Principles of Ecology

Biology

What is Ecology?

– What is the lowest level of organization that most ecologists study?

– What name is given to several organisms in the same species interacting together?

– What factors are included in an ecosystem that are not included in a community?

– Describe how ecosystems and biomes differ? – Which level of biological organization is the

most complex?

What is Ecology?

– What is the lowest level of organization that most ecologists study? organism

– What name is given to several organisms in the same species interacting together? population

– What factors are included in an ecosystem that are not included in a community? Abiotic factors

– Describe how ecosystems and biomes differ? Biomes include several ecosystems over a large area.

– Which level of biological organization is the most complex? Biosphere

Levels of Organization

• Ecologist study organisms ranging from the various levels of organization:– Species– Population– Community– Ecosystem– Biome– Biosphere

Interrelationships

• Define the 3 categories of symbiosis and give an example of each – and record in your journal/notebook

• What is competition? Give an example.• What is predation? Give an example

Population – group of individuals of the same speciesliving in the same area, potentially interacting

Community – group of populations of different speciesliving in the same area, potentially interacting

What are some ecological interactions?

Why are ecological interactions important?

Interactions can affect distribution and abundance.

Interactions can influence evolution.

Think about how the following interactions can affectdistribution, abundance, and evolution.

Types of ecological interactions

competition

predation

parasitism

mutualism

commensalism

symbiosis

Competition – two species share a requirement for alimited resource reduces fitness of one or both species

Predation – one species feeds on another enhancesfitness of predator but reduces fitness of prey

herbivory is a form ofpredation

Parasitism – one species feeds on another enhancesfitness of parasite but reduces fitness of host

Mutualism – two species provide resources or servicesto each other enhances fitness of both species

Commensalism – one species receives a benefit fromanother species enhances fitness of one species; noeffect on fitness of the other species

Symbiosis – two species live together can includeparasitism, mutualism, and commensalism

Organizing ecological interactions

effect on species 1

effect onspecies 2

+ 0 -

+

0

-

mutualism

predationherbivoryparasitism

predationherbivoryparasitism

commensalism

commensalism

competition

competition

competition

Ecosystem Interactions

• What is a habitat?

• What is a niche?

Flow of Energy in an Ecosystem

• What are: autotrophs, heterotrophs, herbivore, carnivore, omnivores, detritivores

• What is the main energy source for life? • What is a trophic level? • How do you draw a food chain, food web?

What is the difference?• What group is at the top of the pyramid of

energy, biomass, numbers?

How does Energy flow through an Ecosystem?

• Energy flows through an ecosystem in ONE direction, – sun or chemicals

– Autotrophs

– heterotrophs

Energy Flow in Ecosystems:

Feeding Relationships

• Food Chain – steps of organisms transferring energy by eating & being eaten

• Food Web – network of all the food chains in an ecosystem

Food Web

Ecological Pyramids

Energy Pyramid

Biomass Pyramid

Pyramid of Numbers

• Trophic Level – each step in a food chain or food web

How does Matter move through an ecosystem?

• Unlike the one way flow of energy, matter is recycled within & between ecosystems

• Nutrients are passed between organisms & the environment through biogeochemical cycles

• Biogeochemical Cycles:– Bio –life– Geo – Earth– Chemo – chemical

1. WATER CYCLE

2. NUTRIENT CYCLES:

a) CARBON CYCLE

b) NITROGEN CYCLE

c) PHOSPHORUS CYCLE

Why are nutrients important ?

95% of your body is made of…1) OXYGEN

2) CARBON

3) HYDROGEN

4) NITROGEN

• Every living organism needs nutrients to build tissues and carry out essential life functions.

THE WATER CYCLE

Water Cycle 1

• Water – enters atmosphere by evaporation, transpiration – leaves atmosphere as precipitation

• Water on land– filters through ground– runs off to lakes, rivers, ocean

Water Cycle 2

• Aquifers – underground caverns, porous layers of rock– store groundwater

• Runoff – movement of surface water from land to

ocean

CARBON CYCLE (see fig.3-13)

4 PROCESSES MOVE CARBON THROUGH ITS CYCLE:

1) Biological

2) Geochemical

3) Mixed biochemical

4) Human Activity

CO2

CO2

Carbon Cycle

• CO2 gas enters plants, algae, cyanobacteria

– photosynthesis turns CO2 into organic molecules

• Cellular respiration, combustion, erosion of limestone return CO2 to water, atmosphere

– where it is again available to producers

NITROGEN CYCLE (see fig.3-14)

Nitrogen-containing nutrients in the biosphere include:

1) Ammonia (NH3)

2) Nitrate (NO3-)

3) Nitrite (NO2-)

ORGANISMS NEED NITROGEN TO MAKE

AMINO ACIDS FOR BUILDING PROTEINS!!!

N2 in Atmosphere

NH3

N03- &

N02-

Nitrogen Cycle 1

• Nitrogen fixation – conversion of nitrogen gas to ammonia

• Nitrification – conversion of ammonia or ammonium to nitrate

Nitrogen Cycle 2

• Assimilation – conversion of nitrates, ammonia, or ammonium

to proteins, chlorophyll, or nitrogen-containing compounds (by plants)

– conversion of plant proteins into animal proteins

Nitrogen Fixation

PHOSPHORUS CYCLE (see fig.3-15)

PHOSPHORUS FORMS PART OF IMPORTANT LIFE-SUSTAINING MOLECULES (ex. DNA & RNA)

Phosphorus Cycle 1

• Phosphorus erodes from rock

• Plants absorb inorganic phosphate from soil (through roots)

• Animals obtain phosphorus from their diets

Phosphorus Cycle 2

• Decomposers release inorganic phosphate into environment

• Phosphorus washes into ocean– is deposited in seabeds– lost from biological cycles for millions of years