Ecology

The first law of ecology is that everything is related to everything else.

~Barry Commoner

Warm-Up

• Do this on your OUTPUT side!

• Think of your favorite outdoor spot.

• List all of the living things that exist there.

• List all of the non-living aspects of your experience there.

The Biosphere

Chapter 34

Concept 34.1

• The biosphere is the global ecosystem.

• Key Terms• Ecology• Biotic factor• Abiotic factor• Population• Community• Ecosystem• Biosphere• Habitat

The Study of Ecology

• Ecology• Study of

interactions among organisms and their environments

• Biotic vs. Abiotic

Ecological Relationships

• Classified by broad levels:• Organisms• Populations• Communities• Ecosytems• Biosphere

Individual Organisms

• Smallest unit of ecological study

• Ecologists ask questions about the adaptations that enable individuals to meet the challenge of their environment

Populations

• Group of the individual organisms of the same species living in a particular area

• Ecologists often ask questions about factors that affect the size and growth of a population

Communities

• All of the organisms inhabiting a particular area

• Ecologists investigate interactions among all of the organisms in a community

Ecosystems

• Includes the biotic and abiotic factors in an area

• Questions at the ecosystem level may relate to the flow of energy and chemicals

Biosphere• Broadest of all levels of

ecological study

• Sum of all of the Earth’s ecosystems

• Questions at the biosphere level involve global issues, such as investigating the effects of climate change on living things

Patchiness of the Biosphere

• Differences in the abiotic factors of a location leads to a “patchy” appearance like a quilt

• Each of these “patches” are different habitats for organisms to live in

Chlorophyll Concentrations

Key Abiotic Factors• Sunlight

• Provides light and warmth and is an energy source for all ecosystems

• Water• Essential to all life on

Earth – all organisms contain water

• Temperature• Life exists at a very

narrow range of temperatures (0-50°C)

• Soil• Product of abiotic

forces and the actions of living things

• Wind • Can affect the

distribution and activities of organisms

• Severe Disturbances• Naturally affect the

ecosystems – fire, hurricanes, droughts,

Concept 34.2

• Climate determines global patterns in the biosphere.

• Key Terms• Tropics• Polar zones• Temperate zones• Current• Microclimate

Uneven Heating of the Earth’s Surface

• The angle that the sun’s rays hit the Earth causes different temperature gradients

• Tropics• Polar Zones• Temperate Zones

Wind, Precipitation & Ocean Currents

• Global wind patterns and Earth’s rotation create warm and cold surface currents in the oceans

• These surface currents affect the climate on the continents

Local Climate

• Local climate can be affected by:• Bodies of

Water• Mountains

Microclimate

• Climate in a specific area that varies from the surrounding climate region

• Microclimates can be created by:• Shade• Snow cover• Windbreaks

Concept 34.3• Biomes are the major types of terrestrial ecosystems.

• Key Terms• Biome• Tropical rain forest• Savanna• Desert• Chapparral• Temperate grassland• Temperate deciduous forest• Coniferous forest• Tundra• Permafrost

What is a Biome?

• Major types of terrestrial ecosystems that cover large areas of Earth

• Biomes are characterized by communities of plants and other organisms that are adapted to its climate and other abiotic factors

Tropical Rainforest

• Characterized by tall trees• Treetops = Canopy

• Contain epiphytes• Don’t get enough

sunlight at the floor of the rainforest

• Often live on the branches of tall trees

• Not parasitic because they make their own food

Tropical Rainforest• Highest species

richness• 1 Hectare = 300

species• Temperate forest

• 1 Hectare = 10 species

• Animals:• Sloth, colorful birds,

monkeys, snakes, and lizards

• Maybe be 8 million species of beetles in the rain forest

Savanna

• Tropical or subtropical grasslands with scattered trees and shrubs

• Alternating wet and dry seasons• More rain than deserts• Less rain than

rainforests

Savanna

• Animals:• Zebras, giraffes,

and gazelles• Lions, leopards,

and cheetahs

Desert

• Receive less than 25 cm of rainfall per year

• Deserts are NOT hot all the time

• Desert vegetation is often sparse and consists of plants that have adapted to the dry climate

Desert• Plant adaptations:

• Waxy coating• Protective spines

• Plants and animals have adaptations to conserve what little water they receive

• Animals:• Kit foxes, snakes,

and lizards

Chaparral

• Dominated by dense evergreen shrubs

• Dry climate consists of mild, rainy winters and hot, dry summers

Chaparral

• Chaparral’s dry, woody shrubs often ignite by lightning and are adapted to survive periodic brushfires

Temperate Grassland

• Form in the interior of continents, at about the same latitude of temperate deciduous forests

• Known by different names in different places:• Prairie = N.

America• Steppes = Asia• Pampas = S.

America• Veldt = Africa

Temperate Grassland

• Because of its rich soil – grasslands have been transformed into farmland for crops such as wheat and corn

• Very little undisturbed portions of the grasslands in the world

Temperate Deciduous Forest

• Characterized by trees who lose their leaves in the fall

• These regions have pronounced seasons, with precipitation throughout the year

Temperate Deciduous Forest

• Animals:• Deer, foxes, squirrels,

and raccoons

• Large areas of temperate deciduous forests have been cut down for timber or cleared to make room for farms, towns, and cities

Coniferous Forest / Taiga

• South of the tundra

• Dominated by cone-bearing trees (pines, firs, hemlocks, and spruce)

• Plants in the taiga are adapted to long and cold winters, short summers, and nutrient-poor soils

Coniferous Forest / Taiga

• Typical animals:• Moose• Bears• Wolves• Lynx

• Some animals stay in the forest year-long

• Many species hibernate 6-8 months of the year

Tundra

• Cold and largely treeless, surface covered with permafrost (permanently frozen soil)

• Receives little precipitation

Tundra

• Tundra plants are usually small and grow slowly• Grasses, sedges,

and mosses

• Animals • Caribou, musk

oxen, snowy owls, artic foxes, lemmings, and snowshoe hairs

Concept 34.4• Aquatic ecosystems make up most of the biosphere.

• Key Terms• Photic zone• Phytoplankton• Aphotic zone• Benthic zone• Estuary• Pelagic zone• Intertidal zone• Neritic zone• Oceanic zone• Zooplankton• Hydrothermal vent

Aquatic Ecosystems

• Water covers ¾ of the Earth and is home to a variety of organisms• Freshwater zones

• Lakes and ponds• Rivers and streams• Estuaries

• Ocean zones• Intertidal zone• Neritic zone• Oceanic zone

Freshwater Zones

• Low levels of salt (0.0005% salinity)

• Freshwater ecosystems include:• Lakes• Ponds• Streams• Rivers

Lakes and Ponds

• Freshwater Lakes and Ponds support:• Otters, Muskrats, Birds (Ducks and Loons),

and Fish

• Eutrophic• Rich in organic matter and vegetation• Water is relatively murky

• Oligotrophic• Very little organic matter• Water is much clearer, bottom is usually

sandy or rocky

Lakes and Ponds

Rivers and Streams

• Body of water that flows down a gradient towards its mouth

• Water flows swiftly down steep gradients, organisms are adapted to withstand powerful currents

• Brook trout face upstream to catch passing drifting invertebrates

• Slow-moving rivers and backwaters are richer in nutrients and support more life

• Rooted plants and fishes are adapted to weaker currents in slow-moving rivers

Rivers and Streams

Estuaries

• Place where freshwater meets sea water

• Examples:• Bays• Mud flats• Salt marshes

• Inhabitants are adapted for frequent changes• Mangrove trees have salt glands that secrete

salt from salt water

Estuaries

Ocean Zones• The ocean covers 70% of the Earth’s

surface, with an average depth of 3.7 km • At the deepest parts the depth is 11km deep

• Different Oceanic Zones• Aphotic – cold and dark, no sunlight• Photic – receives sunlight• Intertidal – along the oceanic shore, tides rise

and fall• Neritic – relatively shallow, just beyond the

intertidal zone• Pelagic – open ocean• Benthic – ocean bottom

Ocean Zones

Oceanic Zones

Intertidal Zone

• Organisms in this zone are adapted to periodic exposure to air during low tide• Crabs avoid dehydration by burrowing into

the sand or mud

• Organisms in this zone must be able to withstand the force of crashing waves• Sea anemones cling to rocks • Sea stars use tube feet to adhere to surface

Intertidal Zone

Neritic Zone

• Most productive zone of the ocean

• Waters are rich in plankton

• Coral reefs are productive and rich in species

• Animals:• Many species of fish• Crustaceans• Mollusks

Neritic Zone

Oceanic Zone

• Fewer species than neritic zone

• Half of the photosynthesis that occurs on Earth takes place in oceanic zone

• Producers of the upper parts are protists and bacteria in the plankton

Oceanic Zone

• In the aphotic zone, animals feed mostly on sinking plankton and dead organisms

• Deep-sea organisms must cope with the near freezing temperature and crushing pressure

• Deep sea vents lead to adaptations from organisms -> Deep sea tube worms

Oceanic Zone

Population and Community Ecology

Chapter 35

WARM - UP

How many

species are

there?

Concept 35.1

• A population is a local group of organisms of ONE species.

• Key Terms• Population density

What is a Population?• Alligators living in a swamp

make up a population—members of the same species living in a specific geographic area.

• Other populations in the swamp include diverse species of trees, egrets and other birds, and the various species of fishes, algae, and microorganisms in the swamp water.

Defining Populations

• Several factors influence a population's size and how much it changes over time. They include the availability of food and space, weather conditions, and breeding patterns.

• In studying how these factors affect a population, ecologists need to define the population's geographic boundaries.

• Natural• Artificial

Population Density

• Population density is the number of individuals of a particular species per unit area or volume.

• The number of alligators per square kilometer of swamp, the number of bacteria per square centimeter of an agar plate, and the number of earthworms per cubic meter of soil are all examples of population density measurements.

Population density   =  Individuals  =  1000 trees  =  20 trees   Unit area  50 km2  1 km2

Sampling Techniques• It usually isn't practical to count every member of a

population. There may be too many individuals, or they may move around too quickly to be counted accurately, as with many species of insects, birds, and fish.

• In such cases, ecologists use a variety of sampling techniques to estimate the size of the population.

• Quadrats• Indirect Counting• Mark-Recapture• Limits to Accuracy

Sampling Techniques

• Quadrats• One method is to mark off a

particular area, then count the number of a particular species within this boundary

• After repeating this procedure in several locations within the ecosystem, ecologists average their results to estimate the population density of this species in the ecosystem

Sampling Techniques

• Indirect Counts• A sampling technique

for organisms that move around a lot or are difficult to see is indirect counting

• This method involves counting nests, burrows, or tracks rather than the organisms themselves

Sampling Techniques

• Mark-Recapture• The biologist traps animals in the study area and marks

them, such as with a drop of colored dye. • The researcher then releases the marked individuals.• After a period of time, the researcher again captures

animals from the population and counts the marked and unmarked individuals in the second sample.

Total population  =   # in 1st capture * # in 2nd capture  

# of marked animals recaptured

Mark-Recapture

Limits to Accuracy

• Most sampling techniques involve making some assumptions about the population being studied. If these assumptions are not valid, then the estimate will not be accurate.

• For example, the quadrat method assumes that organisms are distributed fairly evenly throughout the study area.

• The mark-recapture technique assumes that both marked and unmarked animals have the same chance of surviving and of being caught in the second capture.

Warm-Up• Charles Darwin

calculated that a single pair of elephants could increase to a population of 19 million individuals within 750 years.

• Why isn’t the world overrun with elephants?

• What type of factors may have influenced the population growth of the elephants?

Concept 35.2

• There are limits to population growth.

• Key Terms• Exponential growth• Limiting factor• Carrying capacity• Density-dependent factor• Density-independent factor

Population Dispersion

• Spatial distribution of organisms (spacing)• Clumped• Even • Random

Clumped Distribution

• Individuals are clustered together

• Occurs when resources such as food and living space are clumped together

• Occurs also with social behavior

• Fish in schools• Birds in flocks

Even Distribution

• Results from social interactions where individuals are trying to get as far away from each other as possible• Gannets staking claim

on a specific area of the coast from its neighbors

Random Distribution

• Results from seed dispersal by the wind or birds• Forests• Wildflowers

Population Dynamics

• All populations are dynamic – they change in size and composition over time

• In order to understand these changes – you need to look at:• Birth rate• Death (Mortality) rate• Life Expectancy

Birth vs. Death (Mortality) Rates

• Number of births occurring in a period of time• In the United States there are 4 million births per year

• Number of deaths occurring in a period of time• In the United States there are 2.4 million deaths per year

• The average length an individual is expected to live• In the United States in 1996, the life expectancy for a man

was 72 years, and for a woman is was 79 years

Patterns of Mortality

• The mortality rate of different species tend to conform to one of three curves on a graph

• These curves are called “survivorship curves” because they show the likelihood of survival at different ages throughout the lifetime of an organism

Survivorship Curves• Red = Type I

• Likelihood of dying is small until later in life

• Humans & elephants• Green = Type II

• Probability of dying does not change, is constant

• Bird species• Blue = Type III

• Many organisms die young, the few who survive live long lives

• Oysters, salmon, and insects

Population Growth Rate• Demographers = scientists who study population

dynamics

• Growth rate of a population = the amount by which a population’s size changes in a given time

• Whether a population grows, shrinks, or remains the same size depends on four processes.

• Birth, Death, Immigration, and Emigration

Population Growth Processes

• Birth and Immigration add to a population

• Death and Emigration subtract individuals from a population

• Birth rate – Death rate = Growth rate

Exponential Growth (J-shaped)• Population increases rapidly after

only a few generations; the larger a population gets, the faster it grows

• We can predict that the population will grow indefinitely and at an increasingly rapid rate based on this model

• Limitations = populations can only grow indefinitely with unlimited resources

Logistic Model (S-shaped)

• Builds on the Exponential Model by accounting for the influence of limiting factors

• Employs K (carrying capacity)

• The number of individuals the environment can support over a long period of time

Limiting Factors

• Factors that restrain the growth of a population• Resources depleted or

shrinking• Waste build-up• Competition among

individuals

2 Types of Limiting Factors

• Density-independent • Reduces the population by the same proportion,

regardless of the population’s size • Examples: weather, flood, fires

• Density-dependent • Resource limitations (such as food shortages or

nesting sites) are triggered by increasing population density

Population Fluctuations

• Population fluctuations are linked to environmental changes.

• Lynx and Snowshoe hares

Perils of Small Populations

• Rapidly growing human population has caused extreme reductions in the populations of some other species and subspecies

• Siberian tigers – less than 200 left in the wild due to over hunting and habitat destruction

• California condors – by the 1980’s, the condor’s wild population was down to 9 individuals

More Perils of Small Populations

• Small populations are more vulnerable to extinction due to:

• Environmental disturbances (storms, fires, floods, or diseases)

• Inbreeding – lack of genetic variability

• More susceptible to diseases and have a shorter life span

• Example: Cheetahs

Concept 35.3

• Biologists are trying to predict the impact of human growth on the world.

• Key Terms• Age Structure

Age Structure

• The distribution of individuals among different ages in a population• Populations with a high percentage of young

individuals have a greater potential for rapid growth

Population Age Structures

History of Human Population Growth• Until 10,000-12,000 years

ago the human population grew very slowly

• Hunter-gatherer lifestyle• Low population

growth rate due to small populations and high mortality rates

• Infants and young children rarely reached reproductive maturity

Development of Agriculture

• Humans learned how to domesticate animals and cultivate plants for food

• Change from hunter-gatherer to agriculturists

• Called the Agricultural Revolution

• Increase in available food supply• Human population grew faster

Population Explosion• Human population growth accelerated after

1650 because of a sharp decline in death rates

• Reason for decline:• Better sanitation• Increased availability of food• Improved economic conditions

Human Population Growth

• It took most of human history for the population to reach 1 billion (1800), however it only took 27 years (1960-1987) for the population to grow from 3 billion to 5 billion

Population Growth Today

• Even though birth rates have decreased, the population is still increasing

• 20% of the population live in developed countries• U.S., Japan, Germany, France, United Kingdom,

Australia, Canada, and Russia• Better educated, healthier, and live longer

• 80% of the population live in developing countries• Central America, South America, Africa• Poorer, populations grow much faster

The Future of the Human Population

• Human population growth will eventually stop, however we do not know when

• How large will the population be?• Will the planet be able to support

the population over a long period of time?

• The answer to these questions will depend on whether we use our resources wisely

Human Populations Lab

Demographics Lab

You can look at

cemeteries in order to document trends in human

populations

After calculating After calculating the ages, you will the ages, you will

document the data document the data on a data table and on a data table and graph your resultsgraph your results

In this lab you In this lab you will calculate the will calculate the age of individuals age of individuals

located in 4 located in 4 different plots in different plots in

a cemeterya cemetery

Concept 35.4• Species interact in biological communities.

• Key Terms• Interspecific competition• Competitive exclusion• Niche• Predation• Symbiotic relationship• Parasitism• Mutualism• Commensalism

Symbioses

• 5 Major Types of Close Interactions• Predation• Parasitism• Competition• Mutualism• Commensalism

Predation

• Predators capture, kill, and consume another individual, the prey

• Natural Selection favors adaptations that improve the efficiency of predators in finding, capturing, and consuming their prey

• Natural Selection favors adaptations that allow prey to avoid, escape, or ward off predators

Predators & Prey

• Example:• Rattlesnakes have

adaptations for locating their prey (frogs, etc) with an acute sense of smell and with specialized heat sensitive pits located below each nostril

Mimicry

• Deception is important in anti-predator defenses

• Two types of Mimicry• A harmless species resembles a

poisonous or distasteful species• Two or more dangerous species look

similar so that when a predator encounters one it will avoid similar individuals

Mimicry in action…

• Can you see the mantis in the pictures?

Mimicry in action…• The scarlet king

snake (top) mimics the pattern of the eastern coral snake (bottom) so that predators will avoid it• Scarlet King Snake =

non-poisonous• Eastern Coral Snake

= poisonous

Toxic Prey

• This poison arrow frog escapes predation because its bright colors signify a toxic taste

Plant vs. Herbivore Interactions

• Some plants develop adaptations to avoid animals that eat plants (herbivores)

• Physical defenses – sharp thorns, spines, sticky hairs, and tough leaves

• Chemical defenses – secondary compounds that are poisonous, irritating, or bad-tasting

• Strychnine and nicotine (toxic to insects)• Poison ivy and oak produce a skin-irritating substance• Drugs like morphine, atropine, codeine, taxol, and

quinine are derived from secondary compounds

Parasitism

• Species interaction that resembles predation, where one individual is harmed and the other benefits; however, the parasite feeds on the other individual (the host)

• While most forms of predation removes an organism from the population, parasitism does not result in the immediate death of the host• Often the parasite feeds off of the host for a long

time instead of killing it

Ectoparasites

• External parasites – live ON their host and do not enter the host’s body

• Examples:• Ticks• Fleas• Lice• Lampreys• Leeches• Mosquitoes

Endoparasites

• Internal parasites – live INSIDE the host’s body

• Examples:• Disease-causing

bacteria• Protists (like malaria

parasites)• Tapeworms

Parasite Adaptations

• Parasites have specialized anatomy and physiology• Example: The tapeworm doesn’t even have a

digestive system – instead they absorb nutrients through their skin

• Host Adaptations: • Skin is an important defense against parasites• Openings (eyes, mouth, and nose) are

defended chemically by tears, saliva, and mucus

Competition

• Results from a niche overlap – where resources are used by two or more species

• Interspecific Competition – species compete for the same resources• Savanna Grasslands

• First studies on competition were performed by G.F. Gause on two species of paramecia

Competitive Exclusion

• Joseph Connell’s study on barnacles (Balanus and Chthamalus)

• Two species of barnacles competing for space on the rocks

• Balanus crowded out the Chthamalus in the lower tidal zone

Competitive Exclusion

• The composition of a community may change through competitive exclusion

• Competitors may adapt niche differences or anatomical differences that lessen the intensity of competition• These differences are often greatest where

the ranges of potential competitors overlap• Called character displacement

Adaptive Radiation

• Darwin’s Finches

• Example of character displacement because their beak differences allow for them to feed on different foods and in turn reduce competition

• Resource Partitioning

Mutualism

• Cooperative relationship in which both species derive some benefit from the relationship

• Some mutualistic relationships are so close that neither species can survive without the other

• Pollination is a mutualistic relationship• Animals feed on the flower• Animal is covered with pollen and carries it to other

flowers and pollinates them

Mutualism

• Lichens • Made up of a

fungi and an algae

• Coral polyps contain dinoflagellates

Commensalism

• Commensalism is an interaction in which one species benefits and the other is not affected

• Example:• Clown Fish and Sea

Anemone

Concept 35.5

• Disturbances are common in communities.

• Key Terms:• Ecological succession• Primary succession• Secondary succession• Introduced species

Species Richness vs. Diversity

• Species Richness• The number of species a community

contains• Counts the species in a community

• Species Diversity• The number of species in a community and

the relative abundance of the species in the community

• Suggests the species’ importance because it takes into account how common the species is in the community

Patterns of Species Richness

• Varies with Latitude • The closer to the Equator = more species

• Hypotheses:• Temperate habitats are younger, due to the ice

age• Climate is more stable in the tropics• Plants can photosynthesize all year long in the

tropics, allowing more food to support more organisms

Species/Area Effect

• Larger areas contain more species than smaller areas• Larger areas usually contain a

greater diversity of habitats and can support more species

Reducing the size of the habitat reduces the number of species is can support

Species Interaction and Species Richness

• Interactions among species (Symbioses) promote species richness• Predators can prevent competitive

exclusion• Example:

• Pisaster

Pisaster vs. Mytilus

Community Stability

• Community Stability = A community’s resistance to change

• Species richness improves community stability• Grass plots with more species took less time to

recover from drought• Grass plots with more species lost a smaller

percentage of land mass than plots with less species

Succession

• Disturbances such as fires, landslides, hurricanes, and floods trigger a sequence of changes in communities

• The gradual, sequential re-growth of species in an area is called succession

Disturbances to Communities

• Large scale• Small scale

Primary Succession

• Development of a community in an area that has NOT supported life previously, such as bare rock, sand dunes, or an island formed by volcanic eruptions

• Proceeds very slowly because minerals necessary for plant growth is unavailable• Lichens• Plants• Trees• Pine, Balsam, and Spruce Forests

Secondary Succession• Sequential replacement of species that follow

disruption of an existing community• May stem from a natural disaster (forest fire or a

strong storm)• Could happen following human activities (farming,

logging, and mining)

• Commonly takes about 100 years for the original ecosystem to return through a series of well-defined stages• Annual grasses (dandelions, grasses)• Perennial grasses and shrubs• Trees• Deciduous forest

Pioneer Species vs. Climax Community

• Pioneer Species• The species that predominates early in

succession• Tends to be small, fast-growing, and fast-

reproducing

• Climax Community => Stable End Point• The organisms in each stage alter the physical

environment in ways that make it less favorable for their own survival, but more favorable for the organisms that succeed them

Human Activities & Species Diversity

• Clearing the Land• Forests cleared for

farmland or housing

• Introduced Species• Kudzu – introduced

to help stop erosion• Grew out of control

and took over the landscape

Ecosystems and Conservation Biology

Chapter 36

Concept 36.1

• Key Terms• Producer• Consumer• Decomposer• Trophic level• Food chain• Herbivore

• Carnivore• Omnivore• Primary consumer• Secondary

consumer• Tertiary consumer• Detritus• Food web

Feeding relationships determine the path of energy and chemicals in the ecosystems.

Energy Flow & Chemical Cycling

Concept 36.2

• Energy flows through ecosystems.

• Key Terms• Biomass• Primary productivity• Energy pyramid• Biomass pyramid• Pyramid of numbers

Energy Flow

• Energy is passed from one organism to another in the ecosystem

• In order to follow the energy flow we group organisms based on how they obtain energy• Trophic Levels

Trophic Level

• The organism’s position in the sequence of energy transfer

• Most ecosystems contain only 3-4 trophic levels

Energy Transfer

• Food Chain• Single pathway of feeding

relationships • Ex. Grass seeds -> Mouse -> Snake ->

Hawk

• Food Web• Linking of 2 or more food chains

Food Chains

Food Webs

Energy Pyramid

Biomass Pyramids

Output Assignment

• Design 3 Food Chains • Must have at least 3 individual organisms

• Incorporate those 3 Food Chains into a Food Web

• Create a meal for a human that incorporates 2 different Trophic levels

Concept 36.3

• Chemicals cycle in ecosystems.

• Key Terms• Nitrogen Fixation• Nitrification• Transpiration

KWLH Chart – Output WarmUp

• Before Taking Notes:

• Write down 3 things you KNOW about any of the biogeochemical cycles

• Write down 3 things you WANT to find out about the biogeochemical cycles

Ecosystem Cycles

• Energy flows through the ecosystem and is recycled and reused

• Each substance travels through a biogeochemical cycle• Water Cycle• Carbon Cycle• Oxygen Cycle• Nitrogen Cycle

Basic Pattern of Chemical Cycling

• Producers incorporate chemicals from the non-living environment into organic compounds

• Consumers feed on the producers, incorporating some of those chemicals into their own bodies and releasing some back into the environment as waste products

• As organisms die, decomposers break them down, further supplying the soil, water, and air with chemicals in inorganic form

Water Cycle

• Cells contain 70-90% water

• Found in a number of places in the environment • Cells• Ground water• Water vapor in the atmosphere

• Evaporation• Adds water to the atmosphere as water vapor• Heat causes water to evaporate from bodies of

water, the soil, and living things

• Transpiration• Plants take in water through their roots and it

is released from their leaves into the atmosphere

• Animals drink water and then release it when they breathe, sweat or excrete

• Precipitation• Water is leaving the atmosphere via rain,

snow, sleet, hail or fog

Carbon-Dioxide & Oxygen Cycles

• Two processes...• Photosynthesis

• Plants and other autotrophs use carbon dioxide with water and sunlight to make carbohydrates

• Cellular Respiration• Autotrophs and Heterotrophs use oxygen to

break down carbohydrates into water and carbon dioxide

Human Influence on the Carbon Cycle

Burning fossil fuels adds carbon dioxide into the atmosphere+

Destruction of vegetation (clear-cutting)=

Less carbon cycling

Nitrogen Cycle

• All organisms need nitrogen to make proteins and nucleic acids• Plants absorb nitrates from the soil• Animals obtain nitrogen by eating

plants and digesting the proteins and nucleic acids

• 78% of the atmosphere = Nitrogen

Nitrogen Cycle…• Nitrogen Fixation

• Converts nitrogen gas to nitrate• Nitrogen-fixing bacteria convert N2 gas

into ammonia, then nitrite, then nitrate, which plants can use

• Ammonification• Decomposers break down the corpses

and wastes of organisms and release the nitrogen that they contain as ammonia

Nitrogen Cycle…

• Nitrification• Bacteria in the soil take up ammonia

and oxidize it into nitrites and nitrates

• Denitrification• Anaerobic bacteria break down

nitrates and release nitrogen gas back into the atmosphere

KWLH Chart – Output WarmUp

• After Taking Notes:

• Write down 3 things you LEARNED about the biogeochemical cycles

• Write down 3 ideas of HOW we can learn more about the biogeochemical cycles

Concept 36.4

• Human activities can alter ecosystems.

• Key Terms• Deforestation• Greenhouse effect• Global warming• Eutrophication• Acid rain• Pollution• Biological magnification• Ozone

Impact on Chemical Cycles

• Human activities can affect chemical cycles by moving the nutrients from place to place

• Deer – eats plants in a forest and returns the waste to the same location

• Humans – eat a salad and then their waste may be carried out to the ocean

Carbon Cycle Impacts

• Burning of wood and fossil fuels increase carbon dioxide in the atmosphere

• Deforestation – eliminated plants that use carbon dioxide for photosynthesis

• Greenhouse effect – process in which atmospheric gases trap heat

• Global warming – overall rise in Earth’s temperature

Greenhouse Effect

Nitrogen Cycle Impacts

• Human activities move large portions of nitrogen into the water or air

• Eutrophication• Fertilizer runs off into a water source causing

algae blooms

• Acid Rain• Nitrogen and Sulfur combine to create acid rain

in the atmosphere

Eutrophication

Acid Rain

Water Cycle Impact

• Deforestation – Removes trees that return water to the atmosphere through transpiration, reduces the amount of water vapor and changes precipitation patterns

Other Effects of Pollution

• Pollution – addition of substances to the environment that results in negative effects

• Biological Magnification

• Damage to the Ozone Shield

Biological Magnification

• Gradual accumulation of chemicals inside of an organism because it cannot excrete the pollutants

• DDT• Used to combat mosquitoes• Accumulates in fat cells (lipids) and is

magnified through the food chain

PCB’s & DDT

Damage to the Ozone

• Some pollution affects a gas called ozone (O3) to break down

• A major contributor to the destruction of the ozone are chloroflurocarbons (CFCs) released from aerosol cans, refrigeration units, and manufacturing processes

Ozone Hole & CFC’s

DDT DebateAre the benefits of DDT worth the costs?

Roles of the debater:

1. Environmentalist - environmental stance on DDT use

2. Govt. Official in charge of Environmental Policy

3. World Health Organization investigating Malaria and other mosquito-based disease Prevention

Warm-Up• Brainstorm 3-5 past/present

products that are derived from threatened species.• Ex. Taxol, a cancer drug,

derived from yew trees threatened by deforestation

• Ex. Ivory for piano keys or jewelry, comes from elephants threatened by overhunting

• Step beyond blaming humans for evil/greed:• Why can protecting

threatened species be a tough issue to solve?

Concept 36.5

• Conservation biology can slow the loss of biodiversity.

• Key Terms• Biodiversity• Overexploitation• Conservation biology• Zoned reserve• Buffer zone• Sustainable development

Conservation & Biodiversity• Conservation = protecting and sustaining

resources for the future

• Biodiversity = • Variety of life on Earth• Variety of ecosystems in the biosphere• Genetic variety among individuals in a

species

• Why does it matter?• Because EVERYTHING is connected!• If one species was to disappear – it would

affect the entire ecosystem!

Biodiversity: Importance to Humans

• Source of beauty/inspiration

• Oxygen, food, clothing, and shelter

• Aids in the development of medicines• 25% of medicine in the U.S. contain substances from

plants

• Possibility of discovering new products for human use

• Rosy periwinkle – yields a medicine used to treat 2 forms of cancer (childhood leukemia & Hodgkin’s disease)

• Deforestation in Madagascar threatens this species

Mass Extinctions

• There are periods in Earth’s history where mass extinctions caused a number of species to become extinct

• Signs of another mass extinction taking place:

• ~11% of the 9,040 known bird species in the world are endangered

• Of the ~20,000 known plant species in the U.S., at least 680 species are endangered

• ~20% of the world’s freshwater fish have either become extinct or are endangered

Threats to Biodiversity

• Conservation Biologists use the acronym HIPPO to summarize global threats to biodiversity• H = Habitat Destruction• I = Introduced Species• P = Pollution• P = Population Growth• O = Overexploitation

Habitat Destruction• As the human population grows –

more land is needed for agriculture, roads, and communities

• If an organism that required that habitat does not adapt or move - it will not survive

• Some changed to a habitat causes it to be fragmented (building a road through a forest) preventing species from using resources in all parts of the forest

Introduced Species• Introduced (non-native)

species often prey on native species or compete with them for resources

• Starlings and House Sparrows competing with native Bluebirds

Overexploitation

• The practice of harvesting or hunting to such a degree that the small number of remaining individuals may not be able to sustain the population

• Examples:• Over-fishing• Poaching

Conservation Biology Approaches

• Goals of Conservation Biology• Finding solutions• Carrying out the solutions

• Possible Approaches• Focusing on hot spots• Understanding an organism’s habitat• Balancing demands for resources• Planning for a sustainable future

Hot Spots

• Earth’s biodiversity “hot spots” are home to an enormous variety (2/3 of ALL plant and vertebrate) of species, many of which are endangered.

• Biodiversity hot spots also tend to be “hot spots” for extinction – this makes them a top priority with conservation biologists, lawmakers, and local communities working together to preserve those locations.

Understanding Habitats

• Understanding the habitat requirements of a species can help biologists manage its existing habitat or create new habitat areas• Red-Cockaded

Woodpecker

Balancing Demands for Resources

• In many cases a tug-of-war exists between efforts to save species and the economic and social needs of people • Should a wooded habitat be conserved in an

effort to save an owl population if it means putting hundreds of loggers out of work?

• Remember the DDT debate?

• Politicians, townspeople, and conservation biologist can reach resolutions by reviewing scientific data, weighing costs and benefits, looking for alternative solutions, and casting their votes.

Planning for a Sustainable Future

• Costa Rica has established 8 zoned reserves in an effort to conserve biodiversity while meeting the needs of humans

• People live and work in the buffer zones surrounding the park reserves

Planning for a Sustainable Future

• Many nations, scientific organizations, and private foundations are working toward a goal of sustainable development – developing natural resources so that they can renew themselves and be available for the future.

• The challenge for individuals and nations is to find a way to meet the needs of Earth’s human population, while conserving ecosystems and resources for the planet’s other populations as well.

Output – Conclusion

• What types of things could you do in your life that will impact the environment in a positive way?