Levels of Ecological Organization

BIO.B.4.1.1 Describe the levels of ecological organization (i.e. organism, population, community, ecosystem, biome and biosphere)

BIO. B.4.1.2 Describe characteristic biotic and abiotic components of aquatic and terrestrial ecosystems.

What is Ecology?

• Ecology is the study of interactions among organisms and between organisms and their environment.

• Biosphere contains the combined portions of the planet in which life exists, including land, water, and air or atmosphere.

Levels of Organization in the Biosphere

• Organism is any individual living thing.• Species is a group of organisms so

similar to one another that they can breed.

• Population are groups of individuals that belong to the same species and live in the same area.

• Community the different populations that live together in a specific area.

• Ecosystem is a collection of all the organisms that live together in a particular place as well as their nonliving or physical environment.

• Biome is a group of ecosystems that have the same climate and similar dominant communities.

• Biosphere is all living things and the places where they exist (air, land, water).

Biomes

• Include:– TUNDRA– TAIGA– DESERT– TROPICAL RAINFOREST– TEMPERATE RAINFOREST– DECIDUOUS FOREST– FRESHWATER– SALTWATER– GRASSLAND

Factors that Impact Ecosystems

Biotic Factors

• Biotic factors in an ecosystem = living factors• Plants• Animals• Fungi• Protists• Bacteria

Abiotic Factors

• Abiotic factors in an ecosystem = nonliving factors

• Water• Air• Soil• Temperature• Sunlight

What are the biotic and abiotic components of these aquatic ecosystem?

What are the biotic and abiotic components of these terrestrial ecosystem?

Energy Flow Through an Ecosystem

Food Chains, Food Webs, Energy Pyramids

BIO.B.4.2.1 Describe how energy flows through an ecosystem (e.g. food chains, food webs, energy pyramids)

•Begins with the SUN

•Photosynthesis

6CO2 + 6H2O + sunlight & chlorophyll C6H12O6 + 6O2

• The chemical reaction by which green plants use water and carbon dioxide and light from the sun to make glucose.

• ENERGY is stored in glucose; glucose is stored as starch.

Organisms that can make glucose during

photosynthesis are called PRODUCERS or AUTOTROPHS.

Producers use most of the energy they make for

themselves.

Producers use cellular respiration to supply the energy

they need to live.

CELLULAR RESPIRATION is the chemical reaction that releases the

energy in glucose.

6O2 + C6H12O6 -->  6H2O + 6CO2 + energy

The energy that is not used by producers can be passed on to

organisms that cannot make their own energy.

Self-Sustained Ecosystems

Organisms that cannot make their own energy are called

CONSUMERS or HETEROTROPHS.

Types of Heterotrophs

• Saprophytes: plants, fungi and bacteria which live on dead matter (AKA = decomposers).

• Herbivores : plant-eating animals• Carnivores: meat-eating animals

• Types of Carnivores» Predators – animals which kill and consume

their prey» Scavengers – those animals that feed on

other animals that they have NOT killed.• Omnivores: plant AND meat eaters

Trophic LevelsTrophic Levels = locations within a food chain:• Primary producers: photosynthetic organisms (plants, algae, some

bacteria)• Primary consumers: consume primary producers• Secondary consumers: consume primary consumers• Tertiary consumers: consume secondary consumers

Energy flows through ecosystems in one direction, typically from the sun, through photosynthetic organisms, including green plants and algae, through herbivores, to

carnivores and finally decomposers.

SUN PHOTOSYNTHETIC ORGANISMS HERBIVORES CARNIVORES DECOMPOSERS

Trophic Level Nutrition

• Autotrophic nutrition – Photosynthesis (from CO2 & H2O)

• Heterotrophic nutrition – Respiration (from eating food)

Most of the energy passed from one consumer to the next is used

by the consumer.

Some of the energy is lost and moves into the atmosphere as

heat.

Some energy is stored and can be passed on to

another consumer.

Food Chains and Food Webs

• If an ecosystem is to be self-sustaining it must contain a flow of energy.

• The pathways of energy through the living components of an ecosystem are represented by food chains and food webs.

• Producers initiate the flow of energy by converting solar energy (sunlight) into the chemical energy (ATP) from food.

A food chain involves the transfer of energy from green plants

through a series of organisms with repeated stages of eating and

being eaten.

Food Webs:

• A group of interconnected food chains

• They show the feeding relationships in an ecosystem

Energy Transfer Is Also Modeled Through Pyramids

•Energy Pyramids – indicates the amount of energy transferred to each trophic level•Biomass Pyramids – indicates the total mass for all species at each trophic level•Pyramid of Numbers – indicates the number of organisms at each level

Energy Pyramids• An Energy Pyramid is a diagram that shows

the relative amounts of energy or matter contained within each trophic level in a food web or food chain.

• Energy Pyramid only 10% of the energy available within one trophic level is transferred to organisms at the next trophic level.

• There is much more energy in the producer level of a food chain than at the consumer levels.

• Energy input usually = SUN.

• Only 10% of the energy from the sun is captured by producers.

• Only 10% of the energy available in producers is transferred to consumers

Biomass Pyramid

Pyramid of Numbers

Which One????

• Shows an ecosystem containing one tree, many herbivores, many omnivores, and one carnivore (eagle)?

Biotic Interactions In An Ecosystem

Symbiotic Relationships

BIO.B.4.2.2 – Describe biotic interactions in an ecosystem (eg., competition, predation, symbiosis)

Symbiotic Relationships

• Symbiotic relationship = relationship between two organisms• Types of Symbiotic Relationships

1. Mutualism

2. Parasitism

3. Commensalism

MUTUALISM PARASITISM COMMENSALISM

Mutualism

• Mutualism – a type of symbiotic relationship in which both organisms benefit

• Examples:– Oxpecker feeds on the ticks of rhinos.– Acidophilus bacteria in the human digestive tract.

Bacteria get nutrients from the human and the human digestive process is assisted.

Parasitism

• Parasitism – a type of symbiotic relationship in which one organism benefits and the other is harmed

• Examples:– A tick feeds off a deer’s blood.– A tapeworm feeds off a human stripping it off valuable nutrients.

Commensalism• Commensalism – a type of symbiotic relationship in

which one organism benefits and the other organism does not benefit or is not harmed.

• Examples:– Hermit crab lives in a snail shell.– Barnacles attach themselves to whales.

Habitat vs. Niche• Habitat: an area that provides an organism with its basic needs for

survival. (Like food, shelter, temperature, moisture, etc...)• Niche: the role an organism plays in its ecosystem (aka - an

organisms job)• An organisms location in a food chain helps to determine its

niche.• An organisms structure or shape determines its function which

influences its niche.

• Fitness: a measure of an organisms health as determined by its ability

to produce offspring (a measure of population size)

Competition

• Competition: occurs when two different species or organisms living in the same environment (habitat) and use the same limited resources such as:

»Food»Water»Space »Light»Minerals

Competition • Competition reduces fitness (population size) of one or both species.• Types of competition:

– Intraspecific competition

Competition between members

of the same species– Interspecific competition

Competition between members

of different species• The more similar the requirements of the organisms involved, the

more intense the competition. • Two organisms can share the same HABITAT but not occupy the

same NICHE!

Predator-Prey Relationships

• Predation: one species feeds on another• Predation will improve the fitness of the

predator, but reduces the fitness of the prey.

Ecological Roles• Specialist: organism that eats a particular type of food and/or lives

in a specific environment (small range)• Examples:

– Koalas– Cactus– Giraffes

• Generalist: organism that eats many types of food or lives in a wide range of environments

• Keystone Species: a species that is at the center of a food web and has an unusually large impact on its ecosystem– American Alligator: makes “alligator holes” in

the Everglades that serve as a source of food

and water for other animals during droughts

Recycling Matter in Ecosystems

Water Cycle, Carbon Cycle, Oxygen Cycle

And Nitrogen Cycle

BIO.B.4.2.3 – Describe how matter recycles through an ecosystem (ie. Water cycle, carbon

cycle, oxygen cycle, and nitrogen cycle)

Recycling Matter

• In a self-sustaining ecosystem, materials must be cycled between organisms and the abiotic environment…this is where processes like photosynthesis and cellular respiration play important roles.

• Materials constantly need to be recycled from the living and non-living environment so that materials can be reused by different living organisms in order to maintain biogeochemical cycles and hydrologic cycles like the water cycle, oxygen cycle, carbon cycle and nitrogen cycle..

Water CycleInvolves the following processes:

•Precipitation

•Evaporation

•Condensation

•Transpiration

Water Cycle Terminology• Evaporation – water separates into hydrogen and oxygen molecules

due to a rise in temperature• Condensation – water collects due to a drop in temperature• Precipitation – water falls from the clouds due to changes in

temperature and pressure• Surface Water and Groundwater – water collects or runs from one

region to another• Transpiration – plants draw water up from the ground and release it through their stoma (openings) in the leaves

Carbon Cycle

Carbon is added to the atmosphere (CO2) by the following:•Combustion - Burning of Fossil Fuels (exhaust)•Respiration – From ALL organisms, aquatic and terrestrial•Natural Events – Volcanism

Carbon is removed from the atmosphere (CO2) by the following:•Photosynthesis – From aquatic and terrestrial organisms

Carbon is transferred between the earth and living organisms by:•Consumption - Carbon is transferred from plants to animals

through organic molecules like carbs, lipids and proteins.In other words….Carbon passes through food chains and food webs as one organism consumes the next.•Decomposition – Carbon molecules from dead organisms form fossil fuels.

Carbon Cycle

Oxygen Cycle• Oxygen is added to the atmosphere by the following:

– Photosynthesis - From aquatic and terrestrial organisms

• Oxygen is removed from the atmosphere:

– Respiration - From ALL organisms, aquatic and terrestrial

– Decomposition – Oxygen is needed to allow this process to continue

– Combustion – Oxygen is required to fuel the fire!

• Oxygen is also found in organic compounds in living things:

– Carbohydrates

– Lipids (Fats)

– Proteins

Oxygen Cycle

Nitrogen Cycle• All life requires nitrogen-compounds like amino acids, proteins & nucleic acids. • The majority of nitrogen, 79%, is supplied by the air, but the nitrogen in the air is not a usable form for most

organisms.

• Nitrogen fixation = process of bacteria converting nitrogen gas (N2) into usable nitrogen compounds. Usable forms of nitrogen include:

– Nitrates (NO3-)

– Nitrites (NO2-)

– Ammonia (NH3)• Different types of bacteria help us convert nitrogen into different forms:

– Nitrification = converts ammonia into nitrites OR nitrites into nitrates– Denitrification = converts nitrates back into nitrogen gas

• Plants get usable nitrogen compounds from nitrogen fixing bacteria. Animals get their nitrogen by consuming plants.• Decomposing plant and animal matter supplies a source of nitrogen. • Animal waste also provided a source of nitrogen.

Nitrogen fixing bacteria forming root nodules on legumes.

Nitrogen Cycle

Nitrogen Gas Ammonia Nitrates/Nitrites Nitrogen Gas A B C

A = Nitrogen Fixation B = Nitrification C = Denitrification

Ecological Limiting Factors & Natural and Human

Disturbances

BIO.B.4.2.4 Describe how ecosystems change in response to natural and human disturbances (eg., climate changes, introduction

of nonnative species, pollution, fires)BIO. B.4.2.5 Describe the effects of limiting factors on population

dynamics and potential species extinction.

Ecological Change

Natural disturbances• Climate changes• Natural disasters

Human disturbances• Fires• Pollution • Introduction of nonnative

(introduced) species• Urbanization• Deforestation

Disturbances may result in: Succession

Global warming Disruption of stable ecosystems

Succession

• Succession = A series of predictable and orderly changes within an ecosystem over time.

• Two types of succession:• Primary succession – succession in a previously

uninhabited area (new ecosystem developing)• Secondary succession – succession in a

previously inhabited area (damaged ecosystem recuperating - due to fire or natural disasters)

During which type of succession does it take more

time to reach a climax community?

Succession Terminology• Pioneer species - a group of hardy organisms, such as

moss and lichens, found in the primary stage of succession and that begin an area's soil-building process.

• Climax community - stable, end stage of ecological succession in which the plants and animals of a community use resources efficiently and balance is maintained.

Primary Succession

• New area; Never inhabited (Areas near glacier fields, erupted volcanoes, strip mines)

– New rock

– Lichens and mosses (Pioneer community)

– Bushes and shrubs

– Small trees and grass

– Large trees

– Hardwoods (Climax community)

Secondary Succession

Pre-existing community (Forest after a fire)

•Crabgrass•Tall grasses/plants•Pine trees sprout•Pine forest•Hardwoods (Climax Community)

Lake Succession• Eutrophication can lead to lake

succession! The following occurs:– Increase in nutrients leads to

algal blooms– Oxygen depletion– Aquatic life decreases– Fills in with sediment– Wetland/swamp forms– Spruce or fir forest forms

Limiting Factors• Limiting factors: Ecological factors that limit population growth. They

include:– Competition (Resource Availability – food, water, etc…)– Predation (Predator/Prey relationships)– Parasitism– Disease– Unusual weather– Immigration vs. Emigration– Births vs. Deaths– Natural disasters (volcanoes, tsunamis, tornadoes and hurricanes)– Human activities (urbanization, introduction of non-native species,

deforestation, etc…)

Effects of Limiting Factors• Limiting factors can cause ecosystems to reach carrying capacity or

threaten a populations existence. Carrying Capacity: The maximum amount of a particular species that

an environment can support. Threatened Species: A populations numbers are declining. Endangered Species: A populations numbers are very low. Extinct Species: All organisms of a particular species have died.