Ecology -

Deals with interactions among organisms Interactions between organisms and the environment

Dependent on Biotic factors -Effect of living organisms in the environment, both direct and indirect Abiotic factors – effect of non living – water,oxygen, light, temperature, soil, organic and inorganic nutrients

Light

Energy for all living things comes directly or indirectly from the sun Aquatic environments – light is absorbed as it passes through water

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Photic layer of water which has light Aphotic layer – no light

Water+oxygen ,in the presence of sunlight = producers make glucose

Temperature Vary with latitude and altitude (vertical distance above sea level) Nearby geographic features

Soil and minerals

Soil –mostly smaller rock particles broken down from larger by water and wind weathering Minerals in the soil dependent on the kind of rock from which it has been weathered

Soil

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Topsoil Uppermost layer organic matter(humus) and living organisms, plant roots, earthworms,insects Humus – from decay of dead plants and animals Organisms of decay – fungi and bacteria

Next layer – subsoil Rock particles mixed with inorganic compounds Including minerals

Bottom layer Bits of rock broken off from the bedrock below

Types of soil Sandy

– largest particles water drains too quickly

Clay

– small particles – water drains too slowly

Silt

– intermediate size

Biosphere – portion of the earth where living things exist divided into 1.

Lithosphere earths surface 2.

Hydrosphere – solid part of –water 3.

Atmosphere – mass of air surrounding the earth

Population area - all individuals of a particular species in a certain Community – all the populations of different organisms in a particular area Ecosystem – community + it’s physical environment

Ecosystems contain….

Autotrophs – make their own food using carbon dioxide,water and the suns energy – plants Herbivores Producers Heterotrophs : consumers (plant eating); carnivores (meat eating); Omnivores (both plant and animal eaters) Predators (attack and kill prey) ; scavengers – (feed on dead animals) ; Saprobes (break down remains of dead organisms) decomposers – bacteria,fungus

Symbiotic relationships Two different organisms live in close association Mutualism – both organisms benefit

Commensalism –one organism benefits and the other is not affected

Parasitism One organism benefits and the other is harmed

Habitat each organism has a particular place where it lives Niche – particular role in an ecosystem

Food chains and food webs – feeding relationships Energy stored in organic nutrients transferred to consumers Herbivores – first order consumers Carnivores – second order consumers

Food webs

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Pyramid of energy and biomass Amount of energy available at each level decreases with each higher feeding level Usually level 10% of energy (biomass) transferred at each

Energy transfer

Only 10% transferred at each level

Biogeochemical cycles

Materials recycle between living things and the environment Nitrogen,carbon,oxygen,water

Nitrogen cycle

Basic component of proteins and nucleic acids Even though nitrogen is about 80% of the atmosphere plants cannot use it directly Nitrogen fixation – specialized bacteria in legumes convert nitrogen to nitrates which plants can use

Nitrogen cycle

Carbon and Oxygen cycle Carbon Oxygen - .03% of atmosphere, dissolved waters of the ocean, converted by plants into organic compounds during photosynthesis – 20% of atmosphere – released into atmosphere during photosynthesis and removed by cellular respiration

Carbon – Oxygen cycle

Water cycle Cycling of water between the surface of the earth and the atmosphere

Ecological succession

Process by which an existing community is slowly replaced by another one.The species that has the greatest effect on the community is called the Dominant species.

Succession continues until a climax community is reached.

Primary succession – is in an area that has no existing life – rocky cliffs, newly formed volcanic islands

Secondary succession been abandoned – area in which an existing community has been destroyed – farmed land which has

Succession in lakes and ponds Sediment,fallen leaves accumulate in the bottom > moss and reeds grow on the banks >lake gets filled in and become marsh > dry land

Human ecology

- Chapter 39 relationship between humans and the environment

Human population growth

year 2000 - 6 billion Limiting factor - limits further growth - lack of food Carrying capacity - size of a population that can be supported by an environment

Population remains the same if the birth and the death rates are equal and there is no change from migration Developed - death rate low - good medical care Developing - birth rate high - population growth

Urbanization

population moves to cities destruction of farmlands to make housing over farming and overgrazing fields without vegetation - soil removed by wind and water causing erosion

Pollution

adding anything to the environment that makes it less fit for living things noise pollution pesticides - contaminates air,water,disrupts food chains - DDT

continued……

air pollution - sulfur dioxide(burning of coal) mixes with rain water to produce ACID RAIN ; carbon monoxide and nitrogen oxides( car exhaust ,industry) water pollution - eutrophication explosive growth of algae,uses up all the dissolved oxygen and the fish die Land pollution - sanitary landfill, burning refuse in incinerators

Restoring the environment

controlling pollution - car emissions and unleaded gasoline sewage treatment breakdown sewage before it goes back to waterway recycling and reusing to avoid filling land fills

Conserving Natural Resources

Renewable -air,water,soil,sunlight, nonrenewable - coal,oil,natural gas,metals,minerals biological pest control pheromones conserving wildlife- legal protection of endangered species conserving forests - reforestation

Conserving soil

Strip cropping - cover crops planted between strips of regular crops Terracing - sides of hills Contour farming - rows on slopes windbreaks - prevent wind erosion