Biology 20Equilibrium in the Biosphere

Ecology explain the one-way flow of energy through

the biosphere and how stored biological energy in the biosphere is eventually “lost” as thermal energy

explain how biological energy in the biosphere can be perceived as a balance between both photosynthetic and chemosynthetic, and cellular respiratory activities

Ecology Study of the interactions between organisms and

their physical environment and with each other. includes aspects of both the living (biotic) and

non-living (abiotic) components of the physical environment.

Biosphere Biosphere

the part of the earth that is inhabited by organisms.3 parts:1 Lithosphere

Land1 Hydrosphere

water1 Atmosphere

The gasses that surround the Earth.

Living vs. Non-living There are two factors which make up

the biosphere. Biotic Factors

Living components of the biosphere plants and animals…

Abiotic Factors Non-living components

of the biosphere minerals, water, weather...

Interactions Within the Biosphere

Abiotic vs Biotic When a non-living factor affects a living factor.

i.e. The weather affecting a living organism Biotic vs. Biotic

When a living factor affects another living factor. i.e. Two organisms fighting for the same food.

Biotic vs. Abiotic Abiotic vs. Abiotic

Levels of Organization

Levels of organizationCell Tissue Organ

System Organism

Population

CommunityEcosystem

BiosphereBiome

Levels of Organization

Hierarchical Levels within the Biosphere

Biosphere

Ecosystem

Community

Population

Organism

World

Lake or River

Lots of different species of

organisms

Lots of same species of fish

Fish

Important Definitions Population: group of individuals of the

same: species, place & time Community: populations of all species

in an area Ecosystem: community and its biotic

and abiotic factors interactions

Biome: large scale ecosystems Can be found around the world tundra,

grassland

Food Chain a linear illustration that represents the step

sequence of who eats whom in the biosphere.

used to show: energy transfers cycling of matter through the biosphere

Two types: Grazer: plant, herbivore, carnivore Detritus: organic waste

Waste – scavengers – decomposers

Assignment 1.1 Use your text book and define the

following Terms Biodiversity Producer ConsumerRead pages 8-10 (new text only)Do Questions 1-7 section 1.1 page 10

Equilibrium Unbalanced

Autotrophs “self feeders” Require energy from sun –

photosynthesis Convert energy from sun into a form of

energy that other living things can use Provides O2 – required by all living

things Provide basic molecules for life

Carbohydrates, proteins, fats, and nucleic acids

PRODUCERS!

Heterotrophs Require a source of chemical energy and

basic organic molecules NO photosynthesis Feed on plants OR other heterotrophs CONSUMERS!

A primary consumer eats a producer A secondary consumer eats a primary

consumer A tertiary consumer eats a secondary

consumer…

General Terms

Herbivore An organism that only eats plants.

Rabbit, squirrel

Carnivore An organism that only eats animals.

Wolf, Lion, Tyrannosaurus Rex

Omnivore An organism that eats both plants and

animals. Bear, Human

More General Terms Scavenger

An organism that feeds on dead organisms or the wastes of organisms. Vulture, Seagull,

Decomposer An organism that breaks down organic wastes

and the remains of dead organisms into simpler compounds such as: carbon dioxide ammonia Water

Species At-Risk

Species At-Risk

Species At-Risk Indicator Species – A species sensitive

to small changes in environmental conditions

Describe why frogs and other amphibians are important indicator species:

Frogs live in two different ecosystemsWater as a tadpoleIn forest and grassland as adultsAny hazards in either ecosystem will have an

effect on the frogs.Also frogs occupy two different food

chains.

Why Are Frogs Disappearing? The worldwide disappearance of frogs

is puzzling scientists around the globe.

- Loss of Habitat• Frogs need wetlands, ponds, or lakes

with clean water to breed and lay their eggs.

• They need a place where they can catch insects such as forest and fields.

- Air and Water Quality Frogs can breath through their skin, pollutants

can also pass through their skin. Acid of water also has an ability to reproduce.

- Climate Change Climate change can cause important changes in

local ecosystems. If the climate becomes drier frogs populations will

decline.

4. Ultraviolet Radiation The thin skin of the frog is susceptible to

ultraviolet radiation. The amount to UV radiation reaching

Earth's surface is increasing because of damage to the protective ozone layer surrounding Earth.

Biology 20EcologyEnergy and Matter Exchange

27

General Terms Ecosystem

A community of organisms interacting with each other and with their nonliving surroundings.

Autotrophs –Producers Heterotrophs - Consumers

Input energy

Biogeochemical

Cycles

Energy Lost

Ecosystems are OPEN SYSTEMS. Energy and matter can flow in and out of system

Ecosystem Models

Explain the structure of ecosystem trophic levels, using models such as food chains and food webs

Food chainsFood Chain step sequence of who eats whom in the

biosphere. used to show:

energy transfers

Characteristics: Energy is transferred from organism to

organism Each time energy is transferred about 90% is

lost as heat or used for life processes

Food Chain

Note that: the arrow points at

the eater the arrows separate

trophic (eating) levels

Trophic Levels Trophic level: how far an organism is

from the original energy source Plants – first trophic level

Original energy is from the sun When an organism is ingested by

another, energy is transferred Plant – mouse – owl Producer – primary consumer –

secondary consumer (top carnivore) T1 – T2 – T3

Food Webs What would happen if we relied on deer for our

food? In reality, a consumer relies on more than one

food source If one source is scarce, consumer can eat more of

something else Food web:

a series of interlocking food chains more accurately represents energy pathways

who eats whom… really

Food Web ABCD represent

different trophic levels.

Level D represents the decomposers

Laws of ThermodynamicsBiosphere requires a constant flow of energy

Energy flows one way through the biosphere following basic scientific principles called the laws of thermodynamics

Laws of Thermodynamics

Energy can be changed in form, but not created or destroyed.

(Law of conservation of energy)

Energy input = Energy Output

First Law

Second Law

Any energy change results in loss of energy as heat

Energy input desired energy + waste energy

Energy Flow About 10% of the energy is transferred

from one trophic level to the next.

During any change, some of the energy is lost as waste energy or heat.

Applied to an ecosystem, as energy flows through the community there is energy loss at each trophic level.

Much of this loss is in the form of heat which is lost when food molecules are broken down in the cells.

There would be less energy loss in the community if only herbivores fed on the producers

Energy Flow in the Ecosystem

•explain quantitatively, energy exchange in ecosystems, using models such as pyramids of energy , biomass, and numbers •explain the interrelationship of energy, matter and ecosystem productivity (biomass production)

Ecological Pyramids Ecological pyramids illustrate the energy loss

through the trophic levels Solar radiation transformed in plants

Plants create chemical energy Plant eaten by consumer Energy lost at each transformation

Higher trophic level = less energy available Number of trophic levels limited b/c of loss of

energy

Ecological Pyramids In ecological pyramids,

Base -the producer populations Next Level - the primary consumers Higher levels and above -the secondary,

tertiary etc.

Ecological Pyramids Three types:

Numbers: total number of organisms in each trophic levels

Biomass: mass of dry tissue of organisms at each trophic level shows how mass decreases as you move up

the food chain Energy: based on energy produced at

each trophic level

Ecological Pyramids

Pyramid of Numbers

Pyramid of Biomass

Human Interference in the Ecosystem

FireHunting and fishingMonoculturePesticide usage and biological amplification (magnification)

Fire Before the Europeans settlement,

wildfires swept across the land. Fire destroys vegetation, returning

nutrients to the soil Fire usually only destroys vegetation

above ground. Allowing new growth. Fire prevents the over growth of aspen

parkland into the grassland ecosystem

Fire European settlement Impact upon

grasslands. Fire control (More Aspen Parkland) Introduction of many new species of

plants(Mustard, pepperfrass, Russian thistle, pigweed, and stinkweed)

Hunting and fishing New technology has improved ways of

finding animals. Which has resulted in: Over hunting and fishing Reducing the number of animals.

Monocultures Monoculture:

growing a single species of plant, excluding others

Huge diversity of species on earth 6 - 15 million

Ecological change = species extinction Humans = biggest change maker

Monoculture Effects Impact? Humans rely on a small variety of species Other species being decimated

At what cost? Loss of diversity Loss of possible cures

Rainforests: soil not suited to human needs loses productivity in a few years

Pesticides

Pesticides used to kill pests mosquitoes - malaria pesticides in food chain accumulate causes loss of diversity.

Example DDT: dichloro diphenyl trichloroethane

developed as a biological weapon in WWII 1950’s - used as a pesticide for insects

DDT also affects human pops found in breast milk came from sprayed crops

animals that ate crops Banned in Canada and US in 1970’s Not banned in other areas - Mexico,

Central America Continues to be produced as a cheap

pesticide in poorer nations

Biological amplification Pesticides accumulate at the top level of

the pyramid toxins accumulate in fatty tissue

not released in wastes accumulates each time you move up higher trophic level - higher

concentration

Biogeochemical cycles explain and summarize the cycling of

carbon, oxygen, nitrogen, and phosphorus and relate it to the reuse of all matter in the biosphere

explain water’s role in the matter cycles, using its chemical and physical properties

explain how the equilibrium between gas exchanges in photosynthesis and cellular respiration influences atmospheric conditions