount of matter
(D) all of the above

Answer 48

ANSWER

(B) losing energy to the environment