CP Biology Name:__________________________________
Date: ______
Unit 1B Intro to Ecology
Study Guide
In nature, everything is connected. Remember the hierarchy of organization in the living world?
Atom molecule  organelle  cell tissue  organ  organ systems  organism 
Species  population  community  ecosystem  biome  biosphere
1. What is an ecosystem?
All of the living and not living components in an area
2.
Give an example of an ecosystem.
Forest; pond
3.
An ecosystem is made up of both biotic and abiotic factors. What is a biotic factor? Give
some examples.
A living part of the ecosystem: plants, animals, bacteria, fungi, protists
4. What is an abiotic factor? Give some examples.
A non-living part of the ecosystem: land/soil, atmosphere, water, weather/climate
5.
Classify the following as biotic or abiotic or both:
a. Rocks: A
b. Pine trees: B
c. Waterfalls: A
d. Clouds: A
e. A mushroom in the soil: B/A
f. A fish swimming in a lake: B/A
6. Give an example showing how a biotic factor and an abiotic factor interact with one another.
Fish swim in water; organisms breathe in gases in the air
7.
Define organism.
An individual of a certain species
8. What is a species?
A group of organisms that can breed and produce fertile offspring
9.
What is a population?
A group of the same species living in a certain area
10. What is a community?
All the different populations of species in an area
11. Explain the difference between a population and a community?
A population is one species and a community is many species
Materials and energy move between the living (biotic) and nonliving (abiotic) parts of
ecosystems. Materials (atoms, molecules) must be recycled, but energy is NOT! So, a constant
supply of energy must enter every ecosystem.
12. On Earth, what supplies our energy?
sun
Remember from unit 1, organisms must be able to produce or obtain nutrients, convert the
nutrients into usable forms of chemical energy (cellular respiration – producing ATP!!), and
then use these forms of energy to power their life processes.
13. Through what process does the sun enter an ecosystem? (hint: In this process, the plant uses
sunlight to make sugar molecules.) photosynthesis
Organisms obtain their food in different ways. Some organisms are producers, while others are
consumers.
14. What is a producer? What is another term for producer? Give some examples of
organisms that are producers. Organisms that make their own food by photosynthesis;
autotrophs; plants, algae
15. What is a consumer? What is another term for consumer? What are some examples of
organism that are consumers? Organisms that must eat other organisms for food; heterotroph;
animals, fungi, some bacteria.
16. What is a decomposer? Why are decomposers so important to ecosystems?
Organisms that break down dead organisms. They recycle nutrients back to the earth so that
new life can grow; they are the clean up crew
17. There are several different types of consumers in ecosystems: herbivores, carnivores,
omnivores, decomposers, detritovores and scavengers. Fill in the following table describing
how each type of consumer gets its food, and give some examples of each.
Type of consumer
Energy Source
Examples
Herbivore
plants
rabbit
Carnivore
animals
fox
Omnivore
Plants and animals
raccoon
Decomposer
Dead plants or animals
Bacteria/fungi
Detritovore
Broken down dead material
called detritus
worms
Scavenger
Dead carcasses of animals
vulture
Energy Transfer
Each time an organism eats another organism, a transfer of energy occurs. We can trace the
transfer of energy as it travels through an ecosystem by studying food chains, food webs, and
trophic levels. These tell us how and how much energy is transferred between organisms in an
ecosystem.
18. What is a food chain?
A series of steps showing the transfer of energy through food
19. What is a food web? Why is a food web really a better way than a food chain to depict
energy transfer in an ecosystem?
All of the complex feeding relationships in an ecosystem. It shows all of the ways organisms
eat or are eaten.
20. What is a trophic level?
A step in the food chain or web/energy level
21. What does an energy pyramid show us?
How much energy is available at each trophic level
22. In an energy pyramid, which trophic level has the most energy available to it? What
happens to the amount of energy available to the organisms as the trophic levels go up? How
much? Explain why this happens.
The bottom (producers). Energy decreases as you go up the pyramid because only 10% is passed
from one tropic level to the next.
The rest of the energy is used up by the organisms for life processes or is lost as heat.
23. Draw an energy pyramid for a four step food chain.
(make sure to show the producer and each level of consumer)
24. If 100% of the energy is available at the first trophic level, what percentage of that energy is
available at each of the next trophic levels?
2nd tropic level- 10%
3rd trophic level- 1%
4th trophic level- 0.1%
25. Let’s use calories. If 8000 calories of energy are available at the first trophic level, how
many calories are available at each of the next trophic levels?
2nd tropic level- 800
3rd trophic level- 80
4th trophic level- 8
26. _____________always make up the first trophic level in a food web.
a. producers
b. primary consumers
c. secondary consumers
27. Energy pyramids show the relative amount of energy contained within each trophic level in a
given food web.
a. true
b. false
28. On average, about __________ percent of the energy available within one trophic level is
transferred to the next trophic level.
a. 90%
b. 10%
c. 50%
d. 100%
29.Fill in the pyramid below using the following food chain:
Grass (P)  mice (PC)  snake (SC)  hawk (TC).
Indicate which organism is the producer, primary consumer, secondary consumer and
tertiary consumer:
Use the following food chain to answer the questions below.
Algae  flag fish  largemouth bass  anhinga  alligator
30. Which organism is the producer? algae
31. Which organism is an herbivore? Flag fish
32. Which organism is a secondary consumer? Largemouth bass
33. Which organism is at the third trophic level? Largemouth bass
34. Which organism(s) is/are carnivores? Largemouth bass, anhinga, alligator
35. Which organism is a tertiary consumer? anhinga
36. Which organism is at the second trophic level? Flag fish
37. What would happen to the population of largemouth bass if the population of alligators
suddenly decreased a great deal? Alligator decrease means an increase of anhinga birds, and
thus a decrease of the bass because they will be eaten more frequently.
38. What type of pyramid is shown below? Pyramid of biomass
39. Producers have the __most__ biomass, while the top consumers have the least.
Pyramid of Numbers
40. Pyramids of numbers show the numbers of organisms at each trophic level. According to the
pyramid of numbers in the diagram above, which trophic level has the fewest number of
organisms?4th trophic level, but the 1st trophic level has very few too!
41. What can you conclude about the size of the elder tree in the pyramid above? How do you
know this? It is a large tree. The bar is small so there are only a few of them, so they must be
big enough to provide food for the huge amount of aphids (bugs) that are in this ecosystem.
42. Arrange the following in order from most broad to least broad:
Biome, biosphere, organism, community, population, ecosystem
Biosphere, Biome, Ecosystem, Community, Population, Organism
43.The place where an organism lives is called its ___habitat____.
44.What an organism does in its habitat, how it interacts with its environment, and how it
contributes to an ecosystem is known as the organism’s ___niche________.
45.Give an example of a biological aspect of an organism’s niche, and give an example of a
physical aspect of an organism’s niche.
Biological- bear eats fish
Physical- bear creates a den out of the earth
46.Describe what happens if two different species try to occupy the same niche at the same time.
Because of the competitive exclusion principle, we know that if this occurs, one species will die
out or move away. A third option is for both species to split the niche.
47. In which biome do you live?
Temperate (deciduous) forest