Transcript ch 38 Ecology Review Questions

Chapter 38
pg 825-842
End of the Chapter
Book Questions
Level 2
Level 3
Level 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
• Define niche:
#4
Ecological Role – including all interactions,
habitat, feeding behavior, mating,
competition, and other interactions with
organisms
• How does the “realized” niche differ from
its “fundamental” niche?
“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 growth
Under what conditions might you expect a
population to exhibit the growth
Why 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.
• 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: ( + + )
#9
• Define: Predation
• How does predator-prey relationships
differ from parasite-host relationship?
#11
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.
• Continued:
#11
• 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
• Mimicry of monarch butterflies by viceroys
#12
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.
• Continued:
• What is the advantage to a toxic species
of mimicking another toxic species?
#12
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.
• 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.
#14
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
• Growth of a population can be controlled
by either density-dependent or density
independent mechanisms.
• Define and contrast each.
#8
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
• Continued:
• Offer examples of how growth of the
human population might be curbed by
either agent.
#8
Density Dependent Factors: War, Famine, Disease
Density Independent Factors: Massive hot or
cold times
• Explain how character displacement can #10
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
• How is it possible to have an inverted
pyramid of biomass in which the
consumers have a greater biomass than
the producers?
#17
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.
• 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?
#17
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.
• 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.
#18