BIOLOGY I

Chapter 2: Principles of Ecology

Section 1: Organisms and Their Relationships

Ecology – the scientific study of interactions between living organisms and their environment

Environment includes: Physical surroundings, climate, interactions with

other living organismsEcology also includes the study of the

biosphereBiosphere – the portions of the planet in

which life exists For example: Land, water, air, or space

Biotic and Abiotic Factors

Organisms living within ecosystems are influenced by a wide range of environmental factors.

There are two types of factors: Biotic Abiotic

Together, these factors determine: The survival and growth of an organism/species. The success of an ecosystem

What are They?

Biotic factors Factors that are LIVING! (Bio = life!) For example: plants, animals, bacteria, fungi

Abiotic factors Those factors that are NONLIVING! (A = not!) Often related to climate and weather For example: temperature, sunlight, wind, soil,

precipitation, humidity, pressure

Levels of Organization

Remember the cellular levels of organization?? Cell Tissue Organ Organ System Individual

There are 6 levels of ecological organization: 1. Individual 2. Population 3. Community 4. Ecosystem 5. Biome 6. Biosphere

How Do I Remember Those?

Remember “My Very Educated Mother Just Served Us Nachos?” Used by many to remember the planets

Use this to remember the 6 levels of ecological organization: In Paris cows eat buttered bread. I = individual, p = population, c = community, e =

ecosystem, b = biome, b = biosphere

RA Activity

Each group will be assigned one of the levels of organization. Group 1 – Individual/Organism Group 2 – Population Group 3 – Community Group 4 – Ecosystem Group 5 – Biome Group 6 – Biosphere

Your group will become the expert on your assigned level and then make a poster explaining YOUR LEVEL ONLY!

We will do a gallery walk to learn about the levels; take notes as you tour the posters (a tree map would be a great way to organize your notes for this!)

Homework – create your own diagram showing each of the ecological levels of organization

More About the Levels

Level One: Individual – an organismCharacteristics of an individual or living

thing: Have cells Sense and respond to change Reproduce Have DNA Use energy Grow and develop

Examples: human, giraffe, daisy, tree

Levels, Continued

Level Two: Population – a group of individuals of the same species living in the same geographic area For example: humans in Avon, snapping turtles in a

pond, deer in a certain forest

Levels, Continued

Level Three: Community – different populations that live together in the same geographic area For example: All animals that live in Avon (mice,

rabbits, dogs, cats, humans)

Level Four: Ecosystem – a collection of communities in an area plus the abiotic factors Includes living and nonliving components For example: Pond (H2O, fish, turtles, bacteria, plants)

Levels, Continued

Level Five: Biome – a group of ecosystems that have the same climate and communities present For example: Indiana, Midwest Region, Desert

Level Six: Biosphere – the portion of the Earth in which all life exists

Habitats

A habitat is an area where an organism lives!

Include biotic and abiotic factorsFor example: Turtle’s habitat

Abiotic factors: water, temperature, sun, mud/dirt Biotic factors: fish, other turtles, bacteria, plants

Niches (rhymes with witches)

A niche is the role an organism plays in an ecosystem

Includes a full range of biotic/abiotic factorsSuch as:

Living environment – Where in an ecosystem does that specific species live?

Eating – What does it eat? How does it obtain food? Reproduction – How many mates are available? When is

mating season? Climate – Are there changes in temperature? Humidity? Competition – With what do I have to compete for mates,

food, and space?

Community Interactions

Organisms in a community must interact with each other to obtain food, space, mates, etc.

There are three types of community interactions: Competition Predation Symbiosis

Competition

Competition is when organisms of the same or different species attempt to use an ecological resource at the same time. A resource is any necessity of life. For example: water, light, food, space

Examples of competition include: Two crocodiles competing for a place to lay eggs Three female songbirds competing for a male mate Geese and ducks competing for a nest around a

retention pond

Predation

Predation is an interaction in which one organism captures and feeds upon another

There are TWO organisms present Predator – the organism that is KILLING and EATING

For example: tiger, anaconda, lion

Prey – the organism being eaten For example: rabbit, mouse, antelope

PREDATOR: SLY FOX

PREY: POOR LITTLE RABBIT

RA Activity

On pages 39 and 40 in your Zebra text, read all 3 types of symbiotic relationships . Quickly summarize ALL 3 relationships on your

CH 2 Notes PacketListen for EXAMPLES OF EACH in the

“Magic School Bus” video as you do your worksheet. Magic School Bus Symbiosis

Using the info from the video, your text, and your table partner, do a Think Aloud and summarize the three types of symbiosis at the bottom of your video worksheet.

Symbiosis

Symbiosis is any relationship in which two species live closely together

There are THREE types of symbiosis: Mutualism – both organisms benefit

For example: Flowers and insects Commensalism – one organism benefits, the

other is neither harmed nor helped For example: Birds on rhino/antelope’s backs; sharks and

ramora fish; whales and barnacles Parasitism – one organism hurts, the other

benefits For example: Tick and humans; fleas and dogs

Mutualism

Parasitism

Commensalism

Commensalism

Section 2: Flow of Energy in an Ecosystem

All living things need energy to power every little thing they do; the flow of energy through an ecosystem is VERY important!

Things to think about: Where does the energy for life processes come from? How does energy flow through living systems? How efficient is the transfer of energy among

organisms in an ecosystem?

Producers

Producers are organisms that produce their own food They often use sunlight /special pigments to produce

foodAlso known as autotrophs

Auto = self; troph = feeder For example: plants and algae

Producers rely on two types of energy to make food: 1) Sunlight 2) Other chemicals

(chemotrophs)

Sunlight & Chemicals

Sunlight Photosynthesis – when plants use sunlight, water, and

carbon dioxide to make food For example: Plants and algae

Other chemicals Chemosynthesis – when bacteria use other chemicals

to produce food because they don’t have a source of sunlight

Generally use methane or hydrogen gas For example: bacteria at the bottom of the ocean

Consumers

Consumers are organisms that can’t produce their own food

Also known as heterotrophsFor example: Any animal (human, mouse,

elephant)Consumers rely on energy from the sun

INDIRECTLY They will often eat autotrophs to obtain food/energy They often also eat other heterotrophs to obtain

food/energy

Consumers, Continued

There are 5 types of consumers.1. Herbivores – animals that only eat

plant material For example: rabbits, cows, most insects

2. Carnivores – animals that only eat meat/animals For example: hawks, tigers, snakes

Consumers, Continued

3. Omnivores – animals that eat both plants and animals For example: Humans, black bears, crows

4. Insectivores – these eat only insects For example: Most reptiles and amphibians (turtles,

frogs, salamanders, etc.)

Consumers, Continued

5. Decomposers/detritivores – eat dead and/or rotting material For example: Bacteria, fungi, earthworms, snails, and

mites

Trophic Levels

Each step in a food chain or food web is called a trophic level.

1st Level: ALWAYS producers2nd, 3rd, and 4th levels: ALWAYS consumers

2nd level is always an herbivore – they eat plants/producers from level 1

First consumer = primary consumerSecond consumer = secondary consumerThird consumer = tertiary consumerFourth consumer = quaternary consumer

Trophic Level Examples

Food Chain: Flower Caterpillar

Frog Snake OwlFlower = producerCaterpillar = primary

consumerFrog = secondary

consumerSnake = tertiary

consumerOwl = quaternary

consumer

Food Chains

A food chain is a series of steps in which organisms transfer energy by eating (and being eaten).

Food chains show a one-way flow of energy.They use arrows to indicate the direction of

energy flow.For example: grass rabbit snake owl

Food Chain

Food Web

A food web is a network of complex food chain interactions.

Links all food chains in an ecosystem

More complex portrayal of energy flow

Shows all possible food chainsFig. 14, pg. 43

Food Web

More Examples

Ecological Pyramids

An ecological pyramid is a diagram that shows the approximate amounts of energy/matter contained within each trophic level in a food chain or web.

The amount of energy/matter will ALWAYS decrease as you go UP the pyramid.

There are three types of ecological pyramids: 1. Energy 2. Biomass 3. Numbers

Energy Pyramids

Energy pyramids show how much energy is transferred to each trophic level.

For example: grass rabbit owlHow much energy does the rabbit gets when

it eats the grass? How about when the owl eats the rabbit? Only 10% of the energy moves on to the next level! The rest of the energy is eliminated as heat.

For example: Grass (100%) Rabbit (10%) Owl (1%)

Biomass Pyramid

A biomass pyramid shows how much biomass there is at each level. Biomass is the amount of living tissue within a

given trophic level.Biomass is usually expressed in grams (g) or

kilograms (kg) per meter2

The greatest amount of biomass is at the bottom of the pyramid.

Numbers Pyramid

A numbers pyramid shows how many individuals are at each trophic level.

For example: blades of grass # of rabbits # of owls (per acre)

The greatest number of individuals is at the bottom of the pyramid!

Section 3: Cycling of Matter

Recycling in the BiosphereEnergy flows ONE-WAY!

From: the Sun producer primary consumer secondary consumer tertiary consumer

Matter has a cyclical (circular) flow What kind of matter can flow in a cycle? Elements, chemical compounds For example: water, carbon, nitrogen, phosphorus

The biogeochemical cycle is a cycle which passes matter through an ecosystem. For example: Water cycle, nitrogen cycle

Recycling in the Biosphere

A nutrient that is scarce or cycles very slowly is called a limiting nutrient.

The limiting nutrients limit an ecosystem’s productivity/success. For example: Space, water, nutrients, sunlight

Farmers often add nutrients to the soil (through the use of fertilizers) to make sure nutrients do not limit production of crops.

Water Cycle

All living things require water to surviveWater moves through the biosphere using the

water cycleParts of the Water Cycle

Liquid Gas (evaporation, etc.) Gas Liquid (condensation) Solid Liquid (melting) Liquid Solid (freezing) Movement of water on land (runoff, infiltration,

percolation) ***Fig. 17 p. 46

Water Cycle

LIQUID GASOccurs when water enters the atmosphere

and changes from liquid form to gaseous form (water vapor) 3 types

1. Evaporation – water leaving any water body (puddle, pond, lake, etc.)

2. Transpiration – water leaving plants (from the leaves)

3. Perspiration – water leaving animals (through the skin/pores)

Water Cycle

GAS LIQUIDThis occurs when water leaves the

atmosphere to fall to the ground or other bodies of water

Called condensation Gas molecules become so compacted (because there

are SO many of them in the clouds) that they combine to become liquid

Then the liquid falls as precipitation For example: Rain, sleet, snow, or hail

Water Cycle

OTHER WATER MOVEMENTS3 types

1. Runoff Water that drains or flows, water not absorbed by soil. Why? Because the soil/ground is saturated with water.

2. Infiltration When water is absorbed into the topsoil of the ground

3. Percolation A small amount of water will reach the depths of the ground This water becomes ground water (which can be used in

wells, etc.) Water Cycle Video Clip

Nitrogen Cycle

All living organisms require nitrogen to make amino acids (amino acids are used to make proteins)

N2 (nitrogen gas) makes of 78% of atmospheric gases Oxygen makes up only about 20%

Nitrogen- fixing bacteria are essential to the nitrogen cycle Helps to transform nitrogen into a useable form Found in plant roots and in the soil

Nitrogen Cycle Video Clip

Carbon Cycle

Carbon is the key ingredient for all living tissuesThere are 4 processes that move carbon:

1. Biological processes For example: photosynthesis, cellular respiration, decomposition

2. Geological processes For example: erosion, volcanic activity

3. Mixed processes For example: burial and decomposition of organisms

4. Human activities For example: mining, deforestation, burning fossil fuels Carbon Cycle Video Clip ***Fig. 18, page 47 Carbon Cycle BrainPop

Phosphorus Cycle

Read with your partner and do a Think Aloud about the Phosphorus Cycle on page 49 in the Zebra book

Take notes about all important parts! (Figure 21)

What do you notice about this cycle compared to the other three we’ve discussed?