Ecology Branch of Biology; study of organisms’ relationships with one another and their environment.

Organism

Population

Community

Ecosystem

Biosphere

All living organisms in an area plus the nonliving things around them

Biome

Single individual

A group of individuals (same species) living together

Different populations (different species) living together

All parts of Earth that support life

Group of ecosystems with similar climate

Biotic Abiotic

Living things

ex: animals, plants, bacteria, etc.

Non-living things

ex: moisture, temperature, air currents, light, etc.

Habitat – area where a particular species lives

Niche – A species’ role in its environment. Includes its habitat plus what it eats and how it affects its environment.

Secondary Consumers – organisms that eat primary consumers.

Autotrophs or Heterotrophs?

Omnivores – organisms that are adapted to eat plants and meat.

Carnivores – organisms that are adapted to eat meat.

Energy Transfer

What is this diagram called?

Arrows point in the direction of energy transfer.

Energy goes from the grass, to the deer, to the bear…

What happens to the Bear’s energy? Recycled into the environment.

Scavengers – get their energy from eating the corpses of dead organisms, speeding up decomposition. (crows, vultures, raccoons)

Decomposers – get their energy from breaking down decaying organisms (more molecular level) . (bacteria, fungi, worms)

Energy Transfer

Grass Deer Bear FOOD CHAIN

Energy Pyramids are separated into trophic levels.

Energy Pyramid

Producers

Primary Consumers

Secondary Consumers

Tertiary Consumers

Trop

hic L

evel

1st

2nd

3rd

4th

Grass Deer Bear They obtain energy from all trophic levels!

What about scavengersand decomposers?

Food chain:

Plants Grasshoppers Mice Owls

Energy Pyramid

Plants

Grasshoppers

Mice

Owls

100 %

10 %

1 %

.1 %

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$100

$.10

$1

$10

Scavengers &

Decomposers

Don’t forget

about the

Most food chains consist of only 2-4 energy transfers.

Why? The amount of energy available for transfer is a small portion of what was available at the first transfer.

Plants Grasshoppers Mice Owls

Are food chains an accurate representation of energy transfer in an ecosystem? NO

Why not? Consumers eat more than one type of food and there are multiple producers.

Food Chains

A food web shows the possible feeding relationships in a community.

How many different food chains can you identify?

Is it possible to determine predator/prey relationships from a food chain or food web?

Predator – an organism that eats another

Prey – an organism that is eaten by another

Food Webs

Both species benefit

Leaf-cutter ants Fungus Bacteria

Do humans engage in mutualistic relationships with other species? Yes – bacteria in our intestines

Mutualism

One species benefits while the other is unaffected

The Spanish moss benefits from being high off the ground (away from herbivores) and closer to sunlight, but the oak trees are not affected.

Commensalism

One species benefits while the other is harmed

Tank – Mrs. Downey’s puppy Tick

Puppy harmed – itchy, ticks could also carry diseases.Tick happy – sucking poor puppy’s blood. =(

Parasitism

Is growth unlimited? No

If growth was unlimited, it would exhibit exponential growth – as the population gets larger, it grows faster. (unchecked population growth – infinite)

Exponential growth is often illustrated using a J-shape curve.2-4-8-16-32-64-128-256-512-1,024-2,048-4,096- 8,192-16,384-32,768-65,536-131,072-262,144- 524,288-1,048,576………. 20 Generations = 1million+ individuals

Population Growth Rate

Some bacteria – 15 minutes for next generation = 20 generations (1 million) in 5 hours

Populations cannot grow exponentially. Populations stabilize in an S-shaped growth curve.

The population will grow exponentially until it reaches a maximum at which point it will level off.

Population Growth Rate

Carrying Capacity

Logistic Growth

Carrying capacity – the number of individuals of any given species that the environment can support.

Both biotic and abiotic factors limit the carrying capacity for a species in an environment.

Food availability – lack of food can reduce population

Competition – for food or habitat

Carrying Capacity, Limiting Factors

Harsh weather – severe winter can significantly reduce the amount of food and space available

Drought – affects the amount of food available for ALL organisms

(how? – plants die, herbivores have less food – they die, secondary consumers have less food – they die, etc.)

Space/shelter – organisms require space to grow and shelter for protection

Limiting Factors, cont’d.

Other factors which affect population size are not dependent on density:

weathernatural disastershuman activities (cutting down forests, damming rivers, etc.)

Increased density can also have an effect on the ecosystem:rapid use of resourcespollution of air, water, land

Population

Human Population

Human Population

What is it?Increase in the average temperature of the biosphere.

Is it real?Yes – There is substantial data which points to the gradual increase in temperature.

Is it caused by humans?It is widely accepted that humans have some effect on global warming, but Earth’s climate has changed many times over its history – it is likely that the global warming we observe now is part of Earth’s natural cycle of climate change.

Global Warming

How are humans affecting global warming?Activities which release carbon dioxide and other greenhouse gases into the atmosphere (burning fossil fuels, burning and cutting forests)

According to data, carbon dioxide levels have been rising in the atmosphere for 200 years – added carbon dioxide intensifies the Earth’s natural greenhouse effect.

Greenhouse EffectEarth’s atmosphere is like a blanket.

Sun’s radiation reaches Earth, heats up the surface, and radiates back out. The atmosphere traps that heat.

Gases in the atmosphere (such as carbon dioxide and water vapor) help trap heat. More carbon dioxide = more trapped heat.

Global Warming A Climate Minute

Global Warming

Greenhouse Effect

CFCs (chlorofluorocarbons) – were used in aerosol cans, coolant, air conditioners, production of certain plastics. Today, most CFCs are banned in an effort to reduce the effect on the environment.

Environmental resources are used and otherwise affected by human activities.

What resources? Water, air, land, forestsHow do humans affect these resources?

Water pollutionAir pollutionDeforestationOverfishing

Resource Use

Deforestation is the loss of forests.What can happen??

- Severe soil erosion after heavy rains (nutrients washed away)- Grazing/plowing after deforestation can cause permanent

changes – trees cannot grow there again- Extinction of many different species of plants and animals

Why are forests cut down?Roads, buildings, farmland, etc.

Deforestation

Pesticide – kills pestsThese toxic compounds can accumulate in organisms.

DDT – cheap pesticide that was used to kill many insects. Two problems – non-biodegradable (is not broken down by bacteria, plants, or animals); once organisms have it in their system, they do not eliminate it.

Biological magnificationaka: bioaccumulation – occurs when the concentration of toxins increases in organisms at higher trophic levels

Pesticide Use

Nitrogen CycleNC is #2 in the country for number of hogs!Problem? Hog waste contains a lot of nitrogen which will runoff into rivers, streams, lakes, etc. High nitrate levels cause Pfiesteria – becomes deadly and kills fish.

Dutch Elm DiseaseFungal infection on trees that is spread by a beetle

Introduced to NC from Europe

Acid RainMain source of acid rain in NC: coal power plants releasing sulfurNC mountains are most severely affected

NC CoastsBeach erosion is increasing due to the amount of storms and development on the beach.

NC PiedmontUrban development leading to habitat destruction and water runoffRunoff contains fertilizers, brake fluid, other pollutants; causes algal blooms which kills fish and other aquatic life.

Invasive SpeciesKudzu introduced to help with stream bank erosionGrows 1 foot per day, roots can be 12 feet deep; will cover trees, signs, houses.

Nutrients cycle throughout the ecosystem (they are REcycled)

Nutrients are chemicals required for organisms to live.

Balance of water stays fairly constant over time.

Evaporation – water transforms from liquid to gas and is released into the atmosphere.

Condensation – water vapor transforms into liquid droplets, forming clouds and fog.

Precipitation – condensed water falls to the Earth’s surface as rain, snow, sleet, hail, etc.

Runoff – water movement across the land.

Transpiration – release of water vapor from plants.

Water changes form but it is RECYCLED.

Nutrients cycle throughout the ecosystem (they are recycled)

Nutrients are chemicals required for organisms to live.

Carbon Dioxide in the atmosphere – released via respiration, burning of fossil fuels.

Carbon stored in plants in carbohydrates (photosynthesis)

Carbon stored in soil, fossil fuels, found in decaying matter and waste

Carbon changes form but it is RECYCLED.

Nutrients cycle throughout the ecosystem (they are recycled)

Nutrients are chemicals required for organisms to live.

Most abundant element in the atmosphere.

Nitrogen-fixing bacteria convert atmospheric nitrogen into a form usable by plants.

Plants, animals, and decomposers produce ammonium

Nitrifying bacteria convert ammonium into a form usable by plants.

Nitrogen changes form but it is RECYCLED.

Nutrients cycle throughout the ecosystem (they are recycled)

Nutrients are chemicals required for organisms to live.

Phosphorus in several forms in soil, rocks, and minerals.

Plants use phosphorus from the soil as they grow.

Phosphorus returned to the soil via manure and dead bodies.

Does not cycle through the atmosphere – remains primarily as a solid.

Fertilizers contribute phosphorus to the soil.

Typically the limiting nutrient in ecosystems because it is lost in erosion and runoff.

Phosphorus changes form but it is RECYCLED.