Ecology SC Standard B-6: The student will demonstrate an understanding of the interrelationships among organisms and the biotic and abiotic components of their environments.

Ecosystem- a community of all the organisms in a given area and the abiotic factors that affect them. A stable ecosystem is where: The population numbers of each organism fluctuate at a predictable rate The supply of resources in the physical environment fluctuates at a predictable rate Energy flows through the ecosystem at a fairly consistent rate over time Interrelationships:

Predation- the interaction between species in which one species(the predator) eats the other (prey) As the prey population ^ the predator population ^ and the reverse is true. Competition- a relationship that occurs when 2 or more organisms need the same resource at the same time Interactions

Symbiotic Relationships: A symbiotic relationship exists between 2 different species that live together in direct contact. The balance of an ecosystem is adapted to this relationship. If it becomes unbalanced- the populations of both species will fluctuate Examples- parasitism, mutualism, and commensalism Symbiotic Relationships:

One organism benefits (parasite) at the expense of the other organism- the host. Some parasites live in the host- tapeworms, heartworms or bacteria Some feed on the external surface of the host- such as fleas, aphids and mistletoe Often results in death- but it is important that the host survive long enough to reproduce and spread. Parasitism

Mutualism A symbiotic relationship in which both organisms benefit. Because they work closely together- they help each other survive. Examples- bacteria that digest wood live in the digestive tracks of termites Plant roots provide food for fungi that break down nutrients plant need.

A symbiotic relationship in which one benefits and the other is not affected. Examples- barnacles that attach to whales are dispersed to different environments where they can obtain food and reproduce Cattle and egrets- cattle stir up insects for the birds- cattle unaffected by presences Commensalism:

mutualism

Parasitism

commensalism

Measure of the number of individuals living in a defined space Measure of the number of individuals living in a defined space. Affected by limiting factors Density- dependent factors- affects larger populations- includes predation, competition, parasitism and disease- triggered by increases in populations- overcrowding Population Density

Density independent- occur regardless of how large the population is and reduce the size of all the populations in the area. Mostly abiotic- weather changes- human activities- pollution- and natural disasters- fires/ hurricanes More:

Limiting Factors: Limiting factors can change within an ecosystem and affect populations Abiotic factors- may be chemical or physical such as- water, salinity, pH, nutrients, temperature, amount of sunlight and precipitation Biotic factors- all the living components- such as fungi, bacteria, plants and animals. A change in either may increase or decrease a population if they can not acclimate, adapt or migrate from the change

Ecological Succession: A series of changes in an ecosystem where one community is replaced by another community as a result of changes in abiotic and biotic factors Two types- primary and secondary Ecological Succession:

Areas not previously inhabited Areas not previously inhabited. Examples- bare rock surfaces from lava flow or receding glaciers - Lichens and mosses are first to arrive = pioneer species Small plants- flowers, ferns and shrubs- grow Eventually – a mature community (climax community)- results. Little to no change taking place. Primary Succession:

Secondary Succession: Begins in areas where there was a preexisting community and well formed soil. Examples- abandoned farmland, vacant lots, clear cut forests, or open area produced by forest fires. Similar to Primary Succession except soil is already formed Succession is a continual process Secondary Succession:

Movement of a particular form of matter through the living and non living parts of an ecosystem. Matter changes form but is neither created or destroyed. - used over and over again in a continuous cycle Geochemical Cycles:

Carbon Cycle: Carbon is a major component of all living organisms Found in atmosphere, minerals and rocks, fossil fuels (natural gas, coal and petroleum) and materials that compose soil and aquatic sediments Photosynthesis, respiration, decomposition, combustion and weathering are all parts of the Carbon Cycle Carbon Cycle:

Nitrogen is a critical component of Amino Acids- which is needed to build proteins Nitrogen is found in the atmosphere and organic materials that compose soil and aquatic sediments Organisms play a major role in recycling nitrogen- nitrogen fixation, decomposition, denitrification, & intake through roots Nitrogen Cycle:

Water/Hydrologic Cycle: Water is a necessary substance for life processes in all living organisms Found in atmosphere, on surface of Earth, underground & in organisms Water cycle is driven by the Sun’s heat energy- evaporation Organisms recycle water- intake, transpiration, respiration, & elimination Water/Hydrologic Cycle:

Naturally occurring Earth processes Help ecosystems maintain the materials necessary for organisms in that ecosystem Maintaining the quality of the atmosphere is the result of life processes Plants, animals cycle oxygen/CO2 naturally. Other cycles help Greenhouse effect- normal warming effect when gases trap heat in atmosphere

More Greenhouse Effect: Greenhouse gases such as CO2, O2, methane and water vapor trap heat energy to maintain Earth’s temp range GHG do not allow heat to pass through very well, so it stays trapped. When the amount of CO2 in the atmosphere is higher, the greenhouse effect ^, the global temp^, Plant cover^, rate of photosynthesis^, CO2 absorbed by plants ^, CO2 in atmosphere goes down Opposite is true. More Greenhouse Effect:

Still more: Generating Soils- soil on Earth is constantly being generated and eroded Composed of 4 distinct components: inorganic minerals, organic matter, water and air. Soil erosion and deposition are natural processes that move soil. Presence of plants helps soil stay constant Presence of soil in ecosystem allows for succession to take place

Just a bit more, Hydrologic Cycle is maintained by energy of the Sun and effect of weather Water is purified in many ways: evaporated water, seeping through soil, & water flow slows- allowing heavier particles to settle out -Waste materials are decomposed by bacteria -nutrients are cycled through ecosystem -there are cycles for every nutrient present in living organisms