Ecology Unit

What is Ecology?

the study of interactions between Ecology- the study of interactions between organisms and organisms organisms and their environment

Factors that effect us: 1. Abiotic Factors Moisture Wind/Air currents Light Temperature Soil

A- stands for non Bio- stands for living Abiotic Factors- nonliving factors

2. Biotic Factors:

Biotic- Living factors

What is the organization of Ecological Study? Organism Population Community Ecosystem Biosphere

Levels of Organization Organism- one individual living thing Ex an elk

Levels of Organization Population- all members of the same species that live in the same area Ex many elk

Levels of Organization Community- different populations in the same area Ex many groups of elk, beavers, trees, grass (all living)

Levels of Organization Ecosystem- all organisms in a particular area and the nonliving surroundings. Ex many groups of elk, beavers, trees, grass, rocks, water, mountains

Levels of Organization Biosphere- all of the planet where life exists. Includes land, water, and, air Life extends 8 km up and 11 km below the surface

A change in any biotic or a-biotic factor can lead to changes in all populations Ex. A severe drought may limit water supply. Some animals and plants may die as a result. Populations must be able to adapt to changes (become stronger) or they may be eliminated. The health of an ecosystem is determined by BIODIVERSITY (various types of organisms) of the ecosystem

POPULATIONS Carrying Capacity – maximum number of a species that an area can sustain Population size is affected by LIMITING FACTORS – anything that may cause a decrease in population EX. Food, shelter, space, other organisms

POPULATIONS Density-dependent factors – factor whose effect on a population varies with the density (crowding) of the population EX. Food – larger populations require more food, shelter. Disease spreads faster in more dense populations These generally are triggered in larger populations

POPULATIONS Density independent factors – factor that occurs regardless of the size of a population EX. Weather, pollution, natural disasters (fire)

POPULATIONS Abiotic factors can limit populations Ex. Not enough water, nitrogen, sunlight, salinity, pH, temperature Biotic factors can limit populations EX. Bacteria (cause disease)

IN AN ECOSYSTEM: Organisms live in a Habitat Organisms fit into a Niche of the environment

Habitat vs. Niche Habitat- an area where an organism lives (address) Niche- an organisms role in its environment (occupation)

Community Interactions when organisms live together in an ecological community they interact constantly. Interactions: Generate stability Limit populations Maintain balance of available resources

Community Interactions *Interactions help keep entire ecosystem stable - population growth/decline are predictable -resources increases/decreases are predictable -energy flows at a constant rate

COMPETITION Two organisms fighting for the same resource Less adapted organism usually looses Population will decline

Predation Predation- when an organism captures and feeds on another organism. Predator- hunter Prey- hunted

Symbiosis Symbiosis- any relationship where two species live closely together. (3 types) Mutualism Parasitism Commensalism If the population of either organism changes, it will affect the other

Symbiosis Mutualism- both species benefit from a relationship. Lichens (fungus and Algae) One example is the lichens, little non-descript patches of stuff you see growing on rocks and tree bark. This is a symbiosis, consisting of a fungus and an alga. The fungus provides a protective home for the algae, and gathers mineral nutrients from rainwater and from dissolving the rock underneath. The alga gathers energy from the sun. There are thousands of species of lichen in the world; actually thousands of species of fungi with just a few species of algae which can form a partnership with almost any of them.

Symbiosis Parasitism- One creature benefits and one creature is harmed Ex tapeworm. Feeds in a humans intestines absorbing his/her nutrients.

Commensalism One organism benefits, the other neither benefits or gets harmed EX. Shark and Remora fish Remora gets scraps and protection, shark gets nothing

Relationships: Symbiosis = Living Together a) commensalism b) mutualism c) parasitism

Identify these relationships

Energy Flow (Trophic Levels) Producers -make their own food (autotrophs) Consumers -get energy from consuming producers (heterotrophs)

Types of Consumers Herbivores- eat only plants Carnivores- eat animals Omnivores- eat both plants and animals Decomposers - eat dead matter (plants and animals)

Feeding Relationships Energy flows through an ecosystem in one direction from: 1. the sun or inorganic compounds 2. To autotrophs (producers) 3. To heterotrophs (consumers) Decomposers get energy from decomposing dead organisms

Food Chain- a series of steps in which organisms transfer energy by eating or being eaten. Food Web- A network of feeding relationships. (More realistic that a food chain)

Food Web

They can become very complex!

Trophic levels Each step in a food chain or a food web is called a trophic level. Producers are the first trophic level Consumers are the second, third, or higher trophic level Each trophic level depends on the one below for energy

Energy Pyramid Only 10% of the energy is transferred to next trophic level

Biomass Pyramid Biomass- the total amount of living tissue within a given trophic level. A biomass pyramid represents the amount of potential food available for each trophic level in an ecosystem.

Energy Losses Energy transfers are never 100 percent efficient Some energy is lost at each step Limits the number of trophic levels in an ecosystem Energy flow is a one way path! (not a cycle)

All Heat in the End At each trophic level, the bulk of the energy received from the previous level is used in metabolism This energy is released as heat energy and lost to the ecosystem Eventually, all energy is released as heat

Biogeochemical Cycles (Matter moving through the environment) All living organisms need certain elements/compounds for life processes Ex: your cells need C,H,O,P,N & S in order to live and reproduce (make more cell) Cycles in nature keep these elements “moving” from organisms to organism (and sometimes into the atmosphere)

Two Categories Hydrologic cycle Atmospheric cycles Water Nitrogen and carbon

CYCLES IN NATURE

Carbon Cycle Carbon moves through the atmosphere and food webs on its way to and from the ocean, sediments, and rocks Sediments and rocks are the main reservoir

Nitrogen Cycle Nitrogen is used in amino acids and nucleic acids (all living organism need nitrogen to make proteins) Main reservoir is nitrogen gas in the atmosphere Decomposers are vital to convert ammonia into: usable nitrites & nitrates for plants (nitrogen fixation) nitrogen gas (denitrification = puts it back into the atmosphere)