Ecology Unit 40% of the EOC

What is Ecology?

• Ecology is the scientific study of interactions among organisms and between the organisms and their environments.

• An ecosystem is the sum of all the living and nonliving things in an area and the interactions among them.

Levels of Organization• Page 64 - 65 in Textbook Copy all the

levels of organization Figure 3-1 and give a specific example for each level

Levels of Organization• Biosphere

– All areas of the earth from the ocean depths to the atmosphere that support life.

Ecological roles

• Autotrophs - Producer • Capture energy and store it in the chemicals bonds of

glucose and other simple food molecules • Heterotrophs - Consumer

• must eat other organisms for food; • primary (mouse), secondary (fox), tertiary (bobcat)

**From page 71 in textbook Copy Figure 3-6 with an example of each type of animal.

HW 3.2 assessment pg 72 1-3

Food Chain

The path of food and energy from producer to consumer to decomposer

Food Web

Food chains that interconnect through multiple feeding relationships

• Each feeding level in an ecosystem is a trophic level

• Energy pyramids show the energy loss between trophic levels in an ecosystem

• Only about 10% of energy from each trophic level is passed to the next level

• All of the living matter in a habitat, trophic level or ecosystem is its biomass

Trophic Levels

Video – Pole to Pole

• Answer the handout on the video – do not forget about the trophic pyramid and food web on back of paper

How do nutrients cycle?

• Energy follows a ONE-WAY path– Sun living organisms heat atmosphere– The planet does not create or receive more of elements

when needed instead they cycle between the biotic (living) and abiotic(nonliving) parts of the biosphere

• Matter CYCLES through living organisms endlessly• Biogeochemical cycles

– Carbon and Oxygen– Water– Nitrogen

Carbon and Oxygen Cycle

Carbon/Oxygen Cycle

The continual transfer of carbon and oxygen Between living and nonliving parts of the environment

Involves processes such as photosynthesis, cellular Respiration, decomposition and combustion (burningof fossil fuels)

Nitrogen Cycle

Nitrogen cycle – not on EOC

• Continual movement of nitrogen among earths organisms, water, rocks, minerals and atmosphere.

• Nitrogen fixation is a process in which certain soil bacteria break down N2 and nitrogen found in dead organic matter and convert it to either nitrate or ammonia. These forms of nitrogen are easily absorbed by plant roots.

• Denitrification – Bacteria convert nitrogen compounds back to nitrogen compounds back to nitrogen gas.

Water Cycle

Water CycleAlso called the hydrologic cycle is the continuouscirculation of water among Earths organisms, atmosphereand surface Evaporation – change of liquid to gas when heatedTranspiration – release of water through stomata (openingsIn a plants leaves.Condensation – gas changes to liquid when it loses thermalenergyPrecipitation – water that falls from atmosphere to Earth asRain, snow, sleet or hail

In your notebooks

Using the Pictures given to you label the water cycle and carbon cycle on separate papers with all processes labeled and arrows showing the direction of water, CO2 and O2

The role of Climate

• Weather- the day to day condition of earths Atmosphere at a particular time and place

• Climate – average, year after year conditions of temperature and precipitation in a particular region

Aquatic Ecosystems• Many of the Earths organisms live in or

near water. Aquatic ecosystems are defined by salinity, chemistry, geography, depth, flow, light conditions and water temperatures.

• Salinity is a measure of the amount of salt in fresh water.

• Key factors that affect concentration of animals are dissolved oxygen and water temp. Cold water holds more Oxygen

Aquatic Ecosystems

• Estuaries – form where salty ocean water mixes with freshwater from rivers

• Wetlands – water covers soil or is present near the surface of the soil for at least part of the year. Ex: bogs, swamps and marshes.

Marine Ecosystems

• Defined by water with high salinity• Divided into zones• Intertidal zone – part of shore between

high tide mark and low tide mark. Affected twice daily by tides

• Neritic zone- slopes down from shoreline toward ocean floor

• Oceanic zone – extends from surface to ocean floor

• Upwellings – movement of cool nutrient rich waters from deep ocean into shallower ocean areas.

• Hydrothermal Vents – crack in ocean floor that emits hot mineral rich water that are heated by magma

• Chemosynthesis – process by which bacteria use chemicals for energy

Ocean Life

• Benthos – live on or near ocean bottom• Plankton – organisms carried by ocean

currents• Nekton – free swimming organisms

Ecosystem Changes and Succession

• Seasonal changes affect ecosystems some animals migrate in response to changes

• Migration – instinctive seasonal movement of animals from one place to another – usually for food, water or mating

Ecological Disturbances • Disturbance – event that leads to changes in the

composition of an ecosystem• Succession – the natural process following a

disturbance in which one community of organisms gradually replaces another

• Primary Succession – gradual development of a new community from nothing

• Secondary succession – when a disturbance changes or partially destroys an ecosystem without destroying its soil. (abandoning farmland or leaving logged forest to regrow)

• Pioneer species – first species to move into a devestated area

• Climax community- fairly stable community that marks the end of succession

Primary Succession

Population Dynamics

• All species have requirements for many factors/conditions. – Abiotic factors – non-living factors; ex.

temperature, precipitation, pH– Biotic factors – other species; ex. prey

species, competing species– Immigration – movement of organisms

into an area– Emmigration – movement out of an area

Limiting Factors

• Anything in an environment that can limit the size of a population is called a limiting factor

Abiotic Factors Biotic FactorsSunlight Pathogens

Soil (type, ph) Predators and Prey

Water Competiton

Natural disasters (earthquakes, floods, hurricanes etc)

Symbiosis

Population Density

• Density dependent limiting factor – depends on the size of the population –

• Population density – measure of the number of organisms in a given area

• Density Independent Factors – Limit the size of the population regardless of size

• Carrying Capacity – The largest population that an environment can hold for a long period of time

What would the carrying capacity of this fly

population be?

– The lesson of the KaibabAssignment

Biodiversity

• Biodiversity – refers to the number of different kinds of organisms living on Earth or an ecosystem.

• Extinction – dying out of species• Mass extinction – dying off of large numbers of

species in a short period of time• Habitat place where an organism usually lives• Habitat destruction – habitat is destroyed or changed

so that it can no longer support the species that had lived there

• Invasive Species – an introduced species that harms the environment into which it is introduced. Ex: zebra mussels, pythons in everglades, lionfish

Humans Affect the Environment

• Renewable resources – Resources that can be replaced at rates similar to the rates in which they are used ex: forests, freshwater

• Nonrenewable resources – used much faster than can be replaced ex: fossil fuels(oil, coal, natural gas)

• Air Pollution – release of harmful substances substances or energy into the air

• Particulates – small airborne particles of dust, soot and other solids

• Smog – visible haze that forms when smoke and gases from burning fuels combines with fog

• Deforestation – removal of all tress in a forest • Ozone layer – Ozone layer in atmosphere

made up of 3 Oxygen atoms – absorbs much of suns harmful rays

• Water pollution – release of harmful substances into bodies of water

Sunlight

Some heatescapesinto space

Greenhousegases trapsome heat

Atmosphere

Earth’s surface

Greenhouse Effect

The greenhouse effect• Carbon Dioxide, methane, water vapor

and a few other atmospheric gases trap heat energy of sunlight

inside the earths atmosphere (just like glass keeps a greenhouse warm)

Effects on Biodiversity

• Overfishing• Desertification – transformation of

productive land into a desert

Conservation and Sustainable Practices

• Reduce • Reuse • Recycle• Sustainable development – involves

using resources in ways that do not destroy or deplete them for future generations