Chapter 38pg 825-842

End of the Chapter Book Questions

Level 2Level 3Level 4

Level 2 Questions

#’s 2, 4, 7, 9, 11, 12, 14, 16

Distinguish between

ecosystem, community, population #2• Ecosystem – consists of all populations in

an ecological community together with the physical environment (flow of energy; recycling of materials)

• Population – group of animals that coexist with others of the same species forming reproductive communities

• Community – a group of populations that exist in nature

#4• Define niche:

• How does the “realized” niche differ from its “fundamental” niche?

Ecological Role – including all interactions, habitat, feeding behavior, mating, competition, and other interactions with organisms

“realized” niche – where an organism actually lives, what it eat and does

“fundamental” niche – its potential, what it could do with no competition and plenty of resources

#4• How does a niche differ from a guild?

Guilds – niche / resource partitioning – where a resource is shared.

Two birds eat the same seed to reduce competition one eats the smaller seeds and the other eats the larger seeds.

Contrast Exponential growth and logistic growthUnder what conditions might you expect a population to exhibit the growthWhy can’t exponential be indefinite? #7

• Exponential (r) – intrinsic rate of increase; steep rising curve

• Logistic (sigmoid) – occurs when population density exerts a negative feedback on growth rate

• Cant be indefinite growth because resources soon run out.

#9• Herbivory is an example of an interspecific interaction beneficial for the animal (+) but harmful to the plant (-).

• What are some (+-) interactions among animal populations?Predation (+ - ) Parasitism ( + - )

Predation is short-term, eat and move on.

Parasitism is long-term, live off the host

#9• Continued: • What is the differences between

commensalism and mutualism?

Commensalism: ( + o ) Mutualism: ( + + )

#11• Define: Predation• How does predator-prey relationships

differ from parasite-host relationship?

Predation: is when one organism feeds off of another, it can be short term- one animal kills another.

Parasitism is a special symbiotic form of predation, where an organisms feeds off of and lives on a host organism. Usually (not always) the parasite does not kill its host.

#11• Continued:• Why is the evolutionary race between

predator and prey one that the predator cannot afford to win?

Predator must win – in order to obtain food / energy

#12• Mimicry of monarch butterflies by viceroys

is an example of a palatable species resembling a toxic one.

• What is the advantage to the viceroy of this form of mimicry?

Batesian mimicry: by appearing to be like a noxious (bad smell/taste), the mimic is less likely to be eten by predators who have had a bad experience eating the toxic one.

#12• Continued:• What is the advantage to a toxic species

of mimicking another toxic species?

Muellarian: two unrelated but toxic species look alike and both benefit and heighten the impact of predators avoiding them, because they will more likely have a bad experience.

#14• What is a trophic level and how does it relate to a food chain?

Trophic level: Energy level

Based on how an organism gets its food or energy.

A food chain can show what energy level an organism feeds at.

What is a food chain and how does it differ #16 from a food web?

• Food chain – linking of trophic levels that denote the movement of energy

• Food web – connection of 2 or more chains showing pathways of energy and materials through an ecosystem

Level 3

#’s 1, 8, 10

Term ecology is derived from Greek #1 meaning “house” However as used by scientists the term ecology is not the same as env. How do these 2 terms differ

• Ecology is more than the organisms surroundings; it incorporates behavior, physiology, genetics, and evolution.

• Ecology understands how the interactions work

• Environment – is the surroundings

#8• Growth of a population can be controlled by either density-dependent or density independent mechanisms.

• Define and contrast each.Density Dependent Factors: usually biotic factors such as predation, competition, that impact population growth, especially when the population gets larger, more dense, and nearer to carrying capacity.Density Independent Factors: usually abiotic factors such as hurricanes, floods, fire that impact populations regardless of size

#8• Continued:• Offer examples of how growth of the

human population might be curbed by either agent.Density Dependent Factors: War, Famine, Disease

Density Independent Factors: Massive hot or cold times

#10• Explain how character displacement can ease competition between coexisting species

Character displacement: sharing a resource by using different parts of the resource.

Living in different parts of the tree, eating at different times of the day

Level 4

#’s 13, 17, 19

A keystone species is one whose removal #13 from a community causes extinction of others species. How does the extinction happen?

• Keystone species – a population that influences another population to the point its absence drastically changes the community By reducing competition keystone species may allow more species to coexist.

• Ex: sea star were removed from an area and the mussel population now had no predator and grew exponentially wiping out 25 invertebrate species

#17• How is it possible to have an inverted

pyramid of biomass in which the consumers have a greater biomass than the producers?

Inverted pyramid of biomass: in aquatic systems where algae has a short life span and can tolerate heavy exploitation and grazing, the zooplankton that feed on them will actually have a higher biomass at a given time of year.

#17• Continued: • Can you think of an example of an

inverted pyramid of numbers in which there are, for example, more herbivores than plants on which they feed?Pyramid of numbers: an oak tree (one producer) can hold hundreds to thousands of insects and several mammals

Animal communities surrounding deep-sea #19 vents exist independent of solar energy – How?

• The producers are chemoautotrophic bacteria that derive energy from oxidation of hydrogen sulfide that is abundant in the vent water and carbon dioxide into organic carbon.

#18• The pyramid of energy has been offered

as an example of the second law of thermodynamics. Why?

This is so because at each higher level there is less energy available to use for the next organism. Only 10% moves to the next level, the remainder is lost through biological processes (mainly cell respiration and is transformed into heat energy that ultimately will dissipate in the great beyond.