Ecosystem Ecology Ecosystems: What Are They and How Do They Work?

Date: October 26, 2015

Reminders: Print out unit 5 notes & do vocabulary

Agenda:

Review FRQ Practice/Highlight & turn in tomorrow

Review Unit 4 Test & Pass papers back

Read Chapter 4 & first 20 power point slides

Ecology: Levels • Multiple levels of ecology:

• Organisms

• Populations: groups of individuals of same species in same place

• Communities: populations in same place

• **Ecosystems: community interacting with environment

• Biosphere: parts of earth’s air, water, and soil where life is found

Ecology • Ecosystems

survive on

the:

• FLOW of

energy

• CYCLING

of matter

Ecology: Three Important Factors

Life depends on 3 interconnected factors:

1. The one-way flow of energy from the sun organisms the environment as heat back out into space as heat (open system)

Governed by laws of thermodynamics!

2. The cycling of matter through parts of the biosphere (closed system)

3. Gravity: allows the planet to hold onto its atmosphere and enables movement of chemicals in their matter cycles

Ecology: Ecosystems

Ecosystems Have Living and Nonliving Components Abiotic: nonliving component Water Air Nutrients Rocks Heat Solar energy

Biotic Living and once living Plants, animals, microbes

• Producers & Consumers Are the Living Components of

Ecosystems

• Each assigned a trophic level (feeding level)

• Producers aka autotrophs are the 1st trophic level

• Producers / autotrophs make the nutrients they

need from compounds and energy from their

environment

• Perform Photosynthesis:

• Or Chemosynthesis: make nutrients without sunlight

(specialized bacteria can do this; hydrothermal

vents)

• Autotrophs/producers are found at the bottom of

the “food chain” – have the most energy

• Types of Autotrophs:

• Terrestrial:

Nonvascular plants: Mosses

Vascular plants: Ferns, Gymnosperms (conifers),

Angiosperms (flowering plants)

Some algae (not plants, are protists!)

• Aquatic:

Phytoplankton: = floating producers

Algae (diatoms, seaweed)

Cyanobacteria

Freshwater & marine plants

http://www.planktonch

ronicles.org/en/episod

e/plankton

• Consumers aka heterotrophs: must

consume other organisms for energy (and

nutrients)

• Primary consumers = eat autotrophs

• Secondary consumers = eat the autotroph-

eaters

• Tertiary consumers = eat the eaters of the

autotroph-eaters

Types of Heterotrophs:

Herbivore (Ex: elephants, caterpillars, zooplankton) Energy/nutrients from plant/algae material

Carnivores (Ex: spiders, lions, fish) Energy/nutrients from animals/meat

Omnivores (Ex: pigs, rats, bears, humans) Energy/nutrients from both plant and animal matter

Types of Heterotrophs continued:

Scavengers (Ex: vultures, hyenas) Energy/nutrients from large pieces of dead and decaying

animal/meat

Detritivore (Ex: worms, insects, small crabs) Energy/nutrients from medium pieces of dead organic

matter (plant or animal)

Types of Heterotrophs continued:

Decomposers: consumers that digest on a molecular scale & release nutrients (BUT NOT ENERGY!) back into the environment

Includes: Bacteria & Fungi

Are present basically at every trophic level

• Both Producers & Consumers Perform Respiration

• Aerobic respiration: making energy from sugar in the presence of oxygen

• Anaerobic respiration/ fermentation: energy gained in absence of oxygen. End products include methane gas (CH4), ethyl alcohol, acetic acid, and hydrogen sulfide

ATP

• As energy flows through ecosystems in food

chains and webs, the amount of chemical

energy available to organisms at each

succeeding trophic level decreases. • Food Chain: One way-flow of energy (always lost has heat back out

to space)

Photosynthesis → feeding → decomposition

https://www.youtube.com/watch?v=lnAKICtJIA4

Bozeman energy flow in an ecosystem

Review

1.Where is some energy transferred to along the food chain?

2.How many trophic levels are in the diagram?

3.What is the name for the organisms in the first trophic level?

4.What is the name for the organisms on the second trophic level?

5.Where do all organisms ultimately get their energy from?

1. What are some abiotic

components in the

diagram that are

directly important to

the tree?

2. What is the primary

consumer getting

energy from?

3. How is the secondary

consumer dependent

on the producer?

Usable Energy Decreases with Each Link in a Food Chain or Web

Biomass: Dry weight of all organic matter of a given trophic level in a food chain or food web

Chemical energy is stored in biomass

Ecological Efficiency: % of usable energy transferred as biomass from one trophic level to the next

Typical is 10% efficient (90% of energy is lost)

Is diagramed as the Pyramid of Energy Flow

Ecological Pyramids

Many plants are

needed to feed fewer

snails which feed fewer

chickens which

feed fewer people

Most of the energy, mass, numbers are at the bottom of the food chain

10% Law only 10% of the energy is passed from one level to

the next

If a producer typically captures 5,000 units of energy from the sun, how

much usable energy will be available to a tertiary consumer in the

ecosystem?

• 5000 units x 0.1 = 500 units for primary consumers

• 500 units x 0.1 = 50 units for secondary consumers

• 50 units x 0.1 = 5 units for tertiary consumers

producer

secondary consumer

primary consumer

tertiary consumer

5000

500

50

5

1. In this food chain, we could hypothetically assume that for every kilogram of biomass in the osprey eagle, it would require __________ kg of shrimp to keep the food chain balanced. 2. The snapping turtle lives in a small pond, where its major prey is bass. In turn, the bass primarily eat minnows. This snapping turtle weighs 40 pounds. If the pond has 10 mature snapping turtles of this size, how many pounds of minnows are required to support them?

Solve the following energy pyramid problems… [Use the 10% law across each trophic level.]

1 kg

A snake weighs 2 lbs. Ecologists estimate

2000lbs. of grass plants exist. How many

snakes can the ecosystem support?

grass plants

mice

snakes

lbs.

10, 000,000 lbs.

100, 000, 000 lbs.

Fill in the biomass for the top trophic level in the ecological pyramid above.

At maturity a lion weighs 500 lbs. Ecologists estimate 100, 000, 000 lbs of grass plants exist in

the ecosystem. How many adult lions can the ecosystem support?

• How Fast Can Producers Produce Biomass? = Productivity

• Gross primary productivity (GPP): the rate at which

producers in an ecosystem convert solar energy into biomass

• Measured in Kcal/m2/year

• Net primary productivity (NPP): the rate at which

producers use photosynthesis to store energy minus the rate at

which they use some of this stored energy

R is the amount of energy used in respiration

APES

Monday November 2, 2015

Agenda:

Finish notes: biogeochemical cycles & watch video

Begin Study Guide

HW Learnerator Biogeochemical Cycles

Reminders:

Vocab. Quiz Wednesday Nov. 4th

Test Thursday Nov. 5th (Study 2014 FRQ #4)

• GPP vs. NPP:

• Some ecosystems have higher NPP than others:

Matter, in the form of nutrients, cycles within and among ecosystems and the biosphere, and human activities are altering these chemical cycles.

Biogeochemical cycles/ nutrient cycles

Hydrologic (water)

Carbon

Nitrogen

Phosphorus

Sulfur

• Hydrologic Cycle

• Only cycle in which nutrient does not undergo chemical change

Water into vapor Evaporation from

plant leaves Water vapor into

liquid droplets

Rain, sleet, snow

Movement of water

through soil & rock to

aquifers Surface movement

down slopes to the sea

• Alteration of the hydrologic cycle by humans:

• Withdrawal of large amounts of freshwater at rates faster

than nature can replace it

• Clearing of vegetation from land & cover it with buildings

& asphalt increases runoff, erosion

• Draining wetlands for farming and urban development

increases flooding

• Water Pollution

• Warmer climate change precipitation patterns

Cycling of Carbon • CO2 in

atmosphere

• converted to carbohydrates by producers during photosynthesis

• producers & consumers break down carbs during aerobic respiration, release CO2 back into atmosphere

• Decomposers release carbon stored in bodies

• CO2 is also dissolved in the oceans (major sink/reservoir)

• used in photosynthesis by marine producers

• involved in marine food webs

• Stored in limestone or sediments

Ecology: Cycling of Carbon • Over millions

of years, buried deposits of dead plant matter & bacteria are compressed between layers of sediment

• high pressure and heat convert them to fossil fuels

Alteration of the carbon cycle by humans:

Burn fossil fuels releases carbon dioxide into atmosphere

Electricity (burn coal)

Transportation (burn oil)

Clearing forests

Removes carbon-absorbing trees

Burning trees puts out CO2

CO2 is a greenhouse gas that

traps heat in our atmosphere

http://www.youtube.com/watch?v=8oblMClD2oU

https://www.youtube.com/watch?v=2D7hZpIYlCA

Crash Course Hydrologic & Carbon

Cycling of Nitrogen • Important

component of proteins & nucleic acids

• Atmosphere is major reservoir for nitrogen (N2)

• But N2 cannot be taken in by organisms

Steps:

1. Nitrogen fixation: nitrogen-fixing bacteria convert N2 to ammonia (NH3) then

dissolves to form ammonium (NH4

+)

Steps:

2. Nitrification: bacteria convert NH4

+ to nitrite (NO2

-) nitrate (NO3

-)

3. Assimilation: Nitrate is taken up by plants (cycles in food web)

Steps:

4. Ammonification

Decomposer bacteria convert nitrogenous wastes & dead organisms back into NH3 and NH4

+

5. Denitrification:

Bacteria convert NO3

- in soil back into N2 or N2O (nitrous oxide)

Cycling of Nitrogen

• Since 1950, human

activities have more

than doubled the

annual release of

nitrogen from the

land into the

environment

•Alteration of the nitrogen cycle by humans:

• Add nitric oxide (NO) to atmosphere when burning

fuel

• NO NO2 and HNO3 (nitric acid; part of acid rain)

• Add nitrous oxide (N2O) to atmosphere through

anaerobic bacteria feeding on fertilizers

• Remove nitrogen from topsoil when growing &

irrigating crops

•Alteration of the nitrogen cycle by humans: • Add excess nitrates to aquatic systems through

agricultural runoff of fertilizers & manure or sewage

• Causes Eutrophication – growth of cyanobacteria & phytoplankton = algal blooms

• Especially in marine ecosystems like estuaries

• Results in oxygen depletion & biodiversity loss

• Creates “Dead Zones”; examples:

• Gulf of Mexico

• Chesapeake Bay Estuary

• Can create “Red Tide” – toxic algal bloom

• Can poison fish, mammals, birds

Cycling of Phosphorus • Does not

include the

atmosphere

• Reservoir:

salts containing

phosphate (PO43-

) in rock

formations &

bottom of oceans

https://www.youtube.com/watch?v=6LAT1gLMPu4

• As water erodes rock, phosphate ions enter soil

• Phosphate taken up by plants & enter food web

• Important for nucleic acids and energy transfer molecules (ATP)

• Most soils

contain little

phosphate, so

limits plant

growth

(limiting

factor!)

• That’s why

fertilizers have

phosphate

•Alteration of the phosphorus cycle by

humans:

• Removing phosphate salts from mining

• Phosphate-rich runoff enters aquatic systems (esp.

freshwater) & causes algal blooms (eutrophication)

https://www.youtube.com/watch?v=leHy-

Y_8nRs

Crash Course N & P

Cycling of Sulfur • Much of world’s

sulfur is in rocks

& minerals &

sulfate (SO42-)

salts in ocean

sediments

• S enters the

atmosphere from:

• Volcanoes & break

down of organic

matter by anaerobic

decomposers

hydrogen sulfide

(H2S)

• Sulfate (SO42-)

particles come from

dust storms & forest

fires

In atmosphere, sulfur dioxide (SO2)

is converted to sulfur trioxide gas (SO3) & sulfuric acid (H2SO4)

-Sulfate cycles through food webs

• Alteration of the sulfur cycle by

humans:

• Factory emissions: sulfur in coal is

released into atmosphere when we

burn it

• Leads to acidic precipitation

(sulfuric acid)

• Refining petroleum

• Smelting metallic ores (copper, lead, zinc)

• Smelt: To melt or fuse (ores) in order to separate the

metallic constituents.

https://www.youtube.com/watch?v=Bn41lXKyVWQ

Bozeman biogeochemical cycles

Biomes & Aquatic Life Zones

Large regions of similar ecosystems:

Terrestrial areas are called biomes: large regions characterized by a distinct climate and specific species adapted to it

Forests (conifer, deciduous, rain forest)

Deserts

Grasslands

Aquatic areas are called aquatic life zones: Freshwater (lakes, ponds, rivers, streams, wetlands)

Marine (coral reefs, coastal regions, deep ocean)

Ecology: Biomes & Aquatic Life Zones

Biozone Assignments: Lab

Review for Unit 5 • Primary Succession worksheet

• Nitrogen Cycle page (p. 75-76)

• Phosphorus Cycle (p.80)

• Sulfur Cycle (p. 81)

• Once done – work on Study Guide

•Warm-Up Video: Should We All Be Eating Insects? https://www.youtube.com/watch?v=iM8s1ch5TRw&list=UUC552Sd-

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