Ecological Organization

Intro to Enviro Expo Part 1

Key Concepts…From way back in Biology:

• interactions within and among populations • nutrient cycling with energy flow through

ecosystems;• the effects of natural events and human

activities on ecosystems; and• analysis of the flora, fauna, and

microorganisms of Virginia ecosystems including the Chesapeake Bay and its tributaries.

What is ecology?

•The scientific study of interactions between organisms and their environments, focusing on energy transfer

•It is a science of relationships.

What do you mean by environment?

The environment is made up of two factors:

Biotic factors- all living organisms inhabiting the Earth

Abiotic factors- nonliving parts of the environment (i.e. temperature, soil, light, moisture, air currents)

Organism

Population

Community

Biosphere

Ecosystem

Think of it as a

hierarchy, a way of

organizing &

breaking

ecology/environment

down into smaller

sections

Ecological Organization

Organism- any unicellular or multicellular form exhibiting all of the characteristics of life, an individual.

•The lowest level of organization

Population-a group of organisms of one species living in the same place at the same time that interbreed and compete with each other for resources (ex. food, mates, shelter)

Community- several interacting populations that inhabit a common environment and are interdependent.

Ecosystem- populations in a community and the abiotic factors with which they interact (ex. marine, terrestrial)

Biosphere- life supporting portions of Earth composed of air, land, fresh water, and salt water.

•The highest level of organization

YOUR TASK:Either on your own or with a partner (and if you work with a partner your end product better show that 2 people put work into it!), come up with a way to physically represent these relationships (community, population, organism, etc). You may use common everyday items, that you carry with you or are located in the classroom.

Ecology – Part 2

Relationships

• Spatial

• Feeding

• Symbiotic

“The ecological niche of an organism depends not only on where it lives but also on what it does. By analogy, it may be said that the habitat is the organism's „address‟, and the niche is its „profession‟, biologically speaking.”

Odum - Fundamentals of Ecology

Spatial RelationshipsHabitat vs. Niche

Niche - the role a species plays in a community (job)

Habitat- the place in which an organism lives out its life (address)

Habitat vs. Niche cont…

A niche is determined by the

tolerance limitations of an organism

(limiting factor)

Limiting factor- any biotic or abiotic

factor that restricts the existence of

organisms in a specific environment.

Examples of limiting factors-

•Amount of water•Amount of food•Temperature

Habitat vs. Niche

Feeding Relationships

• There are 3 main types of feeding relationships

1. Producer- Consumer

2. Predator- Prey

3. Parasite- Host

Feeding Relationships

Producer-

–all autotrophs (plants)

– trap energy from the

sun

–bottom of the food

chain

Feeding Relationships

Consumer-- all heterotrophs

– they ingest food containing the sun’s

energy

• Herbivores – eats plants, primary consumers, prey animals

• Carnivores – eat meat, predators, hunt prey for food

• Omnivores – eat both plants and animals

• Decomposers – feed on dead organisms (variety of kinds)

Feeding Relationships

Consumer-

Herbivores

• Eat plants

• Primary consumers

• Prey animals

Feeding Relationships

Consumer-

Carnivores

• eat meat

• Predators

– Hunt prey

animals for food.

Feeding Relationships

Consumer-

• Scavengers– Feed on carrion,

dead animals… which

makes them carnivores

– Can be just about

any kind of animal

Feeding Relationships

Consumer-Omnivores

-eat both plantsand animals

Feeding Relationships

Consumer-Decomposers– Breakdown complex

compounds into simpler

molecules that can be

absorbed back into the

soil

– Majority are

microscopic and

bacterial in nature

Feeding Relationships

Food chain- simple model that shows how matter and energy move through an ecosystem

Feeding Relationships

Food web- shows all possible feeding relationships in a community at each trophic level

• Represents a network of interconnected food chains

Food chain Food web(just 1 path of energy) (all possible energy paths)

Trophic Levels

• Each link in a food chain is known as a trophic level.

• Trophic levels represent a feeding step in the transfer of energy and matter in an ecosystem.

• Can be producers, 1st consumer, 2nd consumer, 3rd consumer (etc.)

Trophic Levels

Biomass- the amount of organic matter comprising a group of organisms in a habitat.

• As you move up a food chain, both available energy and biomass decrease.

• Energy is transferred upwards but is diminished with each transfer.– Only about 10% is transferred

Trophic Levels

Producers- Autotrophs

Primary consumers- Herbivores

Secondary consumers-small carnivores

Tertiary consumers- top

carnivores

E

N

E

R

G

Y

Toxins in food chains-

While energy decreases as it moves up the food chain, toxins increase in potency.

•This is called biological magnification

Ex: DDT & Bald Eagles,

Mercury in fish (shark, king

mackerel, swordfish and tilefish are

high in mercury)

Symbiotic Relationships

Symbiosis- two species living together

3 Types of symbiosis:

1. Commensalism

2. Parasitism

3. Mutualism

Symbiotic Relationships

1. Commensalism-

one species benefits and the other is neither harmed nor helped

Ex. orchids on a tree

Epiphytes: A plant, such as a tropical orchid or a bromeliad, that grows on another plant upon which it depends for mechanical support but not for nutrients. Also called aerophyte, air plant.

Symbiotic Relationships

2. Parasitism-

one species benefits (parasite) and the other is harmed (host)

• Parasite-Host relationship

Example: tick on a deer, leeches, fleas,tapeworm

Symbiotic Relationships

3. Mutualism-beneficial to both species

Ex. cleaning birds and cleaner shrimp

Symbiotic Relationships

3. Mutualism (cont.) beneficial to both species

Ex. lichen

Type of relationship

Species harmed

Species benefits

Species neutral

Commensalism

Parasitism

Mutualism

= 1 species

Biogeochemical Cycles

Intro to Enviro Expo Part 3

Nutrient Cycles

Cycling maintains homeostasis (balance) in the environment.

•3 cycles to investigate:

1. Water cycle

2. Carbon cycle

3. Nitrogen cycle

Water cycle-

•Evaporation, transpiration, condensation, precipitation,

condensation, infiltration/percolation, runoff

Water cycle-

Carbon cycle-

•Photosynthesis and respiration cycle carbon and oxygen through

the environment.

Carbon/Oxygen Cycle~ Photosynthesis and respiration cycle

carbon and oxygen through the environment.

O2

CO2

Carbon cycle-

Carbon Cycle

• In fact, carbon constitutes the very

definition of life

– Its presence or absence helps define whether a

molecule is considered to be organic or

inorganic.

• Every organism on Earth needs carbon

either for structure, energy, or, as in the case

of humans, for both.

Carbon Cycle

• Carbon is found in forms as diverse as:

– GAS

• carbon dioxide (CO2)

– SOLIDS

• limestone (CaCO3)

• Wood

• Plastic

• Diamonds

• Plants

• Graphite

Carbon Cycle

• ON LAND - the major exchange of carbon with the atmosphere results from:

– Photosynthesis and

– respiration

Carbon Cycle

ON LAND - the major exchange of carbon with the

atmosphere results from

– During daytime in the growing season, leaves absorb sunlight and take up carbon dioxide from the atmosphere (photosynthesis).

– At the same time plants, animals, and soil microbes consume the carbon in organic matter and return carbon dioxide to the atmosphere (respiration).

Carbon CycleSo can the amount of carbon in the

atmosphere change?

Yes!During winter for instance, there are hardly any leaves

on the trees, so photosynthesis decreases, thus the amount of

CO2 being taken in by these leaves is decreased.

BUT…

At the same time animals are still respiring/exhaling the same

amount of CO2 that they were in all the other seasons

SO…

The amount of CO2 in the atmosphere during winter has

_____________________.increased

Carbon Cycle

So can the amount of carbon in the atmosphere change?

http://www.bbc.co.uk/cumbria/content/images/2007/02/06/winter_trees_

470x353.jpg http://www.craiglauder.com/gallery/Limberlost/images/SUmmer_Trees_Lake.jpg

So an increase in CO2 in atmosphere during winter

in our Northern Hemisphere

Nitrogen cycle-

All organisms need N to build proteins (which are used to build new cells).

Atmospheric nitrogen (N2) makes up nearly 78%-80% of air.

Organisms can not use it in that form.

Lightning and bacteria convert nitrogen into usable forms.

Nitrogen cycle-

Only certain bacteria and industrial technologies can fix nitrogen.

Nitrogen fixation-convert atmospheric nitrogen (N2) into ammonium (NH4

+) which can be used to make organic compounds like amino acids.

N2 NH4+

Nitrogen cycle-

Nitrogen-fixing bacteria:

Some live in a symbiotic relationship with plants of the legume family (e.g., soybeans, clover, peanuts).

Nitrogen cycle-

• Decomposers help by breaking up storedNitrogen (in wastes, leaves, decaying plants/animals) and putting Nitrogen back into the soil

– Then bacteria in the soil turn a small portion into Nitrogen gas and returns it to the atmosphere – so that completes the cycle.

http://www.tokyomango.com/tokyo_mango/images/2007/10/0

5/super_mushroom.jpg

Nitrogen cycle-

•Some nitrogen-fixing bacteria live free in the soil.

•Nitrogen-fixing cyanobacteria are essential to maintaining the fertility of semi-aquatic environments like rice paddies.

Unicellular nitrogen-fixing

cyanobacteria, shown in this

light micrograph, play an

important role in the oceanic

nitrogen cycle. (Credit: Washington

University in St. Louis)

Atmospheric nitrogenLightning

Nitrogen fixing bacteria

Ammonium Nitrification by bacteria

Nitrites Nitrates

Denitrification by bacteria

Plants

Animals

Decomposers

Nitrogen Cycle

Phosphorus cycle-

• Essential to form bones and teeth in animals,

also helps increase growth in plants

• Phosphorus cycle moves from the

environment to organisms, then back to

environment again. (so doesn’t really cycle through

the atmosphere)

http://www.gonzaga.edu/campus+resources/sustainability/Images/waterfall_

web_environment.jpghttp://whyfiles.org/shorties/147tooth/images/teeth.jpg

Phosphorus cycle-

• Enters soil when rocks erode or when

decomposers break down the remains of

dead plants and animals

• Plants then absorb phosphorus through their

roots and the cycle is complete.

How do Humans Affect the Nitrogen and

Phosphorus Cycles?

• Humans have increased the natural rate of

nitrogen and phosphorus, through the use of

chemical fertilizers.

- When excess nitrogen and phosphorus compounds

run off fields into bodies of water, they can cause an

overgrowth of algae blooms and aquatic plants.

- If abundance of aquatic plants, then

abundance of plant decay and abundance of decomposer, which

deplete oxygen that other aquatic organisms need to survive.

Algal Blooms

http://media.supereco.com/media/2009/02/02/320w/algae-bloom.jpg

http://www.waterencyclopedia.com/images/wsci_01_img0017.jpg

http://serc.carleton.edu/images/microbelife/topics/red_tide_genera.v3.jpg