ecology

ECOLOGY

Ecological Organization

• Abiotic factor: Non-living things in an ecosystem that affect the life of the organism. – Sunlight– Air– Water– Temperature

• Biotic factor: All living things in an ecosystem. – Animals– Plants– Bacteria– Fungi

FACTORS AFFECTING POPULATION SIZE

Biogeochemical Cycling

Competition• When 2 or more species live in the same

area and eat the same organisms they are said to be in competition for those resources.

• Examples:– Cheetas and lions have the same prey on the

savannah in Africa– Grass and weeds in your yard

Coexistence/Cooperation• When individuals of different species

work together to meet their needs they are said to be coexisting or cooperating.

• There are several strategies that species use to cooperate:– Mutualism– Parasitism– Commensalism

Mutualism• An interspecies relationship in which

both species benefit from the interaction.• Species 1 (+)• Species 2 (+)• Examples:

– A bee pollinating a flower– Fungus on plant roots– Clown fish and sea anemone

Parasitism• An interspecies relationship in which one

species benefits to the detriment (harm) of another.

• Host - Species 1 (-)• Parasite - Species 2 (+)• Examples:

– Fleas/ticks on a dog– Tape worm– Head lice

Commensalism• An interspecies relationship in which one

species benefits and the other is unaffected.

• Species 1 (+)• Species 2 (0)• Examples:

– Barnacles on a whale– Cattle egrets and livestock– Orchids on a tree

PRODUCERSEnergy mostly enters to the world as sunlight and producers capture it to turn it into food molecules in a process called photosynthesis.

They are: plants, algaes and bacteria.

Producers are the source of all the food in an ecosystem

A producer can make its own food

• Consumers cannot make their own food.• Consumers obtain energy by feeding on (consuming) other organisms.• They are classified by what they eat:

– Herbivores– Carnivores– Omnivores

CONSUMERS

HerbivoresDo they eat “ Potatoes ” ? ? ? ?

PRIMARY CONSUMERS• Also known as HERBIVORES • Ex: mice, deer, cows, and elephants• Herbivores eat ONLY PLANTS

• Are CARNIVORES or OMNIVORES• If the animal must be killed before it is

eaten, the secondary consumer is known as a predator.

SECONDARY CONSUMERS

ScavengersFeed on the bodies of dead organisms

DECOMPOSERSBreak down wastes and dead organisms, and so complete the cycle by: - returning nutrients to the soil & water - returning CO2 to the air & water

Food Chain

A food chain shows how each living thing gets food, and how nutrients and energy are passed from creature to creature. 

Food Webs

A food web consists of all the food chains in a single ecosystem.

Trophic Levels An organism’s position in the food chain is

often referred to as its trophic level.

Energy Pyramids• 90% of energy at each level is used by the

organism for its day to day existence.• So only 10% transfers to the next level

There are as many as 25 elements found in ALL living organisms and just like energy they are cycled through the biosphere. Far and away the most abundant are CHNOPS.

Carbon Cycle

Plants capture energy from Plants capture energy from sunlight for Photosynthesissunlight for Photosynthesis

6CO6CO22+ 6H+ 6H22O + Energy O + Energy C C66HH1212OO66+ + 6O6O22

Photosynthesis occurs in the Photosynthesis occurs in the chloroplasts in plant cellschloroplasts in plant cells

Cellular Respiration

O2 is converted to CO2 in the mitochondria of animal cells.

CC66HH1212OO66+ 6O+ 6O22 6CO 6CO22+ 6H+ 6H22O+ Energy O+ Energy ((infraredinfrared))

Combustion

Any chemical reaction in which one of the reactants is OXYGEN (aka fire) is a combustion reaction.

COMBUSTION OF CARBON• A combustion reaction in which one of the reactants is

CARBON always yields CO2 as a product.

• Burning Methane CH4 + O2 CO2 + 2H2O

• Burning Propane: C3H8+5O23CO2+4H2O • Examples:– Incinerating trash, yard waste– Forest fires– Combustion engines in cars– Burning coal to generate electricity

Just like tree rings can tell us about how old the tree is and whether it was a wet/dry or cold/hot year…

So can Ice Core Samples tell us about the paleoclimate…

Paleo = ancient

The Ice Core Drill

Layers of Ice

Like the growth rings on a tree…each layer represents a year (or in this case, season) of ice accumulation.

Volcanic Ash Layer

Cutting the Ice

Gases Dissolved in the Ice

Ice Core Storage Room

Climate Change• CO2 is a greenhouse gas, meaning that it

holds heat IN the atmosphere.• Atmospheric carbon has increased

dramatically since the beginning of the Industrial Revolution in 1850.

Effects of Climate Change• Melting Polar Sea Ice • Change in ocean salinity• Ocean Acidification• Rising global temperatures• Rising sea levels• Receding glaciers• ALL ecosystems are affected!

Melting Polar Sea Ice

Ocean Acidification• Ocean acidification is a reduction in

surface ocean pH levels due to the increasing absorption of carbon dioxide. 

• When CO2 dissolves in water, carbonic acid is formed.  

• The saturation of carbonic acid decreases the ability of many marine organisms to build and maintain their shells and skeletal structures. 

Ocean Acidification

Results in habitat loss & breakdown of the marine food web

Mendenhall Glacier

The Meade Glacier is located:

Here he is from space (zoomed)

Here he is on approach when we helicoptered out to visit him last summer:

Receding Glaciers

Water Cycle• ALL living organisms MUST have water to survive!• The availability of water is determined by the water

cycle and weather patterns driven by it.• Water is a reactant in photosynthesis and a product

in cellular respiration!

The Nitrogen Cycle• Nitrogen-fixing bacteria – “Fix” nitrogen

from the atmosphere into a form that is ingestible by living organisms.

• Nitrogen moves through the food chain (trophic layers) in the same manner energy does.

• Denitrifying bacteria – break down decomposing organic material and release the nitrogen back into the atmosphere restarting the cycle.

PHOSPHORUS CYCLE

Field Study: Wild Horses of Shackleford Banks

This is my tent. It is upside down. The wind did it. What does that tell you about the wind on the island?

This young fella is standing in freshwater.