Energy and chemicals flow within ecosystems

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Energy and chemicals flow within ecosystems

12 Energy flows from producers to consumers.

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First Stop: Primary Producers4

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Primary Producers

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Second Stop: Primary Consumers – the Herbivores

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Herbivores

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Third Stop: Secondary Consumers – the Carnivores

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Carnivores

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Fourth Stop: Tertiary Consumers – the “Top” Carnivores

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Food Chain

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Food Web

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Food Web

Food Chains & Food Webs14

Food Chains & Food Webs15

GRASS

GRASSHOPPER

TOAD

SNAKE

HAWK

BACTERIA

IN GENERAL,

AUTOTROPHS (PRODUCERS)

HERBIVORES(PRIMARY

CONSUMERS)

CARNIVORES(2, 3, ETC.)

DECOMPOSERS

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Chain Reaction Game

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Decomposers

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Energy Flows through a Food WebLosses at every “step” in a food chain

Inefficiency of energy transfers

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Summary 12.1Energy from the sun passes through an

ecosystem in several steps. First, it is converted to chemical energy in

photosynthesis. Herbivores then consume the primary

producers, the herbivores are consumed by

carnivores, and the carnivores, may be consumed by top

carnivores.

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Summary 12.1Detritivores and decomposers extract

energy from organic waste and the remains of organisms that have died.

At each step in a food chain, some usable energy is lost as heat.

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Energy and chemicals flow within ecosystems

12.2 Energy pyramids reveal the inefficiency of food chains.

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Biomass

only about 10% of the plants in an ecosystem is converted into biomass

Food Energy Pyramid◦ trophic levels:

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Summary 12.2Energy from the sun passes through an

ecosystem in several steps known as trophic levels.

Biomass of primary producers in an ecosystem is far greater than the biomass of herbivores.

Biomass transferred at each step along the food chain is 10% of the biomass of the organisms being consumed, due to energy lost in cellular respiration.

Food chains rarely exceed four levels.

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Energy and chemicals flow within ecosystems

12.3 Essential chemicals cycle through ecosystems.

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Chemical Reservoirs

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The Most Important Chemical Cycles

1) Carbon

2) Nitrogen

3) Phosphorus

4) Sulfur

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Carbon Cycle Game

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Fossil Fuels

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Global CO2 levels exhibit a sharp rise and fall within each year

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Fertilizers

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Phosphorus

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Sulfur Cycle

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Sulfur Cycle

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Summary 12.3Chemicals essential to life, cycle through

ecosystems. Captured from the atmosphere, soil, or water

by growing organisms; passed from one trophic level to the next as organisms eat other organisms;

Returned to the environment through respiration, decomposition, and erosion.

human activities increase the amounts of the chemicals utilized or released to the environment.

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Species interactions influence the structure of

communities.12.4 Interacting species evolve together.

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Coevolution◦predator/prey

◦parasite/host

◦competitive species

◦mutualistic species

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Penicillin was first isolated from a fungus growing on a plate of bacteria.

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Summary 12.4In producing organisms better adapted to

their environment, natural selection does not distinguish between living and non-living (biotic and abiotic) things as selective forces.

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Species interactions

influence the structure of

communities.12.5 Each species’ role in a community is

defined by its niche.

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More than just a place for living, a niche is a complete way of living

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A niche is a complete way of living

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Summary 12.5A population of organisms in a community

fills a unique niche, defined by how they use the resources in their environment.

Organisms do not always completely fill their niche; competition with species that have overlapping niches can reduce their range.

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Species interactions influence the structure of

communities.12.6 Competition can be hard to see, but it

still influences community structure.

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Competition

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Why is competition hard to see?

E.g. birds singing in the morning.

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Competitive exclusion principle

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Summary 12.6Populations with completely overlapping

niches cannot coexist forever.

Competition for resources occurs until one or both species evolve in ways that reduce the competition, through character displacement, or until one becomes extinct in that location.

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Species interactions influence the structure of

communities.12.6 Predation produces adaptation in both

predators and their prey.

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Predation

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Non-Native Species

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Prey Adaptations

physical◦ Mechanical

◦ Chemical

◦ warning coloration

◦ camouflage mechanisms

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Prey Adaptations

behavioral Hiding Escaping

alarm calling

fighting back

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1) Mechanical Defenses

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3) Warning Coloration

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4) Camouflage

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Predator adaptations

• toxic-avoidance methods

• sensory perception

• faster running ability

• mimicry

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Why don’t predators drive the prey to extinction?

• predator adaptations

• escape ability

• cost of losing is much higher for prey

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The gazelle can change direction very quickly while being chased by a cheetah (fastest land animal). The gazelle uses which method of defense listed below?

1. Mechanical defense2. Camouflage3. Behavioral4. Warning Coloration5. Chemical defense

Symbiotic Relationships Symbiosis: close relationship between

organisms of two different species At least one participant gains some

sort of benefit (usually nutritional) Types of symbiosis:

◦ Parasitism◦ Mutualism◦ Commensalism

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Parasitism Parasite derives nutrition from the host This harms the host but a true parasite

does not usually kill its host (directly)

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Ectoparasites

Remain outside the hostTicks, fleas, leeches

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Endoparasites

Live inside the host’s bodyTapeworms, malarial parasites

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Parasite Transmission Many parasites live on or in a single

organism Some will alternate between 2 or more host

species◦ Vertical transmission – from mother offspring◦ Horizontal transmission – between members of a

population Direct contact (head lice) Vectors (mosquitos)

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Mutualism Both species benefit Food or shelter Examples:

◦ Plants and microbes (rhizobium in root nodules)

◦ Plants and fungi (orchids and mycorrhizae) ◦ Protists and fungi (lichen)◦ Plants and insects (pollination)◦ Animals and bacteria (ruminants)◦ Animals and other animals (crocodiles and

plover birds)81

Rhizobium

Rhizobium in root nodules of certain plants convert nitrogen in soil to usable form.

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Lichen

Most of the lichen is composed of fungal filaments, but living among the filaments are algal cells, usually from a green alga or a cyanobacterium.The lichen fungus provides its partner(s) a benefit (protection) and gains nutrients in return. 83

Ruminants

Ruminants are characterized by their four-chambered stomach and "cud-chewing" behavior. Cud is a food bolus that is regurgitated, rechewed, and reswallowed. The rumen is a large fermentation vat containing billions of microorganisms, including bacteria and protozoa, which allow ruminants to digest fibrous feeds such as grass and hay that other animals cannot efficiently utilize.

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Crocodiles & Plover Birds

The bird gets into the crocodile's mouth and picks out the tiny bits of food stuck in his teeth, then eats it (the tiny bits). This cleans the crocodile's teeth and keeps his mouth fresh and free from infections.

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Commensalism

Neither species is totally dependent on the other

One benefits – no effect on the other Feeding or protection Cattle egrets Porcelain anemone crabs and anemon

es

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Commensalism

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THANK YOU TO…

http://www.blueplanetbiomes.org http://www.marietta.edu/~biol/biomes/biome_main.htm http://www.ucmp.berkeley.edu/exhibits/biomes/ http://www.tburg.k12.ny.us/mcdonald/foodch1.htm http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/F

/FoodChains.html http://ic.galegroup.com/ic/scic/ReferenceDetailsPage/

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