ecology & the flow of energy in the ecosystem. the study of the interactions of organisms with...

Ecology & the Flow of Energy in the Ecosystem

The study of the interactions of organisms with one another and their physical environment

Ecology

EcosystemA self-sustaining

collection of organisms and their physical environment

Both biotic and abiotic factors in a large area

Biotic & Abiotic Factors

Biotic =Living

organisms

Abiotic =NonlivingSoil,Air,Water

Energy in Ecosystems

Energy flows into the biological world from the SUN, the ultimate source of all energy.

Producers Producers are

autotrophs… they can make their own food through photosynthesis

Plants, some bacteria and algae

Consumers

Eat other organisms to obtain energy

Example: cows, humans…

Detrivores Organisms that

obtain energy by eating organic wastes or dead bodies.

Ex. Vultures

•http://www.slivoski.com/birding/birds/turkeyvulture.htm

•http://montereybay.com/creagrus/vultures.html

Decomposers Break down organic wastes

(feces, urine, dead leaves or bodies) and cause decay.

Receive energy from every other type

Responsible for the final step in the food chain

Example:Earthworms, maggots, fungi, and some bacteria

How is energy passed along an ecosystem?

Pyramid of Energy

Trophic Levels: Movement of energy

through an ecosystem Levels of energy away

from the sun (ulitmate source of energy)

Who eats who in the food chain

Shown as food chains, webs & pyramids

3rd Trophic Level – animals that feed on plant eaters or other flesh eaters (carnivores) Ex - Tiger

- omnivores eat both plants & animals. Ex - humans

2nd Trophic Level – animals that eat plants (herbivores) Ex - cow

1st Trophic Level – producers/autotrophs Ex - plants

Food Pyramid

On average, only 10% of the energy in any trophic level will be transferred to the next level.

Food Pyramid

Tertiary consumer

Secondary consumer

Primary consumer

Producers

Food Chains & Food Webs

Most animals feed on more than one trophic level and feed on several different species at each trophic level. Making up a food chain and eventually a food web.

Food Chain

ONLY ONE source of food

Less stable

Food WebMore than one

choice of foodSeveral food

chains linked together

More stableMore Common

PopulationEcology

PopulationNumber of

IndividualsSame SpeciesLive together

in one area or place

What dynamics might be involved in predicting population growth?

Population Size Population Growth Rate Carrying CapacityLimiting Factors

Population SizeNumber of

individuals in a population

Growth occurs when the birthrate is greater than the death rate.

Population Growth CurvesExponentialgrowth: Population

increases by a constant proportion per unit of time

At this growth rate the population exhibits a J-shaped curve

Population Growth CurvesLogistic growth: Population increases

rapidly for a period of time, its growth begins to slow, and ultimately, growth stops.

At this growth rate the population exhibits an S-shaped curve.

K (carrying capacity) = maximum population size that an environment can support

K

Factors That Control Population Growth

Populations don’t grow indefinitely because of Limiting factors.

Limiting Factors: Competition Predation Parasitism Crowding Stress Disease

Competition Situation in which

two or more organisms attempt to use the same scarce resource (this could be a food source, a good location for capturing sunlight by plants, a particular nutrient, etc…)

Predation A relationship between two organisms in

which one organism (predator) kills and devours another organism (prey).

Parasitism: The relationship

between two organisms where one organism benefits (parasite) and the other is harmed (host).

Example: Tapeworm You are harmed

because it lives off your intestinal fluids

Segments break off to form a new worm!

Biodiversity The number

of species living within an ecosystem.

How Populations Evolve

Hardy-Weinberg Principle

–The frequencies of alleles in a population do not change unless evolutionary forces act on the population.

–p2 + 2pq + q2 = 1

How Biodiversity Impacts Population Growth

6 forces that cause populations to evolve:

Mutation – ultimate source of all variation Migration – movement of organisms from one

population to another, creates gene flow. Nonrandom mating – when individuals prefer to

mate with others of their own genotype, inbreeding is an example.

Genetic drift – random change in response to their environment.

Natural selection –Survival of the fittest. Extinction- species that have disappeared

permanently.

Organism Interrelationships

Organism Interrelationships: Symbiosis=

a close long term relationship between two or more species

Beneficial: Mutualism=

Both benefit Commensalism=

Only one benefits & other is not harmed or helped

Harmful: Parasitism=

One benefits &

Host slowly harmed

Fungi carbon dioxide moisture

Algae food Oxygen

Mutualism (Both Benefit)

Commensalism

(One Benefits)

Whale unharmedBarnacles Protection from

predators Transportation to

new food sources

Commensalism (One Benefits)

Clown fish dwell among the tentacles of tropical sea anemones. The anemomes are capable of stinging most fishes, but the clown fish possess a special mucous coating that somehow prevents the discharge of the anemone's stinging cells. The fish is protected from predators by the stinging cells.

Parasitism: The

relationship between two organisms where one organism benefits (parasite) and the other is harmed (host).

Example: Tapeworm You are harmed

because it lives off your intestinal fluids

Segments break off to form a new worm!

Cycles

Cycles within Ecosystems Almost everything

within an ecosystem is recycled.

Water, carbon, nitrogen & phosphorus pass from the nonliving environment to living organisms & then back to the environment.

Water Cycle Water is the most

important, non-living component of the ecosystem.

Nonliving cycle: involves condensation, precipitation, & evaporation.

Living cycle: involves plants in a process called transpiration.

Human Impact on the Environment

Human Impact on the Environment

How much trash do you think you throw away?

How many times a day does a person pollute the environment?

How many lakes and forests are killed by acid rain?

Pollution

Pollution is anything potentially harmful that humans add to the environment.

Pollution can drastically damage the health of ecosystems as well as the health of human beings.

Air Pollution

Mainly caused by the burning of fossil fuels.

Many forms:

- Carbon Monoxide

- Nitrogen Oxide

The Ozone Layer Consists of a layer of gas that is

responsible for keeping UV radiation from reaching the earth’s surface.

It is being destroyed by chlorofluorocarbons (CFC’s)

CFC’s found in coolant in refrigerators & air conditioners, and the propellant in aerosol cans.

1 chlorine molecule destroys 100,000 ozone molecules.

The Ozone Layer

Acid Rain Occurs when air

pollutants get mixed with rain in the atmosphere.

The product is sulfuric acid which is falls back to earth in rain and snow.

Pure water has a pH of 7.0 (neutral)

Normal rain has a pH of about 5.6. Acid rain has a pH below the 5.6 Avg. The pH in northeast US is 3.8.

Marble surfaces exposed to acid rain develop a rough "sugary" texture because the calcite grains are loosened as the edges dissolve in the rain water. Column capital volute, Jefferson Memorial, Washington, D.C.

Acid Rain and Our Nation’s Capital

Acid Rain

NaOH

Greenhouse Effect

Caused when sunlight reflected from earth’s surface is trapped as heat by carbon dioxide gas.

Scientists predict an average temperature increase of 1-5 degrees C by 2050.

How does this impact the environment?

ResourcesRenewable resources: Resources that

replenish themselves naturally.

Example:– Trees

Nonrenewable resources: Resources that do not

replenish themselves naturally.

Examples:– Extinct species– Fossil fuels such as oil

and gas

Trees are a renewable resource, but a forest ecosystem is nonrenewable. Why?

New trees can be planted and grown to replace those cut down, but an ecosystem involves a complex web of relationships that are established over very long periods of time.

How pollution effects our Resources

Pollution has led to a rapid draining of fuel supplies.

The known reserves of oil and natural gas will be nearly depleted by the middle of the next century.

Fossil fuels are nonrenewable resources. Nonrenewable resources do not replenish

themselves naturally, whereas renewable resources do.

Solutions to Pollution Reduce pollution by

proper waste disposal and recycling

Conserve nonrenewable resources

Reduce consumption of natural resources

Conserve energy Curbing human

population growth

Waste disposal & Recycling Each year,

Americans generate 153 million tons of garbage. This is dumped into landfills or is burned creating air pollution.

Solutions: Recycle as much as

possible– Aluminum products– Glass containers– Office & school paper– Newspaper– Many plastic materials

Buy products that contain recycled materials

Properly dispose of toxic and hazardous materials– Household insecticides– Oven cleaners– Furniture cleaners– Oil-based paint– Motor batteries & oil

Conserving Nonrenewable Resources

Topsoil for Agriculture The world has lost ¼ of its topsoil due to erosion from clearing of trees and vegetation and cultivating crops.

Ground water (water trapped beneath the soil) Groundwater is being depleted by watering lawns, washing cars, and running fountains. It is also being polluted by poor disposal of chemical wastes.

Species are disappearing. About 1/2 of the world’s tropical rainforests have been destroyed. At this rate, most of the world’s rainforests will be gone in 40 years. It is estimated that 1/5 or more of the world’s species will become extinct, mope than a million species lost, if the rainforests are destroyed.