Download Ecology Review

ECOLOGY REVIEW - KEY
Ecology = word parts: The study of house
Ecology is very important on the TAKS test as well as in your understanding of the world around you. Fortunately, you have had a lot of
instruction on ecology already. Words like habitat, biome, acid rain, deforestation, and recycling are familiar to most of you, but there
is more to understanding our “house” than just that little bit. This unit is intended to deepen your understanding on things you are
familiar with and to introduce you to some new concepts that you aren’t.
1. Define ecology. - The study of the interactions of organisms with one another and their physical
environment
2. What is the difference between abiotic and biotic factors. List two examples of each. Abiotic – not
living, such as weather, wind, water, rock, soil; biotic – living, such as the organisms from all 6
kingdoms
3. Define ecosystem. A self-sustaining collection of organisms and their physical environment.
Both abiotic and biotic factors in a large area
4. What is the difference between a habitat and a niche? - A habitat is a place where an organism
usually lives while a niche is the habitat PLUS the function of the species in the biological
community (what it’s doing, it’s role in food webs, etc)
5. Define: individual, population, community, ecosystem and biome.
Individual – a single organism (specimen)
Population – all the members of a single species living in the same geographic area
Community – all the species living in a single area (habitat) and interact with each other
Ecosystem – a community of organisms and their abiotic environment (abiotic + biotic)
Biome – large region characterized by a specific type of climate and certain types of plant and
animal communities
Note that individuals make up populations, populations make up communities, which make up
ecosystems which make up biomes…. Only ecosystems and biomes include the abiotic factors
6. What are 5 limiting factors in an ecosystem? Competition (for food, water, mates, space), predation,
parasitism, crowding, stress, disease
7. What does the term carrying capacity mean? Maximum population size a population can sustain
8. Draw an example of a food chain that starts with grass and ends with a coyote. Then connect it to two
other food chains, making a food web.
Algae  fish  hawk
Grass  grasshopper  frog  coyote
Seed  bird snake  owl
9. Compare:
Producers – are typically autotrophs, usually photosynthetic; 1st trophic level; typically plants
and algae
Primary consumers – are heterotrophs, usually herbivores although can include omnivores; 2nd
trophic level; typical examples include deer, cows, grasshoppers, termites
Secondary consumers – are heterotrophs, usually omnivores or carnivores; 3 rd trophic level;
typical examples include frogs, pigs, humans, fish, snakes, etc
Tertiary consumers – are heterotrophs, almost always carnivores; 4th trophic level; usually the top
of a terrestrial food chain; typical examples include hawks, bears, coyotes, wolves, owls
decomposers. – organisms capable of breaking down the bodies and waste of dead/dying
organisms into the nutrients that can be used/recycled in the biogeochemical cycles, such as the
nitrogen cycle and the carbon cycle
10. List the average amount of energy amount that moves from trophic level to trophic level from prey to
predator. __10__%
What happens to the other %? The other 90% is either used by the organism or given off as heat.
11. Explain the following terms (not definitions, explanations)
a. Primary succession – occurs after an event that wipes away any trace of an ecosystem
leaving just bare rock to begin from; glaciers receding leave the granite exposed which
then are inhabited first by lichens and bryophytes until enough soil is created to allow
other seeds to germinate, then insects can move in; these organisms are then replaced
over time by larger species better adapted to the new environment created; the
slower/longer of the two processes – probably at least 500 years
b. Secondary succession – occurs after an event that destroys the ecosystem present but
leaves behind the soil; small plants (annuals) can immediately begin growing, providing
habitat for small vertebrates and invertebrates which then gives way to larger organisms
better adapted to the new environment created; the faster/shorter of the two processes –
probably 200 years
c.
Pioneer species – the first organisms capable of living in an area; typical examples
include lichens, mosses and other bryophytes
12. Give examples of at least three predator-prey relationships. Lynx-hare; sea slug – anemone; lionwildebeest
13. What are the three types of symbiosis? Describe & give examples.
Parasitism – symbiotic relationship in which one organism (the parasite) is benefitting while the
other organism (the host) is being harmed; ectoparasites include ticks, mites, lice, fleas,
leeches, some fungi, and some bacteria; endoparasites include some fungi, some bacteria,
many protists (Giardia, Plasmodium, Trypanosoma, Amoeba), tapeworms
Commensalism – symbiotic relationship in which one organism (the commensal) benefits while
the other organism (the host) is not affected; a remora that eats fish bits after a sharks meal, a
clown fish that is protected by an anemone, a barnacle hitching a ride to new food sources on a
whale are all given as examples of commensalism (so was the anemones on the claws of the
boxer crab)
Mutualism – symbiotic relationship in which both organisms are benefiting, such as the birds
that pick out and eat the scraps in an alligator’s teeth which prevents decay, bacteria that
metabolize cellulose in the guts of herbivores, E. coli in the human intestine stealing nutrients
while helping us with digestion as well as vitamin K production; lichens, mycchorizae
14. What is the difference between an omnivore, herbivore, carnivore, & detritivore?
Herbivores are primary consumers that eat only plants (producers). Omnivores are secondary
consumers (typically) that eat both plant material and other animals. Carnivores are generally
secondary or tertiary consumers that eat other animals (only). Detritivores are organisms that
feed on the organic waste produced by other organisms due to metabolism (urine, fecal matter,
vomit, etc) and on the bodies of dead organisms. The term detritus refers to this offal present in
all ecosystems. It is not the same thing as a scavenger. Detritivores include decomposers such
as fungi and bacteria, as well as some worms, insects, other arthropods, and some bottom
feeding fish such as catfish. A scavenger is an organism that takes advantage of a kill made by
another organism of just of the fact that there is a “fresh” meat source around such as vultures,
hyenas, sometimes coyotes, and other opportunistic carnivores.
15. Compare a J curve and an S curve? Which is most common? J-curves describe the exponential
growth seen in some populations that grow at a continuous rate until they deplete their
resources, then they go bust. Bacteria, many insects, and many flowering plants exhibit Jcurves. S-curves describe the logistic growth seen in some populations that grow slowly,
quickly reach carrying capacity, and then hover around carrying capacity in a fairly stable
population size. Humans, tigers, bears, and whales usually exhibit logistic growth.
16. Describe how a predator can affect a prey population. If there are too many predators, the prey
population will decrease (too few it will increase). If there are limited prey options around, the
prey populations that are present will decrease.
17. There are three cycles that circulate water, carbon, and nitrogen. Briefly describe each one and its
major steps. the water cycle includes both biotic and abiotic portions. Transpiration is a biotic
portion of the water cycle in which water is lost off the surface of a leaf as it leaves a stomate.
Evaporation, condensation, and precipitation are all abiotic portions of the water cycle.
Carbon is also cycled biotically through photosynthesis and cellular respiration, but abiotic
portions include decomposition, burning fossil fuels, and the release of calcium carbonate from
limestone deposits in bodies of water. When photosynthetic organisms are removed from
ecosystems, such as the destruction of the rain forests it interferes with the C cycle.
The nitrogen cycle involves the actions of several types of bacteria in cooperation with plants in
the soil. Bacteria can fix atmospheric nitrogen into the soil; other bacteria can convert the
nitrogen to nitrates that plants can take up. Other bacteria release nitrogen from tne soil due to
denitrification. Some breakdown the ammonia produced when organisms decompose or that
his present in their liquid waste resulting from protein breakdown in their bodies.
18. Which cycle(s) involve both abiotic and biotic factors? Carbon and water
19. Which cycle involves photosynthesis and respiration as major parts? Carbon (and water can be
argued)
20. In which cycle do bacteria in the soil play a key role? nitrogen
21. Explain the different roles of the bacteria discussed above. (see first answer)
22. What process forms clouds? condensation
23. Which part of the water cycle involves plants? transpiration
Also study biomes notes (powerpoint
printout) and pollution notes (on the back
of your ecology and energy notes) as
there are several questions on those
topics, too!
You will also need to study: any notes, worksheets, quizzes, and labs. Remember- Study everything we have
talked about it in this unit. A review sheet is just a GUIDELINE to begin studying. Utilize chapters 15,16, 17 and
18 in your textbook.