BIO 2 GO!
All things are either abiotic or biotic.
Ecosystems are determined by which of these factors are found in them.
Interactions among organisms are determined by their place in the ecosystem.

Abiotic/ Biotic Factors
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Objective: You should be able to
1) Determine if something is abiotic or biotic
2) Analyze the relationships between biotic diversity and abiotic factors
3) List the five interactions that organisms demonstrate.
4) Define, explain, and give examples for each of the following: a.
abiotic factors b.
biotic factors c. predator-prey d. parasite-host e. mutualism f. commensalism g. competition

Abiotic/ Biotic Factors
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1.
Abiotic Factors
Abiotic Factors are the non-living parts of an ecosystem. Some examples of these are water, soil, light, and temperature. We need these things to live, though not directly. They help the food we eat to grow. Can you imagine what would happen to us if we did not have any sunlight? How long could we survive?
REMEMBER THIS!!!
Abiotic factors are non-living.
Question 1: What are some other abiotic factors not listed above?
2.
Biotic Factors
Biotic Factors are the living parts of an ecosystem. Plants and animals are biotic factors. Humans are animals and are therefore biotic factors.
REMEMBER THIS!!!
Living organisms are biotic factors in an ecosystem
Question 2: What are some examples of organisms that are biotic factors?

Examine the chart below. It may help you remember the difference between abiotic and biotic factors. Remember, abiotic = non-living; biotic = living.
Abiotic
Non-living
Air
Water
Temperature
Biotic
Living
Plants
Animals
Sunlight
Space
REMEMBER THIS!!!!!
Ecosystems are made of biotic and abiotic factors.
Interesting Science Fact: Eco- in the word ecology comes from a Greek word
oikos, which means “house”, and –logy means the “study of”. So, when you put the two parts together it means “the study of the house”. Our house is the Earth! We can say then that it means the study of things on the Earth.
Relationships in an Ecosystem
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Interactions:
Whenever two or more organisms are close together, they interact. These interactions are organized into five different types. These relationships can be categorized according to the interactions different organisms have with each other.
There are 5 types of interactions:
1.
predator-prey
2.
parasite-host
3.
mutualism
4.
commensalism
5.
competition

1.
Predator- prey
In this type of interaction one organism, the predator, feeds on
(eats) another, called the prey. The prey dies.
Examples: A lion eating a zebra
A frog eating a fly
A hawk eating a mouse
This interaction is also called predation.
2.
Parasite- host
This interaction between organisms is a lot like predation. However, in this case one organism lives in or on another organism, but it
usually does not kill its host (the organism it is living on). If the parasite kills the host then it may die too, so it does not usually do this.
Examples: Ticks, mosquitoes, and fleas biting/living on an organism
(like us!) Tapeworms and hookworms that live inside of a host
This interaction is also called parasitism.
Question 3: What is the main difference between predation and parasitism?
3.
Mutualism
This is a type of relationship called symbiosis. Symbiosis means two or more species (organisms) live together in a close, long-term
association. Parasitism, as mentioned above, is a type of symbiosis that is harmful (not so good) for the host (the organism it is living in or on).
Mutualism is a good relationship between organisms! Both organisms benefit (are helped) by the relationship.

An example of mutualism is lichens. Lichens are fungi and algae that live together. The fungi give the algae a place to live and the algae give the fungi food because it does photosynthesis (which as you know is a process that makes sugar). Neither organism can live without the other.
4.
Commensalism
In this type of interaction one species benefits and the other one is
not helped or harmed- it does not care at all.
An example of commensalism is small tropical fish living around sea anemones (marine animals that having stinging tentacles). Most organisms are paralyzed by the tentacles, but the little fish are not, so they are protected from predators while they are in there. The sea anemones do not care if the fish are there or not, but the fish get protection.
Question 4: What is the difference between Mutualism and Commensalism?
5.
Competition
This is when two organisms are fighting for the same resource
(food, shelter, space, and mates). This usually does not happen unless one of the resources that an organism needs is in short supply.
Sometimes the organism will physically fight for the resource, but most of the time they do not. One organism will take the resource and the other organism will not have it at all.
Examples of this are all over the place. When the weather people on
TV predict a snowstorm is about to happen everyone runs to the grocery store to buy milk and bread. If you are the last one to get to the store there will not be any for you to buy- it will be all gone! That is competition.
Question 5: Give 2 more examples of competition.

Summary
Ecosystems have two main parts to them- abiotic and biotic factors. Abiotic factors are the non-living parts of the ecosystem. Biotic factors are the living parts of the ecosystem.
There are 5 types of interactions among organisms:
1.
predator-prey
2.
parasite-host
3.
mutualism
4.
commensalism
5.
competition
These interactions occur whenever two or more organisms live close to each other.
Matching
_____1. Commensalism
____ 2. Predator
____ 3. Mutualism
____ 4. Competition
____ 5. Parasite
____ 5. Prey
____ 6. Host
A.
Organism that is eaten.
B.
Both organisms benefit.
C.
Feeds on another organism, but usually does not kill it.
D.
Two organisms fight over a resource.
E.
Organism that is fed upon, but not killed.
F.
One organism benefits, the other does not care.
G.
Organism that kills the other for food.

True or False
_____ 1. Biotic factors in a habitat include all the physical aspects as well as the living organisms.
_____ 2. Biotic factors of a habitat include all abiotic factors.
_____ 3. A change in the number of predators or prey in a food web can alter the entire ecosystem in which they live.
_____ 4. A long-term relationship in which both species benefit is known as parasitism.
_____ 5. Predation is an example of a biotic interaction.
_____ 6. Mutualism is a symbiotic relationship in which only one party benefits.
_____ 7. Competition happens when organisms fight over the same resource.
_____ 8. Commensalism is when neither organism benefits.
_____ 9. The host is always killed in parasitism.
_____10. All organisms interact with each other directly or indirectly.
Complete the Chart
Use (+) if the organism is benefited.
Use (-) if the organism is harmed.
Use (o) if the organism is not affected.
Competition
Mutualism
Commensalism
Organism A Organism B
+ -
Parasitism
Predation

Fill in the Blank
Competition host mutualistic
Predation commensalism parasitism
1.
In a parasitic relationship, the organism that provides benefits to another organism at its own expense is called the ____________________.
2.
The general term for the biotic relationship in which one organism feeds upon another is ____________________.
3.
A symbiotic relationship in which one organism benefits and another is often harmed but not killed is called ____________________.
4.
The symbiotic relationship in which one organism benefits and the other neither benefits nor suffers harm is called ____________________.
5.
A fish called a cleaner wrasse eats the tiny parasites that cling to and feed upon much larger fish. Therefore, the cleaner wrasse has a(n)
________________ relationship with the larger fish.
6.
The struggle among organisms for the same limited natural resources is called ____________________.
Answer the following:
1. Describe the difference between biotic and abiotic?

2. Give some examples of biotic factors in your environment. Do not use examples listed in the chart above.
3. Give some examples of abiotic factors in your environment. Do not use examples listed in the chart above.