Ecology

EcologyIt’s all about interactions!

Nature’s Interactions

• Ecology – the study of interactions among

organisms and their environment.– Abiotic (non-living) & Biotic (living) things

are considered.– Materials, such as nitrogen and carbon,

are exchanged back and forth from biotic to abiotic.

– Ecosystems throughout the world are linked together, and organisms move from one ecosystem to another.

Standard I; Objective 3

Nature’s Interactions

• Quick review of biotic and abiotic factors.Animals

PlantsBacteriaFungi

ProtistsDecomposing

matterDead, rotting logs

Leaf matterGrass clippings

Manure

SunlightWater

OxygenTemperature

SoilInorganic nutrients

RocksSand

NitrogenMetals

Biotic Abiotic

Relationships• There are many types of relationships

in nature. One example is predator/prey. This is an example of energy flow with predators getting their energy needs from what/whom they eat. Can you think of some predator/prey relationships?


Producers

Decomposers

Energy Flow• Energy flows in all ecosystems. All

food chains start with photosynthesis, and the energy passes from producers up through the consumers.

Herbivores

Carnivores

Project: Mini-Ecosystem

• You will now be asked to build/create a mini-ecosystem.

• Remember… an ecosystem is the interaction of all of the living and non-living things in an area.

Assignment 4-1• You will earn more points for creating an actual

ecosystem.

Symbiotic Relationships

• Another type of relationship is called symbiosis.

• Symbiosis means living together. There are several types of symbiosis.

• Mutualism = both organisms benefit• Parasitism = one organism benefits, one

is harmed• Commensalism = one organism benefits,

the other is neither harmed nor helped.Standard I; Objective

3

Examples of Symbiosis

Mutualism The Moray eel &

shrimp…The eel benefits from the shrimp cleaning bits of food from its teeth. The shrimp gets food, and most likely protection from predators that don’t dare come close to the Moray eel


ParasitismTick & Dog… The tick benefits by getting nutrition from the dog’s blood. The dog is harmed because of lost blood, and can pick up diseases from the tick.


Commensalism Dugong & Remoras…The Remoras attach themselves to many types of marine animals, and just hang on for the free ride. When the larger animal eats, the Remoras can benefit by picking up scraps. It doesn’t hurt or help the Dugong.

Niche vs. Habitat

• In a balanced ecosystem, each organism/species occupies it’s own niche (role) in an ecosystem. It also occupies a particular territory (habitat), and gets its nutrients in a certain way.

• Competition arises when the niches of two species overlap. Two can share a similar habitat, but must have a unique niche. The greater the overlap, the more requirements the two have in common, and the more intense the competition will be.

Relationship Assignment

• You have read and learned about different relationships that occur in nature. Symbiosis & Predator/Prey. Please complete the next assignment.

Assignment 4-2

Food Chains

• As you have seen, energy flows from the sun, to producers, to consumers, and back to producers.

Producers

Decomposers

Herbivores

Carnivores

Food Chains

• This flow of energy is called a food chain. Every chain starts with a producer, followed by various levels of consumers. Nutrients are returned to producers.

Primary Consumer

Producer

SecondaryConsumer

Tertiary ConsumerDecomposers

Food Chains• Organic material is passed through the food chain.

So a 4 level food chain would be… Grass Mouse Snake Hawk. Notice the arrows show the flow of energy.

1st Level Consumer

Producer

2nd LevelConsumer

3rd Level ConsumerDecomposers

Herbivores – plant eaters

Omnivores – could eat either carnivores or herbivores, or both.

Carnivores – meat eaters

Food Webs

• What’s the difference between a food chain and a food web? A food web is made up of many interconnected food chains. Can you see different food chains in this small food web?

Wolf

Rabbit

Hawk Snak

eGrass

Mouse

Notice how energy flows

from producer to consumers, and from consumers

to other consumers.

Food Chains & Food Webs

• Can you think of some food chains that occur in nature? Could you put them in to a food web?


Assignment 4-3

Energy Costs vs. Gains

• In all food chains, organisms are in a battle to gain more

than they spend when eating, fighting, migrating,

etc. It’s all about survival. In all food chains for example,

as you move from one level to another, 90% of the

energy is used to survive.Standard I; Objective

1

100 %10 %1 %

.1 %

1000 calories

100 calories

10 calories

1 calorie

If a plant makes 1000 calories of food, there is only 1 calorie left at

the 4th trophic level.

Activities that cost energy

• Many activities require an investment of energy by the organism. Some of them are…

• Growth• Migrations – some animals go thousands of miles

yearly• Fighting to breed, protect resources, obtaining

prey• Feeding – capturing, metabolism, expenditure of

waste• Hibernation – maintaining a constant body

temperature• Shelter/home building – bird nest, badger hole,

etc.


Nutrient Cycling

• There are 4 key nutrients that living things must have. When you think of matter, remember that matter, like energy, cannot be created or destroyed, it can only be converted from one thing to another and back. We will investigate the cycling of these 4 main nutrients.

• Water – used in nearly all bodily functions• Carbon – key component in all organic

compounds• Nitrogen – important in DNA, RNA & proteins• Phosphorus – part of DNA, RNA & ATP


Review the following cycles.

Water Cycle

Water cycles

from the earth to

the atmosphere. It’s one

of the nutrients all living things

must have.

Carbon Cycle

Carbon goes from CO2

in the atmospher

e to organic

compounds on earth.

A lot of CO2

comes from fossil

fuels burning.

Nitrogen Cycle

Nitrogen is fixed/pulled from the air by bacteria in plants, then made available to animals.

Nitrogen Fixation by Nitrogen fixing

bacteriaDe-nitrification converts solid

Nitrogen to N2 gas

Phosphorus Cycle

Phosphorus helps make phosphate which is needed by many living

things. It doesn’t go in to the

atmosphere, but goes from

mountains to lakes/oceans, to

plants, to animals and back to

earth.

Human Impact

• Have you ever stopped to think about what we do to the environment? Do we have a positive or negative impact?

Is it all just “Doom and Gloom”? Assignment 4-4

Invasive Species

• Organisms that are native to an area, are also called indigenous. Occasionally, organisms are introduced accidentally or intentionally in to an ecosystem. These species can be very disruptive, and are known as “Invasive species”. Please watch the short video on Cane Toads, then complete the next

assignment. It’s in the “Resources”.Cane Toads were

introduced to Australia to control Cane grubs.

Assignment 4-5

Documents

Ecology