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

  1. 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
  1. Define ecosystem.A self-sustaining collection of organisms and their physical environment.

Both abiotic and biotic factors in a large area

  1. 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)
  1. 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

  1. What are 5 limiting factors in an ecosystem? Competition (for food, water, mates, space), predation, parasitism, crowding, stress, disease
  1. What does the term carrying capacity mean? Maximum population size a population can sustain
  1. 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

  1. 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; 3rd 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

  1. 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.

  1. Explain the following terms (not definitions, explanations)
  2. 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
  1. 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
  1. Pioneer species – the first organisms capable of living in an area; typical examples include lichens, mosses and other bryophytes
  1. Give examples of at least three predator-prey relationships. Lynx-hare; sea slug – anemone; lion-wildebeest
  1. 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

  1. 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.

  1. 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 J-curves. 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.
  1. 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.
  1. 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.

  1. Which cycle(s) involve both abiotic and biotic factors?Carbon and water
  1. Which cycle involves photosynthesis and respiration as major parts?Carbon (and water can be argued)
  1. In which cycle do bacteria in the soil play a key role? nitrogen
  1. Explain the different roles of the bacteria discussed above.(see first answer)
  1. What process forms clouds? condensation
  1. Which part of the water cycle involves plants?transpiration

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.