Three hundred trout are needed to support one man for a year. 

The trout, in turn, must consume 90,000 frogs, that must consume 27 million 

grasshoppers that live off of 1,000 tons of grass. 

-- G. Tyler Miller, Jr., American Chemist (1971)

2.1.4 Pyramids in Ecosystems

2.1.5 How Pyramid Structure Affects Ecosystems

Pyramids

Graphical models of the quantitative differences between trophic levels of a single ecosystem

Usually Pyramids become narrower toward the top

http://www.geog.ouc.bc.ca/physgeog/contents/9o.html

Pyramids of Numbers

Number of individuals at each trophic level.

If the size of an organism is small, more can be present.

I.e.: ten mice in place of one rabbit.

http://www.biology.com/kimball/kimball.html?maincontent=F/FoodChains.html

Pyramids of Numbers - Variations A shows a typical pyramid of numbers

for carnivores; B shows the effect of a single large

producer such as a tree; C shows a typical parasite food chain

Blue birds

Pyramids of Biomass

Represents the standing stock of each trophic level

Measured in g of biomass per square meter

g/m2

http://www.biology.com/kimball/kimball.html?maincontent=F/FoodChains.html

Pyramids of Biomass more information -

consider total mass of organisms

almost always pyramid shaped, if a trophic level

gains all mass from the level below,

cannot have more mass than that lower level ( cannot weigh more than you eat).

The "missing" mass, that not eaten, becomes detritus and is decomposed. http://cr.middlebury.edu/es/altenergylife/biomass%20logo.gif

Inverted Pyramids

Occurs in BOTH pyramids of numbers and biomass

Occurs more often with numbers

Can also result from seasonal fluctuations, weather and natural disasters (biomass).

Pyramids of Energy

Show flow of energy through a trophic level (or the rate at which stock is generated)

90% of energy is lost at each transfer.

Conversion efficiency: ratio of net production at one level to to that of the next.

http://www.biology.com/kimball/kimball.html?maincontent=F/FoodChains.html

Pyramids of Energy: Loss?

Only 10% energy incorporated into biomass, the remaining 90% is lost as:1) feces2) used in respiration and lost as heat3) lost in urine

http://www.buildingenergyireland.ie/classified/beriheatloss1_lg.jpg

How does the Pyramid Structure Affect Ecosystems?

Typical Pyramid higher trophic

levels have less total biomass than those below

less energy is available

lower level sets the limit at the next level

Pyramid of energy - takes into account the turnover rate of the organisms, and can never be inverted.

http://i.pbase.com/o5/05/621605/1/67425663.LXLjH2og.IMG_1071.JPG

Ecosystem Function & Pyramids "bottom-up"

control - nutrient supply to the primary producers

"top-down" controls - predation and grazing by higher trophic levels

Pyramid Structure & Function?What type of controls do these exert

on food chains? Concentration of non-biodegradable

toxins? Limited length of food chains? Vulnerability of Top Carnivoes?

www.facstaff.bucknell.edu/ abrahmsn/bi356/

Species

A group of organisms that interbreed and produce fertile offspring.

Physical, chemical, or behavioral differences limit breeding between species

www.ramsar.org/ photo_species1.htm

Population

A group of organisms of the same species

living in the same area at the same time, and

which are capable of interbreeding.

sunsite.tus.ac.jp/multimed/ pics/animals/wolves-07.gif

Community

A group of populations living and interacting with each other in a common habitat.

www.aipress.com/pictureawards/ 28976-10.Catapillar.jpg www.bham-bot-gdns.demon.co.uk/ other.html

www.archbold-station.org/.../ unit4/unit4intro.html

Niche

A species' share of a habitat and the resources in it. ecological niche - depends on

where it lives AND what it does.

fundamental niche - the part of the habitat in which a species can live in the absence of competitors and predators

realized niche - the part it actually occupies is its.)

Habitat

The environment in which a species normally lives.

Example- woods, desert, swamp

www.ebibleteacher.com/ images/swamp.jpg

Ecosystem

A community of interdependent organisms and the physical environment they inhabit

http://blackhawkhomesteadnurscom.nxg.superpageshosting.com/ecosystem.jpg

Biome

A collection of ecosystems sharing similar climatic conditions, eg tundra, tropical rainforest, desert.

http://www.donnalatham.com/images/Biomes_Cvr.jpg

References

http://www.angelfire.com/sk/monkeypuzzle/index.html

http://martin.parasitology.mcgill.ca/jimspage/biol/intro.htm

http://www.schools.lth5.k12.il.us/bths-e/cowbird.html

Environmental Science, Toward a Sustainable Future Eight Edition by Richard T. Wright and Bernard J. Nebel

http://www.stanfordalumni.org/birdsite/text/essays/Disease_and_Parasitism.html

The May Fly

Species - Giant May Fly - (Hexagenia limbata)

Population – greater in forested streams as opposed to ag or residential http://www.insectidentification.org/imgs/

insects/giant-mayfly.jpg

The Mayfly Community

in nymph stage, shares stream bed with other benthic macroinvertebrate

As adults swarm with stonefly,caddisfly, for example

http://insects.tamu.edu/extension/youth/bug/bug003.html

Mayfly Niche

dwell in and around water sources laying their eggs in the water Eating habits

(larve/nymphs) are generally herbivores--eating plant materials like fine detritus and algae

Adults do not eat (only mate and die, live 90 min to 3 days)

Important important food for many species of fish

Mayfly - Habitat

Habitat – stream bed/above stream

http://images.google.com/imgres?imgurl=http://www.wiflyfisher.com/images/photos/sulphur-habitat.jpg&imgrefurl=http://www.wiflyfisher.com/sulphur-mayfly-

hatch.asp&usg=__rUH2BM4xyU_2R7PVIFzgVXLygyA=&h=384&w=512&sz=105&hl=en&start=3&um=1&itbs=1&tbnid=mxUc0Ps4wiK_3M:&tbnh=98&tbnw=131&prev=/images%3Fq%3Dmayfly%2Bhabitat%26gbv%3D2%26hl%3Den%26sa%3DN%26um

%3D1

Mayfly - Ecosystem

Freshwater Aquatic Ecosystem

http://www.nwfund.org/images/10sc060.jpg

Mayfly Biome

Freshwater Streams found in a Temperate Deciduous Forest

http://earthobservatory.nasa.gov/Experiments/Biome/Images/pictemperate.jpg

A community is composed of1. biotic and abiotic factors.2. several habitats.3. several abiotic factors.4. several populations.

Species X and Y are both at trophic level 2 and species Z is at trophic level 3. Which are the most likely relationships between the species? Relationship between:

Species X & Y Species Z & Xa. Mutualism Herbivoryb. Mutualism Competitionc. Competition Predationd. Parasitism Predation

Mutualism is an interaction between two species in which

1. one benefits and the other is harmed

2. both benefit3. one benefits and the other is

harmed.4. both are harmed

Which of the following is most likely to be a parasite?

1. A fungus in the living tissues of a tree2. A fungus cultivated as a source of food

by ants in their nest3. A fungus growing on the decaying

branch of a dead tree4. A caterpillar consuming the tissue of a

living fungus