Ecology Study Guide KEY

Questions:Introduction to Ecology

1) Explain the difference between a habitat and a niche. Habitat is where the animal lives, while the niche is their role. Niche includes their habitat with what they eat, their interactions with other organisms, what they do for others, etc.

2) What are biotic factors and abiotic factors (give examples of each).Biotic factors are living things in the environment – animals, plants, dried leaves, logs; Abiotic factors are nonliving factors in the environment – sun, clouds, temperature, water, etc.

3) What is biodiversity?Variety of living things – higher biodiversity makes a healthier ecosystem.Energy Flow in Ecosystems and Food Chains, Food Webs, and Ecological Pyramids

4) What is the ultimate source of energy in ecosystems?The sun

5) Contrast an autotroph and a heterotroph.Autotroph – makes their own energy; producer, and Heterotroph – has to get their energy from

others; consumer6) Explain the difference between a producer and a consumer.

Producer makes energy while consumer eats energy 7) Define the following terms: herbivore, carnivore, omnivore, and decomposer.

Herb – eats producers, carn – eats consumer, omni – eats both, decomp – eats both when dead8) Distinguish between a food chain and a food web?

Food chain – single energy pathway, only one option; Food web – multiple pathways; options (biodiverse)

Species Interactions16) Define each of the following relationships and give an example of each: mutualism, commensalism, and parasitism.Mutualism – both benefit (+/+), Commensalism (+/0), Parasitism (+/-)

Refer to the food web image for the following questions:9) What do the arrows in a food chain or food web represent?Energy and matter transfer10) What is a producer in this food web?Flower11) Give an example of a primary consumer (1st order).Grub, caterpillar, grasshopper, aphid (small bug)12) Give an example of a secondary consumer (2nd order).Bird, mouse, beetle13) Give an example of a tertiary consumer (3rd order).Mouse, bird, owl14) What trophic level would an herbivore feed at?Primary consumer ONLY15) What trophic levels would a carnivore feed at?Second consumer and up

17) Contrast competition and predation.Competition – organisms wanting the same resource or filling the same niche

Predation – organism hunting and eating another organism Refer to the illustration to the left.18) How much energy is lost from trophic level to trophic level? Why?90% is released to the environment due to body processes (10% is passed on)19) Why do trophic levels top out at four to five levels?Energy within the ecosystem has been

released so that there is not enough to keep passing on

20) If bacteria eat the mountain lion as a decomposer, how much energy will they receive?

500 kcal

Populations21) What are density dependent factors? Give an example.

Limiting factors that depend on the population number – food, water, space, disease, competition, predation

22) What are density independent factors? Give an example.Limiting factors that do NOT depend on the population number – sunlight, temperature, climate,

natural disasters23) As prey increase in an ecosystem, what should happen to the number of predators?

They will increase as well after slight delaySuccession24) What’s illustrated in the image to the right?

Succession 25) Contrast primary and secondary succession.

Primary starts with bare rock and secondary starts with soil. Primary pioneer – lichens and bacteria, Secondary pioneer – grasses and weeds.

26) Define climax community.Final, stable stage with lots of biodiversity

27) How would soil be formed over time on a newly formed volcanic island? Would this be primary or secondary succession?This is primary succession. The pioneer organisms (lichens, bacteria, moss) break down the rock which pave the way for weeds, grasses, etc. These early organisms continue to break the rock into small pieces and as the organisms die they add nutrients.

Population Graphs28) Draw a graph showing carrying capacity

5,000,000 kcal

500,000 kcal

50,000 kcal

5,000 kcal

29) Draw a graph showing biotic potential

30) Contrast logistic and exponential growth Logistic growth is a carrying capacity graph like question 28, and exponential is a biotic potential

graph like question 29.