APES Ch. 3, part 1

Hey APES

Any more lab reports?

Ch. 3, continued.

Color?

Ecosystems: What are they and how do they

work?Ch. 3

Miller and Spoolman, 16th ed.

Big Idea # 1

Ecology is the study of how organisms interact with each other and with their environment.

Organization of Life

All living things are made of 1 or more cells


A population is members of the same species, that live in a particular place at a particular time

Who, where, when The variation among

members of a population is due to its genetic diversity (DNA)


A community is all the populations in an area

Populations in a community interact with each other Feeding

relationships, competition, nutrient cycles, etc


An ecosystem is the community plus all the abiotic factors in the area

Biotic - living or recently living

Abiotic - nonliving


The biosphere is all the ecosystems…our whole world…where we all live

Cells All living things are

made of one or more cells…

You should know the basics about cell types

Cell types

There are 2 basic cell types: prokaryotic & eukaryotic

Prokaryotic Cells

Most simple BACTERIA & Archaea

Protein construction and energyconversion occur without specializedinternal structures

DNA (no nucleus)

No nucleus No organelles DNA, ribosomes,

cell wall, cell membrane

VERY DIVERSE & SUCCESSFUL

FOUND EVERYWHERE

Eukaryotic Cells Larger More complex Nucleus for DNA

Nucleus(DNA)

Proteinconstruction

Energyconversion

Specialized organelles Plants, animals, fungi,

protists

Animals and some protists do not have cell walls

Summary Check

What are the biological levels of organization? (say it)

Venn diagram: prokaryotic vs. eukaryotic cells (put it in your notes)

Big Idea # 2 Life is sustained

by 3 things: The flow of

energy from the sun through the biosphere

The cycling of nutrients within the biosphere

gravity

4 Spheres of Life

All 4 spheres interact with each other

We need all four to keep us alive

1.

3.

4.

2.

Sphere 1 - the atmosphere Atmosphere = Thin

layer surrounding the earth’s surface

Closest to land is the troposphere (ground level to 4-11 miles up) Has most of our air

Air is: 78% N2

21% O2

1% methane, CO2, H2O - greenhouse gases

The Atmosphere, cont’d

Next layer up is the stratosphere (11-31 miles) Has ozone

layer - filters out most UV radiation

Sphere 2 - the hydrosphere

Hydrosphere = all the water on earth Liquid (on surface and

underground) Solid (ice) Water vapor (in

atmosphere)

Most in oceans - covers ~ 71% of the planet

Sphere 3 - the geosphere Geosphere =

super hot core, thick, fluid mantle, thin outer crust

Contains our fossil fuels and minerals (nonrenewable) and soil nutrients (renewable)

Sphere 4 - the biosphere

All the living things on earth Life exists from ~ 6 miles above the

earth’s surface to the bottom of the ocean

Biomes Large regions of

land that have characteristic climate and species adapted to them

Terrestrial Biomes Tropical forest Savanna Desert Chaparral Temperate

grassland

Temperate broadleaf forest

Coniferous forest Tundra Taiga High mountains Polar ice

Terrestrial Biomes Vertical stratification important Plants provide the stratification

Canopy Low trees Shrubs Litter layer (forest floor)

Many organisms

adapted to a particular

layer

Terrestrial Biomes Don’t have clear, defined boundaries Ecotone - area where one biome

grades into another Find different organisms here

Summary Check

What is a biome? What biome do you live in?

Biomes Also aquatic life zones

Freshwater - lakes, rivers, streams Marine - oceans, coral reefs, estuaries

The environment limits the distribution of species

– or – not everyone can live everywhere Dispersal – movement out

of a high density area Natural range expansions Species transplants –

intentional or accidental introduction of a species to a new area Actual range vs. potential

range

Climate Major components:

Temperature Water Sunlight Wind

Macroclimate – global/regional Microclimate – very small (like under a fallen log)

Macroclimate Affected by

Water Large bodies

of water have a moderating effect

Currents carry warm or cold air

Climate Affected by

Mountains Windward vs. leeward sides

Climate Affected by

Seasonality Due to changing angle of sun Causes turnover in lakes that mixes water - essential for

life

Summary Check

How might climate affect the evolution of species over time?

The Flow of Energy

It all starts with the sun

Ozone layer absorbs 95% of incoming solar radiation

The Flow of Energy

Sunlight that does reach the surface warms the planet, drives the water cycle, generates wind

The Flow of Energy

Less than 0.1% of incoming solar radiation used by plants and protists for photosynthesis

The Greenhouse Effect Heat radiated up off

the surface of the earth makes the greenhouse effect

Yay! Makes life possible on earth

The heat increases the kinetic energy of the greenhouse gases, thus raising their temperature

Big Idea # 3 Ecosystems are

made up of both biotic and abiotic components including producers, consumers, and decomposers

Populations thrive under different conditions

Every population has a range of tolerance - variations within the preferred chemical and physical environment

Populations are affected by limiting factors

Limiting factors affect the number of organisms in a population

Too much or too little of any abiotic factor can be a limiting factor

1.1. What are some abiotic factors? What are some abiotic factors? 2.2. Use one abiotic factor to explain a Use one abiotic factor to explain a

situation in which too much or too little situation in which too much or too little of it limits population growth, even if all of it limits population growth, even if all other factors are in the range of other factors are in the range of tolerancetolerance

Density-Dependent Factors

• Competition for resources

• Predation

• Parasitism

• Disease

• Poisoning

Density-Independent Factors

• Natural disasters

• Global warming ?

• Ozone depletion ?

Density Controls

Summary Check

What are some limiting factors that would affect a population of: Polar bears? Butterflies? Humans?

Trophic Levels

Trophic level = feeding level

3 main types: Producers Consumers Decomposers

Producers Producers - aka autotrophs Self- feeders Mostly plants Also algae (protists) and plankton

in water Make their own food through

photosynthesis (use CO2 and sunlight)

Some do chemosynthesis - bacteria in deep ocean (use H2S & heat)

START ALL FOOD WEBS

6CO2 + 6H2O + light energy C6H12O6 + 6O2

Consumers

Consumers - aka heterotrophs

Consume producers or other organisms for energy

Several levels

Levels of Consumers Primary Consumers

(herbivores) - the first consumers in a food web - they eat producers

Examples: rabbits, cows, horses, some birds, grasshoppers, etc

Levels of Consumers

Secondary Consumers - omnivores (eat both plants and animals) and carnivores (only eat other animals They eat the

primary consumers

Levels of Consumers

Tertiary (and beyond) consumers - omnivores and carnivores They eat the

secondary consumers

Levels of Consumers

Decomposers - 99% are bacteria and fungi Consumer dead organisms

to get their energy Feed by secreting enzymes RETURN NUTRIENTS IN

THE ORGANISMS TO THE EARTH!

Levels of Consumers

Detritivores - aka detritus feeders or scavengers Feed on wastes or dead organisms

Summary Check

So what’s the difference between decomposers and detritivores?

Levels of Consumers

Organisms can occupy more than one level

How we harvest that energy Both producers and consumers go

through respiration to harvest the energy from their food

Aerobic - uses oxygen, needs mitochondria

Anaerobic - does not need oxygen or mitochondria

We store the energy from our food as ATP molecules

Summary Check

What does a food web diagram show? What is the ultimate source of energy

for most ecosystems? What is the exception to the second

question?

Big Idea # 4

Energy flows through ecosystems in food webs

Energy is lost as it flows from one tropic level to the next

Plants, animals, and decomposers make up

food chains A food chain is a pathway that tells us

what eats what Food chains are over-simplified models of

nature

Food webs

A food web is more realistic

It shows us how several food chains overlap and connect to each other

Limits on Food Webs A food web can

only go so far It usually does

not go beyond the level of tertiary or quaternary consumer

EnergyWhy?

It’s all about energy! Every time energy is

passed from one organism to another, some of that energy is lost

The amount of energy transferred from one level to the next is called ecological efficiency

Ecological efficiency varies, but a good rule of thumb is 10%

This means 90% of the energy is lost and only 10% makes it to the next level

Why only 10%?

1. Not everything gets eaten There may be 1000 pounds of clover in a

field, but the rabbit does not eat it all Good thing, too, or else there would be no

clover left to make new clover

2. Not everything that is eaten gets digested In other words,

some of what you eat is lost as waste (poo).

Some animals actually eat their own poo to get some more nutrition out of it! Ew.

3. The most important reason: energy is always being lost as HEAT

Whenever something does WORK, it creates HEAT

Your body is always working (heart beat, breathing, etc)

New energy must constantly enter the

system

Since energy is always being lost, new energy is always needed.

This energy comes from the sun (which feeds the grass, which feeds the cow, which feeds the person, etc.)

Energy Pyramids

We can show how energy is lost at each stage of a food web in an energy pyramid.

In an energy pyramid: Producers

are at the bottom, because they have the most available energy. (They got it right from the source)

The next level is the primary consumers. They got 10% of the energy in the plants.

Since only 10% of the energy moves on, it takes a lot of producers to support the primary consumers.

The next level is the secondary consumers. They got 10% of the energy in the primary consumers.

It takes a lot of primary consumers to support a secondary consumer

Energy Pyramid Practice

If there is 10,000 kcal of energy available in the plants at the bottom of the pyramid, how much energy will make it to the zebras, and how much will make it to the lion?

10,000

1000

100

An energy Pyramid

Gets smaller as it goes up since there is less and less energy as you go up

Pyramid of Pyramid of numbersnumbers

How many organisms are at each level

Usually mostly producers, then primary consumers, then secondary and so on

100,000 plants

1000 voles

1 owl

Pyramid of Pyramid of numbersnumbers

Could look like this:

1 oak tree supports lots of primary consumers, which support fewer secondary consumers, then even fewer tertiary, etc.

1 oak tree

1000 caterpillars

50 bluetits

1 sparrow hawk

Pyramid of Pyramid of biomassbiomass

How much everything weighs at each level

Always pyramid shaped

Interdependence

All living things are connected to other living things, both directly and indirectly. Living things eat and/or

get eaten Living things obtain

chemicals that came from other living things

The actions of living things affect other organisms

GPP and NPP Gross Primary Productivity – all the

light energy that is converted to chemical energy in an ecosystem Not all of this is available to

consumers though, because the plants need some for themselves

Net Primary Productivity – the chemical energy available to consumers

NPP Expressed as:

Energy per unit area per unit time (J/m2/yr)

Biomass of vegetation added to the ecosystem per unit area per unit time (g/m2/yr) Not the total biomass

– the amount added Total biomass called

standing crop Forests have high

total biomass, but relatively low NPP

Ecosystems with high NPP Tropical rain forests Estuaries Coral reefs Open ocean (just because so much of the

planet is covered in it)

Aquatic Ecosystems and NPP Light is important but…

Nutrients are more important Nitrogen and phosphorus

Tend to be low in photic zones and high in aphotic zones

Upwelling brings

these nutrients up

and increases NPP

Fertilizers and sewage runoff bring nutrients in to aquatic ecosystems

Too much nitrogen and phosphorus leads to algal blooms and high numbers of cyanobacteria This leads to eutrophication Depletes water of oxygen and thus most

life

Summary Check

Choose 1 word to represent what this chapter is about.

Explain why you chose that word. Be thorough in your explanation.

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APES Ch. 3, part 1