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Ecology. Unit 10. Words to know…. Ecology = The scientific study of interactions among organisms and between organisms and their environment Biosphere = Area of the earth where life exists; extends from the ocean’s depths to a few kilometers above land

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Unit 10

Words to know

Words to know…

  • Ecology = The scientific study of interactions among organisms and between organisms and their environment

  • Biosphere = Area of the earth where life exists; extends from the ocean’s depths to a few kilometers above land

  • Biome = Extensive areas of similar climate and vegetation; ecologists recognize at least ten different biomes

Words to know1

Words to know…

  • Biotic factors = living factors, such as plants and animals

  • Abiotic factors = non-living factors, such as climate, water, sun, rock, etc.

Terrestrial biomes

Terrestrial Biomes

Tropical rain forest

Tropical Rain Forest

  • Abiotic factors: hot and wet year-round; thin, nutrient poor soils

  • Dominant plants: broad-leaved evergreen trees; ferns; large woody vines and climbing plants

  • Geographic distribution: parts of South and Central America, Southeast Asia, parts of Africa, southern India, and northeastern Australia

Tropical dry forest

Tropical Dry Forest

  • Abiotic factors: generally warm year-round; alternating wet and dry seasons; rich soils subject to erosion

  • Dominant plants: tall, deciduous trees that form a dense canopy during the wet season

  • Geographic distribution: parts of Africa, South and Central America, Mexico, India, Australia, and tropical islands

Tropical savanna

Tropical Savanna

  • Abiotic factors: warm temperatures; seasonal rainfall; compact soil; frequent fires set by lightning

  • Dominant plants: tall, perennial grasses; sometimes drought-tolerant and fire-resistant trees or shrubs

  • Geographical distribution: large parts of eastern Africa, southern Brazil, northern Australia



  • Abiotic factors: low precipitation; variable temperatures; soils rich in minerals but poor in organic material

  • Dominant plants: cacti and other succulents; plants with short growth cycles

  • Geographic distribution: Africa, Asia, Middle East, United States, Mexico, South America, Australia

Temperate grassland

Temperate Grassland

  • Abiotic factors: warm to hot summers; cold winters; moderate, seasonal precipitation; fertile soils; occasional fires

  • Dominant plants: lush, perennial grasses and herbs; most are resistant to drought, fire, and cold

  • Geographic distribution: central Asia, North America, Australia, central Europe, and upland plateaus of South America

Temperate woodland and shrubland chaparral

Temperate Woodland and Shrubland (Chaparral)

  • Abiotic factors: hot, dry summers; cool, moist winters; thin, nutrient-poor soils; periodic fires

  • Dominant plants: woody evergreen shrubs with small, leathery leaves; fragrant, oily herbs that grow during winter and die in summer

  • Geographic distributions: western coasts of North and South America, areas around the Mediterranean Sea, South Africa, and Australia

Temperate forest

Temperate Forest

  • Abiotic factors: cold to moderate winters; warm summers; year-round precipitation; fertile soils

  • Dominant plants: broadleaf deciduous trees; some conifers; flowering shrubs; herbs; a ground layer of mosses and ferns

  • Geographic distribution: eastern United States; southeastern Canada; most of Europe; and parts of Japan, China, and Australia

Northwestern coniferous forest

Northwestern Coniferous Forest

  • Abiotic factors: mild temperatures; abundant precipitation during fall, winter, and spring; relatively cool, dry summer; rocky, acidic soils

  • Dominant plants: Douglas fir, Sitka spruce, western hemlock, redwood

  • Geographic distribution: Pacific coast of northwestern United States and Canada, from northern California to Alaska

Boreal forest taiga

Boreal Forest (Taiga)

  • Abiotic factors: long, cold winters; short, mild summers; moderate precipitation; high humidity; acidic, nutrient-poor soils

  • Dominant plants: needleleaf coniferous trees such as spruce and fir; some broadleaf deciduous trees; small, berry-bearing shrubs

  • Geographic distribution: North America, Asia, and northern Europe



  • Abiotic factors: strong winds; low precipitation; short and soggy summers; long, cold, and dark winters; poorly developed soils; permafrost

  • Dominant plants: ground-hugging plants such as mosses, lichens, sedges, and short grasses

  • Geographic distribution: northern North America, Asia, and Europe

Other land areas

Other land areas

  • Mountain Ranges – found on all continents, abiotic and biotic conditions vary with elevation

  • Polar Ice Caps – cold year-round, very few plants and algae

    • North polar region – dominant animals are polar bears, seals, insects, and mites

    • South polar region – dominant animals are penguins and marine mammals

Aquatic biomes

Aquatic Biomes

Aquatic ecosystems

Aquatic Ecosystems

  • Nearly ¾ of Earth’s surface is covered with water

  • Determined by depth, flow, temperature, and chemistry of the over-lying water

Flowing freshwater

Flowing freshwater

  • Rivers, streams, creeks, and brooks

  • Animals have adaptations, such as hooks, suckers, streamlined bodies, etc.

  • Often come from underground water source

  • Turbulent water = plenty of dissolved oxygen

Standing freshwater

Standing freshwater

  • Lakes and ponds

  • Water flows in and out, usually circulates  helps distribute heat and oxygen

  • Relatively still water allows organisms like plankton to survive

Freshwater wetlands

Freshwater wetlands

  • Wetland – ecosystem in which water either covers the soil or is present at or near the surface of the soil for at least part of the year

  • Bogs, marshes swamps

  • Support very specific plants and animals



  • Wetlands formed where river meets sea

  • Brackish = fresh water + salt water

  • Most organic material enters as detritus – made up of tiny pieces of organic material, consumed by clams, worms, sponges, etc.

  • Salt marshes = temperate zone estuaries

  • Mangrove swamps = tropical coastal regions

Marine ecosystems

Marine Ecosystems

  • Photic zone – relatively thin (200 meters) upper layer where light can penetrate  photosynthesis can occur

  • Aphotic zone – permanently dark, chemosynthetic producers only

  • Marine biologists divide ocean by photic and aphotic zones as well as depth and distance from shore

Intertidal zone

Intertidal Zone

  • Submerged in sea water once or twice a day, otherwise exposed to air and sunlight

  • Zonation – prominent horizontal banding of organisms that live in a particular habitat

Coastal ocean

Coastal Ocean

  • Extends from low-tide mark to outer edge of continental shelf

  • Shallow enough to mostly fall in photic zone  allows for plankton, kelp, etc. to survive

Coral reefs

Coral Reefs

  • Warm, shallow water of tropical coastal oceans

  • Named for coral animals whose hard, calcium carbonate skeletons make up their primary structure

  • Need warm water, bright sun, and salt, grow with help of algae

Open ocean

Open ocean

  • Begins at edge of continental shelf and extends outward

  • 90% of the surface area of the world’s ocean

  • Organisms are exposed to high pressure, frigid temperatures, and total darkness

  • Most productivity occurs in photic zone

Benthic zone

Benthic zone

  • Ocean floor

  • Creatures that live here (such as sea stars, anemones, marine worms, etc.) are called benthos

  • Often depend on food from organisms that grow in the photic zone that drifts down

Ecosystems populations and communities

Ecosystems, Populations, and Communities



  • An ecosystem is a physically distinct, self supporting unit of interacting organisms and their environment

  • Includes biotic and abiotic factors

  • Four important processes:

    • Production of energy (usually from sunlight)

    • Energy transfer

    • Decomposition

    • Reuse of nutrients

Communities and populations

Communities and Populations

  • Community = all of the ecosystem’s interacting biotic factors

  • May be broken down into smaller units called populations

  • Population = a group of individuals that belong to the same species, occupy the same area, and share common resources

  • Each population has a specific niche, which means total way of life  habitat, place in food web, competition, interrelationships, and resource needs

  • A community may have 1000’s of populations (rain forest) or relatively few (tundra)

How does energy move through an ecosystem

How does energy move through an ecosystem?

  • Organisms in a community survive by either producing or consuming food

  • Trophic level = level of feeding in a community

  • Producers produce food for themselves

  • Consumers must take in food from other sources

How does energy move through an ecosystem1

How does energy move through an ecosystem?

  • Primary consumers eat producers  “herbivores” (eat only plants)

  • Secondary and Tertiary consumers can be carnivores (eat only meat) or omnivores (eat plants and meat)

  • Decomposers break down wastes and dead organisms, return nutrients to soil

Food webs

Food webs

  • Made up of overlapping food chains

  • Shows feeding connections

  • Arrows illustrate energy transfer  flow in direction of energy

Energy efficiency

Energy efficiency

  • Producers have most available energy (from sun)

  • Energy is lost as it moves up through the food web  “10% rule” = only 10% of the energy is transferred to the next highest trophic level

  • The “lost” energy is used to catch, eat, and digest food.

  • Decomposers return nutrients and energy to soil.

How do populations change over time

How do populations change over time?

  • Population growth – populations will grow until they reach their carrying capacity  exponential growth – “J curve”

  • Limiting factors, such as availability of food, space, mates, etc. establish the carrying capacity (the # of individuals an environment can support) – “S curve”

Ecological succession

Ecological Succession

  • Succession = the idea that communities will replace other communities in a predictable, orderly way because every community alters the physical factors of the environment

  • Two kinds:

    • Primary – occurs in areas that have not supported communities before

    • Secondary – occurs in areas that have supported communities before

Ecological succession1

Ecological Succession

  • Pioneer species – first organisms to inhabit an area, must be able to survive harsh conditions

  • Intermediate communities – multiple communities that each change the environment and “pave the way” for other communities

  • Climax community – final stage in succession, most stable community for that biome

Community interactions

Community interactions

How do living things interact in a community

How do living things interact in a community?

  • Competition = a struggle for resources among organisms

  • Predation = organisms consume other organisms

    • Predators = organisms doing the eating

    • Prey = organisms getting eaten

  • Symbiosis = two organisms of different species living together in a close, permanent relationship



  • Mutualism – the two organisms benefit each other

  • Commensalism – one organism benefits and the other is neither benefitted nor harmed

  • Parasitism – one organism benefits and the other is harmed

Biogeochemical cycles

Biogeochemical Cycles

Biogeochemical cycles1

Biogeochemical Cycles

  • Pathways through which a substance is recycled.

  • Water cycle

  • Carbon cycle

  • Nitrogen cycle

Water cycle

Water Cycle

  • Enters ecosystem through precipitation, could be absorbed into soil or run-off into surface water

  • Returns to atmosphere through evaporation or transpiration (loss of water by plants)

Carbon cycle

Carbon Cycle

  • Powered by two main processes:

    • Photosynthesis – plants and algae capture CO2 from air and change it to sugar which contains carbon

    • Respiration – all living things break down sugars for energy, which returns CO2 to atmosphere

  • Other factors:

    • Decomposition returns carbon to soil and atmosphere

    • Humans burn fossil fuels which adds CO2 to atmosphere

Nitrogen cycle

Nitrogen Cycle

  • Nitrogen is essential for living organisms so that they can build proteins

  • Nitrogen is plentiful in the atmosphere, but not usable in this form

  • Nitrogen fixation = bacteria living in the root nodules of bean plants convert nitrogen from the air into a more usable form

  • Nitrogen fixation is the first of many steps that involves bacteria and changing the form of nitrogen

Studying ecology

Studying Ecology

What technology helps scientists study the complex systems in ecology

What technology helps scientists study the complex systems in ecology?

  • Global positioning system – satellite based navigation system that allows the exact determination of a location. This is used for GIS (geographic information systems) which can:

    • Store, manage and integrate data relating to points (individual trees), lines (rivers, roads), and boundaries

    • Search for areas with a particular factor (ex. species)

    • Perform geographical analysis

    • Display data in maps

What technology helps scientists study the complex systems in ecology1

What technology helps scientists study the complex systems in ecology?

  • Biological Sampling – techniques that allow scientists to quantitatively evaluate an area in terms of its biotic factors

    • Mark/recapture method – allows scientists to estimate a population number in area, scientist captures a segment of population, marks them, releases them, and then recaptures another segment of the population, counting the number of “marked” individuals recaptured, using these numbers to estimate the total population size.

What technology helps scientists study the complex systems in ecology2

What technology helps scientists study the complex systems in ecology?

  • Quadrant analysis – scientists use a quadrant to select an area of an ecosystem  reduces space a scientist must analyze, ensures the size of area remains the same if the scientist chooses to analyze several areas or the same area over a period of time

  • Water/soil analysis – using chemical tests or sampling techniques to determine the chemical or physical characteristics of water or soil

Human impact

Human Impact

Human population

Human Population

  • Human population has been growing exponentially since the industrial age better medicine, better living conditions, more food = more people

  • Current Population

Human population graph

Human Population - Graph

  • Separated down the middle: right side = female, left side = male

  • Organized vertically by age

  • Organized horizontally by percent of total population

Developed vs developing countries

Developed vs. Developing Countries

  • Developed

    • 20% of population

    • 85% of wealth

    • Average life span – 78 years

    • Infant deaths per 1000 births – 9

    • Population under 15 – 19%

  • Developing

    • 80% of population

    • 15% of wealth

    • Average life span – 63 years

    • Infant deaths per 1000 births – 64

    • Population under 15 – 35%

Human activity

Human Activity

  • Pollution = process that releases harmful substances into the air, land, or water

  • Acid rain = rain that contains nitric and sulfuric acids

Human activity1

Human Activity

  • Pesticides = Chemicals used to kill insects by farmers; some insects survive and develop a resistance

  • Deforestation = Cutting down plants for fuel, agriculture, etc. This results in less photosynthesis and more CO2 in the atmosphere

Human activity2

Human Activity

  • Greenhouse gases = Trap UV radiation from the sun, raises the temperature of the Earth (CO2)

  • Ozone depletion = Ozone layer reflects UV radiation back to the sun; less ozone = more gets through to heat the Earth

Human activity3

Human Activity

  • CFCs= Chlorofluorocarbon; an organic compound usually found in refridgerants, aerosols, and solvents, destroys ozone layer

  • Fossil fuels = Hydrocarbons (hydrogen and carbon) formed from organisms that died millions of years ago, release CO2 when burned; ex. coal and oil

Human activity4

Human Activity

  • Keystone species = used as a standard to evaluate the health of an ecosystem; more sensitive to biological changes than other species

  • Native species = those that originate or occur naturally in an area or environment

  • Invasive species = those that are artificially introduced to an area or environment; can be very destructive

Human activity5

Human Activity

  • Bioaccumulation = accumulation of a substance, such as a toxic chemical in the tissues of a living organism

  • Biomagnification = the increasing concentration of these toxins at successively higher trophic levels in a food chain

Animal behavior

Animal Behavior

What is behavior

What is behavior?

  • The way an organism reacts to changes in its internal condition or external environment.

  • Stimulus = any kind of signal that carries information and can be detected

  • Response = a single, specific reaction to a stimulus

Different types of behavior

Different types of behavior

  • Innate behavior = instinct, inborn behavior; fully functional the first time they are performed, even if the animal may have had no previous experience with the stimuli to which it responds

  • Learned behavior – learned, developed responses, more common in animals with more complex nervous systems, four major types are habituation, classical conditioning, operant conditioning, and insight learning


  • Habituation – process by which an animal decreases or stops its response to a repetitive stimulus that neither rewards nor harms the animal

  • Example: A puppy is frightened by the vacuum cleaner, so he barks and growls at it. After a while, he realizes it is not hurting him, so he stops barking and growling.



  • Classical conditioning – animal makes a mental connection between a stimulus and some kind of reward or punishment.

  • Example: Ivan Pavlov noticed that dogs salivate when they are about to eat. He rang a bell every time he fed his dog, and eventually, just ringing the bell would cause the dog to start drooling. The dog had associated the bell with being fed.



  • Operant conditioning – when an animal learns to behave a certain way through repeated practice (trial and error) in order to receive a reward or avoid a punishment  motivation

  • Example: B. F. Skinner invented the “Skinner box,” which contains a colored button that releases food if the animal inside presses it. Eventually, the animal will learn to press the button whenever it wants food.



  • Insight learning – the animal applies something it has already learned to a new situation without “trial and error”  reasoning

  • Example: A chimpanzee piles boxes on top of each other in order to reach bananas that are out of his reach.


Combining innate and learned behavior

Combining innate and learned behavior

  • Imprinting – young animals recognize and follow the first moving object they see. They have an innate urge to follow the first thing they see, but they do not know what it will look like.


Behavioral cycles

Behavioral cycles

  • Migration – periodic movement from one place to another and then back again, usually influenced by changing seasons

  • Circadian rhythms – daily patterns of behavior, such as sleeping at night and being active during the day

  • Estivation – animals reduce their metabolism during the summer or periods of extreme heat

  • Hibernation- animals reduce their metabolism during the winter or periods of extreme cold



  • An animal must locate and mate with another member of its species in order to pass on its genes.

  • Courtship rituals – series of behaviors performed the same way by all members of a population, continues until mating occurs.


Social behavior

Social Behavior

  • Membership in a society can provide protection from predators

  • Members of a society are closely related to one another  helping a relative survive increases the chance that the genes an individual shares with that relative will be passed along to offspring

Defensive behavior

Defensive Behavior

  • Mimicry – an animal imitates a more dangerous animal to discourage predators

  • Crypsis– an animal can blend into the background or stand very still in the presence of a predator to avoid detection

  • Vigilance – an animal actively looks, listens, sniffs, etc. for predators




  • Territory – specific area occupied and protected by an animal or group of animals, usually contains resources like food, water, mates, etc.

  • Aggression – threatening behavior that one animal uses to gain control over another



  • The passing of information from one individual to another

  • Visual signals – using movement, color, shape, etc. to communicate

  • Chemical signals – using scents, pheromones, etc. to communicate

  • Sound signals – using specific sounds to communicate

  • Language – combination of sounds, symbols, and gestures according to sets of rules about word order and meaning, only used by humans or animals trained by humans



  • Thermotaxis– attraction to heat, move towards it

  • Chemotaxis– attraction to chemical, usually detected through taste or smell, move towards it

  • Phototaxis– attraction to light, move towards it

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