ECOLOGY AND ECOSYSTEMS

ECOLOGY

IS THE STUDY OF THE INTERACTIONS BETWEEN ORGANISMS AND THEIR

ENVIRONMENTS

ECOSYSTEM• A LIMITED AREA IN WHICH

LIVING AND NONLIVING THINGS INTERACT

• IT IS SHAPED BY:1. ABIOTIC FACTORS - THE

NONLIVING FACTORS / PHYSICAL ENVIRONMENT

2. BIOTIC FACTORS- LIVING ORGANISMS

ACTIVITY #1

PLACE THE EAGLES IN THE

PROPER CATEGORIES,

DEPENDING ON WHETHER THEY

ARE DESCRIBING AN ABIOTIC

FACTOR OR A BIOTIC FACTOR.

Ecosystem Dynamics

TWO KEY PROCESSES:

1. ENERGY FLOW

2. CHEMICAL CYCLING

ENERGY FLOW

Two types of energy sources:

1. Light Energy- the main energy source for life on Earth; used by autotrophs to carry out photosynthesis.

2. Inorganic Chemical Compounds-

are used by autotrophs that can produce food in the absence of light. The process is called “chemosynthesis.”

• PRODUCERS – autotrophs MANUFACTURE THEIR OWN FOOD – via PHOTOSYNTHESIS or CHEMOSYNTHESIS.

• CONSUMERS – heterotrophs rely on other organisms for their energy and food supply.

TYPES OF CONSUMERS - Heterotrophs

• HERBIVORES- eat only plants• CARNIVORES – eat animals • OMNIVORES – eat both plants and

animals• DETRITIVORES – feed on animal

remains or other dead matter ( crabs, earthworms, ants)

• DECOMPOSERS- break down organic matter ( bacteria, fungi)

What’s for dinner?

• FOOD CHAINS- a series of steps in which organisms transfer energy by eating and being eaten.

• FOOD WEBS- link all the food chains in the ecosystem together.

• TROPHIC LEVEL- each step in a food chain. Producers – first level, consumers- second, third or higher.

Ecological Pyramids

Ecological pyramid is a diagram that shows the amounts of energy or matter contained within each trophic level.

3 Types:

ENERGY PYRAMID

BIOMASS PYRAMID

PYRAMID of NUMBERS

Energy Pyramid

Shows the relative amount of energy available at each trophic level. Organisms use about 10 percent of this energy for life processes. The rest is lost as heat.

Biomass Pyramid

Represents the amount ofliving organic matter at each trophic level. Typically, thegreatest biomass is at the base of the pyramid.

Pyramid of Numbers

Shows the relative number of Individual organisms at eachtrophic level.

How much energy is available to first-, second-, and third-level consumers, if there are 50,000 kcal available at the producers’ trophic level?

A 250, 25, and 1 B 3000, 250, and 25C 5000, 500, and 50D 1, 25, and 250

In the food chain, what percentage of the energy stored in the krill probably would be transferred to the cod?

A. More than 90 percentB. About 75 percentC. About 50 percentD. Less than 15 percent

What is true about the pyramid of numbers?

i 1st level consumers compose the greatest number of individuals.

ii There are more 3rd level consumers than 2nd level consumers.

iii There are more producers than 1st level consumers.

A. i only D. ii and iii only

B. ii only E. i, ii, and iii

C. i and ii only

BIOMASS PYRAMID:

PYRAMID OF NUMBERS:

Producers

1st Level Consumers

2nd Level Consumers

3rd Level Consumers

What can you conclude based on the two pyramids?i The producers are probably small, like single-celled algae in a body of water.ii The producers are probably large, like trees in a forest.iii No reasonable conclusion can be drawn from the information given.

A. i only D. ii and iii onlyB. ii only E. i, ii, and iii C. i and ii only

BIOMASS PYRAMID:

PYRAMID OF NUMBERS:

Producers

1st Level Consumers

2nd Level Consumers

3rd Level Consumers

CYCLES OF MATTER

Only 4 elements –

oxygen

carbon

hydrogen

nitrogen

-make up over 95% of the body in most organisms.

Cycles of Matter

Unlike the one-way flow of energy, matter is recycled within and between ecosystems.

The process of chemical recycling in an ecosystem, involving both biotic and abiotic factors- is called Biogeochemical Cycle;

BioGeoChemical Cycle

Geologic Processes

Abiotic reservoir

Nutrients avail. to producers

Producers

Consumers

Detritivores

Condensation

Seepage

Runoff

Precipitation

TranspirationEvaporation

RootUptake

The Water Cycle

The Water Cycle

There are 3 major processes driven by solar energy: Precipitation, Evaporation, and Transpiration - that continuously move water between the land, oceans, and atmosphere.

Over the oceans, evaporation > precipitation; Water vapor in clouds gets carried by winds

across the land. On land, precipitation > evaporation and

transpiration. The excess precipitation forms lakes, rivers, and groundwater- that flow back to the sea, completing the water cycle.

The Carbon CycleCO2 in

Atmosphere

CO2 in Ocean

The Carbon Cycle

Carbon- major ingredient of all organic molecules. Its abiotic reservoir is atmosphere, oceans, rocks, soil; biotic- organisms.

Photosynthesis, respiration, and decomposition take up and release carbon and oxygen.

Erosion and volcanic activity release carbon dioxide

Decomposition- leads to fossil fuels, carbon underground.

Human activities- mining, burning fuels, etc. release carbon dioxide.

The Nitrogen Cycle N2 in Atmosphere

NH3

NO3-

and NO2-

The Nitrogen Cycle

The main reservoir- atmosphere. Ingredient of amino acids; Cycles through the soil and organisms.

Although atmosphere contains 79% nitrogen gas, only certain types of bacteria can use this form directly. The bacteria lives in the soil, plant roots and binds nitrogen to hydrogen to form ammonia

(process called “nitrogen fixation”); Other bacteria performs “nitrification”- convert ammonia into nitrates and nitrites.

Denitrification- nitrates converted into nitrogen gas.

Phosphorus Cycle

Part of DNA and RNA; does not enter atmosphere.

Main abiotic reservoir- rock, which upon weathering releases phosphorus.

Some phosphate cycles between organisms and the soil on land.

Levels of Organization

Levels of Organization

BIOSPHERE- part of Earth in which life exists including land ( lithosphere), water (hydrosphere), and air ( atmosphere.)

Earth’s Surface

8km ~ 5miles

11km ~ 6.8miles

Levels of Organization

BIOME- a group of ecosystems that have the same climate and dominant communities ( plants & animals.)

Examples: Tropical Rain Forest

Desert

Temperate Grassland

Tundra

10 MAJOR BIOMES

Ten Major BiomesBiome Precipitatio

nTemperature Soil Diversity Trees Grasses

Tropical Rain Forest

high hot poor high dense sparse

Tropical Dry Forest

variable mild rich moderate medium medium

Tropical Savanna

variable mild clay moderate sparse dense

Desert low variable poor moderate sparse sparse

Temperate Grassland

moderate summer hot rich moderate absent dense

Temperate woodland and Shrubland

summer low, winter moderate

summer hot poor low medium medium

Temperate Forest

moderate summer moderate, winter cold

rich high dense sparse

Northwestern Coniferous Forest

high summer mild, winter cold

rocky, acidic

low dense sparse

Boreal Forest moderate summer mild, winter cool

poor, acidic moderate dense sparse

Tundra low summer mild, winter cold

poor low absent medium

The Role of Climate

Most direct sunlight

Sunlight

Sunlight

Sunlight

Sunlight

Levels of Organization

ECOSYSTEM- all organisms in a particular area, along with the abiotic factors with which they interact.

Examples: Lakes, Forests, Marshes, etc.

Two general categories of ecosystems:- Terrestrial - Aquatic

Levels of Organization

COMMUNITY – all of the organisms living in a specific place.

Levels of Organization

POPULATION – groups of individuals that belong to the same species and live in the same area/ecosystem.

Can a group of rabbits and a group of mice make up the same population in an ecosystem?

Levels of Organization

INDIVIDUAL SPECIES – a group of organisms that are similar to one another and can breed and produce fertile offspring;

Organism- the smallest living unit of the biosphere.

BIODIVERSITY- the number and variety of species living within an ecosystem.

CARRYING CAPACITY– the ability of the ecosystem to support the organisms in its ecosystem.

Community Interactions

When organisms live together, they interact.

Interactions such as COMPETITION, PREDATION, and SYMBIOSIS help shape the ecosystem in which they live.

• Competition- organisms compete for the same limited resource ( water, nutrients, light, food, or space.)

“ Competitive exclusion principle”- no two species can occupy the same niche in the same habitat at the same time.

Predation- one organism captures and feeds on another.

• Symbiosis- “living together”:

Mutualism – both organisms benefit

Commensalism- one organism benefits and the other is neither harmed nor helped

Parasitism- one organism, the parasite, benefits; and the other, the host, is harmed

Test your knowledge:

1. The anemone is found attached to the shell in which the hermit crab lives. When crab searches for food, the anemone is brought into contact with a greater supply of food. The crab doesn’t mind his host; anemone's stinging cells protects him too.

2. Tapeworms have no gut, so they rely on their host to provide them with already digested food. The host later suffers harm.

3. Oxpeckers run over the backs of hippopotami. These birds rid their partners of injurious and annoying pests and in doing so obtain a ready supply of food.

4. Spiders build their webs on trees.5. Phoretic mite attaches the fly for transportation only.