Principles of EcologyChapter 2

Please complete the handout at your desk You have 10 minutes

Do Now

Ecology—the scientific study of organisms and their interactions with the environment

Studies relationships of living and nonliving parts

What kinds of questions might an ecologist ask?

Organisms and Their Environment

Ecologist would study:◦ What it eats◦ Where it lives◦ What other organisms it interacts with◦ Patterns of dispersion◦ What eats it◦ Disease◦ Impact on environment◦ And more

Example: Cow

Biosphere—the portion of Earth that supports life

The Biosphere

The non-living components of an environment

Examples:◦ Rocks◦ Air◦ Temperature◦ Light◦ Moisture

Abiotic Factors

The living parts of an environment, including the organisms themselves

Examples:◦ People◦ Plants◦ Animals◦ Fungi◦ Bacteria

Biotic Factors

Organism Population—a group of organisms of the same

species within the same geographic location Biological Community—a group of interacting

populations that occupy the same area at the same time

Ecosystem—a biological community and all of its abiotic factors

Biome—a group of ecosystems of the same climate and types of communities

Biosphere

Levels of Organization

A habitat is a place where an organism lives

An ecological niche is the role and position of an organism within its environment

Habitats and Niches

Organisms or species cannot occupy the same exact ecological niche at the same time

Why???

https://www.youtube.com/watch?v=xIVixvcR4Jc

A Word about Niches

Sym= Together

Bio= Living

Symbiosis is close association between two or more organisms

There are a few key types of symbiotic relationships

Symbiosis

A type of symbiotic relationship where one organism clearly benefits because it is living at the expense of another (+/-)

Parasitism

Both organisms in the relationship benefit

(+/+)

https://www.youtube.com/watch?v=dJRJCO59bf4

Mutualism

One organism benefits and the other is not affected (+/0)

Example: Sea anemone and clownfish

Commensalism

Autotrophs are organisms that use energy from the sun to manufacture their own nutrients

Literally means “self feeder”

Heterotrophs are organisms that must feed on other organisms and cannot make their own food

Energy in Ecosystems

Herbivore—eats plants

Carnivore—meat eaters

Omnivore—eats all

Detritivore—eats dead organic material

Types of Heterotrophs

A food chain is a simple model that shows how energy flows through an ecosystem◦ GrassCowHuman

Food Webs are models representing interconnected food chains in which energy flows through a group of organisms

Trophic Levels are steps in the food web or chain

https://www.youtube.com/watch?v=Cd1M9xD482s

Food Chains and Webs

Levels of energy passage

Trophic Levels

Plants= producers

Animals who cannot make their food are primary, secondary, tertiary, and quaternary consumers

Then there are the detritivores

Trophic Levels

Figure 42.4

Sun

Heat

Primary producers

Primaryconsumers

Detritus

Secondary andtertiary

consumers

Microorganismsand other

detritivores

KeyChemical cyclingEnergy flow

Energy PyramidTertiaryconsumers

Secondaryconsumers

Primaryconsumers

Primaryproducers

10 J

100 J

1,000 J

10,000 J

1,000,000 J of sunlight

Figure 42.11

Trophic level

Tertiary consumersSecondary consumers

Primary consumersPrimary producers

(a) Most ecosystems (data from a Florida bog)

(b) Some aquatic ecosystems (data from the English Channel)

Trophic level Dry mass(g/m2)

Dry mass(g/m2)

1.51137

809

421Primary consumers (zooplankton)

Primary producers (phytoplankton)

Biomass Pyramids

Pyramid of Numbers

Biogeochemical Cycles Nutrient cycles in ecosystems involve biotic and

abiotic components and are often called biogeochemical cycles

Common cycles include◦ Carbon◦ Oxygen◦ Sulfur◦ Nitrogen◦ Phosphorus◦ Water

The Water Cycle Water is essential to all organisms Liquid water is the primary physical phase in which

water is used The oceans contain 97% of the biosphere’s water;

2% is in glaciers and polar ice caps, and 1% is in lakes, rivers, and groundwater

Water moves by the processes of evaporation, transpiration, condensation, precipitation, and movement through surface and groundwater

The Nitrogen Cycle Nitrogen is a component of amino acids, proteins,

and nucleic acids The main reservoir of nitrogen is the atmosphere

(N2), though this nitrogen must be converted to NH4+

or NO3− for uptake by plants, via nitrogen fixation by

bacteria Nitrogen fixation is conversion of unusable forms of

nitrogen into forms that plants and animals can use Denitrification is when fixed nitrogen is converted

back into atmospheric nitrogen

Figure 42.13c

The nitrogen cycle

Fixation

Denitrification

Runoff

N fertilizers

Reactive Ngases

Industrialfixation

N2 inatmosphere

NO3−

NH4

Dissolvedorganic NNO3

−

Aquaticcycling

Decompositionand

sedimentation

Terrestrialcycling

Fixationin root

nodules

Decom-position

N2

NO3−

NH4

Ammoni-fication

Assimilation

Denitri-fication

Uptake ofamino acidsNitrification

Go to page 53

Respond to the “Constructed Response” questions

#9, 10, 23, 34, 35

Chapter 2 Assessment

Classwork Take a look at each of the cycles starting on

page 46 of your textbook◦ Water◦ Carbon/Oxygen◦ Nitrogen◦ Phosphorus

Draw a simplified diagram of each of the four cycles and annotate it for your notes

Communities, Biomes, and Ecosystems

April 25, 2014

Take 8 minutes to look over your notes for the quiz

HINT: It might be helpful to know how to make a cladogram

If you talk during this time, you lose this time, so use it wisely

Do Now

What is YOUR community?

Community Ecology

A community is a group of interacting populations that occupy the same area at the same time

It is not restricted to a single species or population, its all of the living things in the area

Communities

How can communities vary?

Could an organism survive in just any community? How does this tie into ecological niche?

What do you think?

Limiting factors are biotic or abiotic factors in an ecosystem or community that restrict the numbers, reproduction, or distribution of organisms

Can you think of any??

Limiting Factors

Sample Limiting Factors

Abiotic Factors Biotic Factors

Sunlight Temperature Water Nutrients Fire Soil Chemistry Available Space

Other living things

Every organism has an upper and lower limit for each limiting factor

The ability of an organism to survive when it is subjected to biotic or abiotic factors is called tolerance

Tolerance

Tolerance

A fire burns down a forest?

A volcano erupts and flows over fertile land?

Humans clear forests for lumber?

What happens when…?

Ecological succession is the change in an ecosystem that happens when one community replaces another as a result of changing abiotic and biotic factors

Primary succession occurs in areas in which there is no layer of topsoil

Secondary succession is the orderly and predictable change that occurs after a community or organisms have been removed but the soil has remained intact

Ecological Succession

Climax communities occur when there is little change in the composition of a species

Climax Communities

Weather is the condition of the atmosphere at a specific place and time

Latitude is the distance at any point of the Earth north or south from the equator

Climate is the average weather conditions in an area, including temperature and precipitation

Weather and Climate

Freezing temperatures Treeless Covered by layer of permafrost Contains some animals and shallow-rooted

plants

Biomes: Tundra

South of the tundra Evergreens Slightly warmer than tundra with longer

summers No permafrost layer Used to be called taiga

Boreal Forest

Cover southeast Canada, eastern US, most of Europe, and parts of Asia and Australia

Composed of mainly deciduous (broad-leafed) forest

Has all four seasons

Temperate Forest

Open woodlands and mixed shrub communities

Less rainfall than temperate forest Occurs in Mediterranean, west coasts of

North and South America, South Africa, and Australia

Temperate Woodland and Shrubland

Fertile soils Thick cover of grasses Found at middle latitudes No large trees Infrequent rainfall

Temperate Grassland

Exists on every continent except Europe Any area in which the annual rate of

evaporation exceeds the annual rate of precipitation

Sometimes resemble traditional desert, but sometimes do not

Desert

Grasses and scattered trees Less rainfall than other tropical areas Mostly in Africa, Australia, and South

America

Tropical Savanna

Very dry Almost all trees drop leaves in the dry

season to conserve water

Tropical Seasonal Forest

Warm temperatures Large amounts of rainfall Central and South America Dense in biomass Much biodiversity

Tropical Rain Forest

Border tundra Cold all year Site of polar ice caps

Polar Regions

Water on Earth

Population Ecology

Members of the same species living and interbreeding in the same area

Population density—the number of organisms per unit area

Dispersion—the pattern of spacing of a population within an area

Populations

Patterns of Dispersion Environmental and social factors influence the

spacing of individuals in a population The most common pattern of dispersion is

clumped, in which individuals aggregate in patches

A clumped dispersion may be influenced by resource availability and behavior

There is also uniform in which individuals are evenly distributed in an area

Random distributions do not exhibit a pattern

Figure 40.15

(a) Clumped

(c) Random(b) Uniform

Figure 40.15d

(a) Clumped (c) Random(b) Uniform

What Limits Population Size? Density-Independent Factors are factors

in the environment that do not depend on the members of the population per unit area◦ Usually abiotic◦ Examples?

Density-Dependent Factors are factors in the environment that depend on the number of members in the population per unit area◦ Examples?

Population Size

Change in population size can be defined by the equation

If immigration and emigration are ignored, a population’s growth rate (per capita increase) equals birth rate minus death rate

− −Change inpopulation

sizeBirths

Immigrantsentering

populationDeaths

Emigrantsleaving

population

Exponential Population Growth Exponential population growth is population

increase under idealized conditions Under these conditions, the rate of increase is at

its maximum and increases rapidly

Figure 40.17

1,000

Number of generations

Popu

lati

on s

ize

(N) 1.0N

100

0 155

2,000

1,500

500

0.5N dt dN

dt dN

Carrying Capacity Exponential growth cannot be sustained for long in

any population A more realistic population model limits growth by

incorporating carrying capacity Carrying capacity (K) is the maximum population

size the environment can support

Logistic Growth: Takes Carrying Capacity into Account In the logistic population growth model, the per

capita rate of increase declines as carrying capacity is reached

The logistic model starts with the exponential model and adds an expression that reduces rate of increase as population size approaches K

Figure 40.19

1,000

Number of generations

Popu

lati

on s

ize

(N) 1.0N

100

0 155

2,000

1,500

500

1.0N

dt dN

Exponentialgrowth

Population growthbegins slowing here.

K 1,500

dt dN (1,500 N)

1,500

Logistic growth

R vs K Selection

Fast versus slow Fast reproductive strategies are known as

R-strategies

Slow Reproductive strategies are called the K-strategy

R-selection (Quick and many Eg. Mice and rabbits)

K-selection (slow and few Eg. Elephants, whales, humans)

Slow (K) vs Fast (r) Large body size

Long life span

Take a long time to sexually mature

• Small body size

• Short life span

• Sexually mature very quickly (weeks to months)

Typically carry 1-2 young

Protect and nurture their young

High survivorship (type 1) of species over time.

Slow (K) vs Fast (r)• Carry/hatch many

young• Must care for

themselves at an early age

• Low Survivorship of young (many die) – type 3

https://www.youtube.com/watch?v=yTLX89_Llxg

Human Population Growth

Write the following words on a BRAND NEW sheet of paper:◦ Flood◦ Starvation◦ Disease◦ Earthquake◦ Predation◦ Space

Circle the density dependent factors Underline the density independent factors You have 5 minutes

Do Now

Population Swap!

Biodiversity and Conservation

Extinction is when the last member of a species dies

Biodiversity is the variety of life in an area that is determined by the number of different species in that area

Some Vocab

Types of biodiversity◦ Genetic◦ Species◦ Ecosystem

Economic Value Health Maintaining Ecosystems Aesthetics Science

Biodiversity=Ecosystem Stability

Background extinction—gradual process of species becoming extinct

Mass extinction—when a large percentage of all living things become extinct

Lack of natural resources Overexploitation Habitat Loss Habitat Fragmentation

Threats to Biodiversity

When an overabundance of nutrients (usually N or P) in an ecosystem cause overgrowth of microorganisms and/or algae and upset the balance of an ecosystem

Eutrophication

The increasing concentration of toxic substances in organisms as trophic levels increase in a food chain or food web

So what does this mean??

How does it happen??

Biomagnification

Non-native species that are either intentionally or unintentionally transported to a new habitat

What does this mean for ecological niches?

Kudzu Zebra Mussel

Introduced Species

Restoration Ecology Restoration ecology seeks to initiate or speed up

the recovery of degraded ecosystems Bioremediation is the use of organisms to

detoxify ecosystems The organisms most often used are prokaryotes,

fungi, or plants These organisms can take up, and sometimes

metabolize, toxic molecules Biological augmentation uses organisms to add

essential materials to a degraded ecosystem

Figure 42.15

(a) In 1991, before restoration In 2000, near the completion ofrestoration

(b)

Biodiversity and Bill Nye https://www.youtube.com/watch?

v=iFeRFmqFChQ