What is an Ecosystem• An ecosystem is made up of

biotic as well as abiotic factors.• The interactions of living organisms

with their physical environment builds up the ecosystem and is designated as the bioshphere or ecosphere

• Examples: a pond, a forest, an estuary, a grassland

Biotic Factors

Abiotic Factors

Abiotic factors affect living organisms in an ecosystemFires destroy forests, but can sometimes help a forest community by allowing

new organisms to thrive

Early or unexpected frost can kill plants and

an entire food chain.

Wind can affect the way an organism grows

Biotic factors affect the abiotic factors in an ecosystem

Lichens on rocks help break them down into soil. Lichens are made

up of algae and fungi.

Dead organisms and animal waste contribute to soil nutrients (with the help of decomposers,

of course)

ECOLOGY

• ECOLOGY IS AN SCIENTIFIC STUDY OF THE INTERACTION THAT DETERMINE THE DISTRIBUTION AND ABUNDANCE OF ORGANISMS

Ecology—the scientific study of interactions between different organisms and between organisms and their environment or surroundings

TYPE OF ECO SYSTEM

• NATURAL ECO SYSTEM

• ARTIFICIAL ECOSYSTEM

NATURAL1.Terrestrial ecosystems (grasslands, forests, desert ecosystems)

2.Aquatic ecosystem

a.Lentic (Stagnant water) like lake, ponds etc.

b.Lotic (Flowing water) like river, ocean, sea, etc.ARTIFICIAL1.A crop land, garden, aquarium, park, kitchen garden.

STRUCTURE AND FUNCTION OF STRUCTURE AND FUNCTION OF ECOSYSTEMECOSYSTEM

• Two important aspects of the ecosystem are Architectural Two important aspects of the ecosystem are Architectural (Structural)(Structural)

• 1.The composition of biological community including 1.The composition of biological community including species numbers, biomass, life history and distribution in species numbers, biomass, life history and distribution in spacespace

• 2.The quantity and distribution of nonliving materials like 2.The quantity and distribution of nonliving materials like nutrients, water.nutrients, water.

• 3.The condition of existence such as temperature, light 3.The condition of existence such as temperature, light etc.etc.

STRUCTURE AND FUNCTION OF STRUCTURE AND FUNCTION OF ECOSYSTEMECOSYSTEM

• Two important aspects of the ecosystem are working Two important aspects of the ecosystem are working processprocess

• 1.The production and respiration rates of the community1.The production and respiration rates of the community

• 2.The rate of material (nutrient) cycles2.The rate of material (nutrient) cycles

• 3.Biological regulation including both regulations of 3.Biological regulation including both regulations of organisms by environment (Photoperiodism) and organisms by environment (Photoperiodism) and regulation of environment by the organisms (Nitrogen regulation of environment by the organisms (Nitrogen fixing organisms)fixing organisms)

An ecosystem consists of two main components

Abiotic or Non-living components.

1. Inorganic substances

2. Organic compounds

3. Climatic factors

Biotic or Living components.

1. Autotrophs or Producers

2. Heterotrophs or Consumers

3. Decomposers or Saprotrophs

Structural aspects of ecosystem

ABIOTIC• light• Moisture• Water• Salinity• Oxygen supply• Soil

BIOTIC• Trees• Flowers• Cats• Dogs• you

Biotic-living factors that influence an ecosystem

Abiotic -non-living factors that influence an ecosystem

SunlightSunlight is the main energy source for life on earth. Also called autotrophs

Use light or chemical energy to make food1. Plants2. plant-like protists (algae)3. Bacteria

Photosynthesis-use light energy to convert carbon dioxide and water into oxygen and carbohydrates

(Remember: 6CO2 + 6H2O 6O2 + C6H12O6)

Chemosynthesis—performed by bacteria, use chemical energy to produce carbohydrates

Light Energy

Most energy comes from the sun

• Plants, also called producers, convert energy from the sun into food through a process called photosynthesis.  

• Photosynthesis is a process which uses water, carbon dioxide, and sunlight energy to make sugars.  Plants do this in special cells called chloroplasts.  These are usually green because of a pigment called chlorophyll.  Most photosynthesis happens in a plant's leaves, which is why they are green.

• When an animal eats a plant, some of the energy gets passed from the plant to the animal.  A food web shows this passage of energy, by showing what animals can eat what, and who gets eaten by who

MOISTURE• The amount of moisture in environment

varies from desert areas to lakes and oceans. All forms of life on earth requires water to live .

• In land environment the amount of available moisture is a function of precipitation, humidity and the evaporation rate

• In water environment the types of communities depends of water

Water

• Three form of Water Solid, Liquid or gas.• Large amount of heat is needed to change

the phases

Salinity• Ocean contains 3.5% of salts.

• The salt content is the major factor to determine what organisms will be found there

Figure 12-1

Fresh water organisms both plants and animals have a salt concentration in their body fluids and inside their cells higher than that of the water in which they live.

Some salt water organisms have salt concentration in their bodies or cells almost identical to that of ocean water

OceansThe ocean has many kinds of ecosystems. The

oceans are so large that the conditions in one part of the ocean are very different from the conditions in another part of the ocean.

Some ocean ecosystems are close to land and receive more sunlight. In the deep sea, sunlight cannot reach the ocean floor and the ecosystems are quite different.

The deep-sea anglerfish has a body that glows in the dark. It has a rod that glows and dangles in front of its mouth which attracts prey.

Estuaries and Salt Marshes

Estuaries are places where rivers flow into the ocean. Estuaries have water that is saltier than a river, but not as salty as the ocean.

Salt marshes are grassy wetlands at the edges of estuaries. South Carolina has many estuaries and salt marshes and is home to many living things such as fish, blue crabs, shrimp, and oysters.

Estuaries

Intermediate salt concentration.

Salt and fresh water meet

Dissolved gases: Oxygen• Condition:

– Marine animals need oxygen to survive

– Plants and animals need oxygen for respiration

• Respiration is a complex biochemical reaction.

• Glucose broken down by biological catalyst called enzymes The energy released is utilized by the cells.

If oxygen is available the material is fully broken down to CO2,H20 and Energy

soil

Soil

HUMUS

Relationship to soil quality?

Deciduous Forests• Deciduous forest ecosystems have trees such as oaks,

elms, and maples. These forests grow in moderately warm places where there is a lot of rain.

• The trees lose their leaves in the fall. Food and shelter are hard to find in the winter so, some animals hibernate.

Coniferous Forests

Coniferous forests are made up of mostly conifers, trees that have cones. These forests are found mostly in the northern part of the Northern Hemisphere.

Trees include spruces, hemlocks, pines, and firs.Animals include moose, deer, caribou, wolves,

bears, and elk.

Rainforests

Rain forests get large amounts of rain. Tropical rain forests are warm all year. These conditions enable large populations of many kinds of organisms to live there. Hawaii is the only state with tropical rain forests.

Grasslands Grasslands are ecosystems in which grasses

are the main plant life. Grasslands have fertile soil and have few trees. These ecosystems do not receive much rain during the year, so trees do not grow well.

How do organisms interact and depend on one another in an ecosystem?

A food chain shows how organisms get their food. The first organism in a food chain is a producer; consumers or decomposers follow

   Producer consumer decomposer

ConsumersA.Organisms that rely on other organisms for their energy and food supply

B. Also called heterotrophs

Herbivores-obtain energy by eating only plants

Carnivores-eat only animals

Omnivores-eat both plants and animals

Decomposers—breaks down dead organic matter

Feeding Interactions

A. Energy flows through an ecosystem in one direction—from the sun or inorganic compounds to autotrophs (producers) and then to heterotrophs (consumers)

B. Food Chain—series of steps in which organisms transfer energy by eating and being eaten

1. Arrows go in the direction of how energy is transferred

2. Start with producer and end with top consumeror carnivore

Ex: grass cricket frog raccoon

C. Food Web-network of food chains within an ecosystem

Hawks

Weasels Raccoons

Mice

Grass

D. Trophic Levels—each step in a food chain or food web

1. Level 1—Producers (autotrophs)

2. Level 2—Primary Consumers (herbivores)

3. Level 3—Secondary Consumers (carnivores or omnivores)

4. Level 4—Tertiary Consumers (carnivore—usually top carnivore)

Hawks

Weasels Raccoons

Mice

Grass

Food Webs

IV. Ecological Pyramids

A. Diagram that shows the relative amount of energy or organisms contained within each

trophic level of a food chain or web

Energy Pyramid

Biomass Pyramid

100%

10%

1%

0.1%

Represents amount of energy available at each level as well as amount of living tissue—both decrease with each increasing trophic level

Energy and Biomass Pyramid (together)

Heavy metalsEx: mercury

PesticidesEx: DDT (dichlorodiphenyltrichloroethane)

Organochlorides:Ex: PCBs

V. Ecological Interactions between organisms

A.Competition—when two organisms of the same or different species attempt to use an ecological resource in the same place at the same time.

Ex: food, water, shelter

Monkeys compete with each other and other animals for food.

Rams compete with each other for mates.

Until Americans introduced gray squirrels into parts of England in the early 20th century, red squirrels had been the only species of squirrel in the country. The gray squirrels were larger and bred faster and successfully competed for resources. Within a couple years of overlap in an area, the red squirrels disappeared.

B. Niche-the ecological niche involves both the place where an organism lives and the roles that an organism has in its habitat.

Example: The ecological niche of a sunflower growing in the backyard includes absorbing light, water and nutrients (for photosynthesis), providing shelter and food for other organisms (e.g. bees, ants, etc.), and giving off oxygen into the atmosphere.

The ecological niche of an organism depends not only on where it lives but also on what it does. By analogy, it may be said that the habitat is the organism’s “address”, and the niche is its “profession”, biologically speaking.

Worm’s Niche

“Address”—Soil, Ground, etc.

“Profession”– Mix-up soil

C. Predation—one organism captures and feeds on another organism

1. Predator—one that does the killing

2. Prey—one that is the food

D. Symbiosis—any relationship in which two species live closely together

1. Mutualism—both species benefit (WIN-WIN)a. Ex: insects and flowers

2. Commensalism-one member of the association benefits and the other is neither helped nor harmed.(WIN-0)

Example: barnacles on a whale

Commensalism

The Remora fish attaches to the shark and gets a free ride.

Birds build nests in trees.

3. Parasitism-one organisms lives on or inside another organism (host) and harms it.The parasite obtains all or part of its nutritional needs from the host. (WIN-LOSE)

Example: fleas on a dog

Parasitism

Wasp eggs on back of caterpillar.

Mosquito biting a human.

Sea lampreys feed on fluids of other

fish.

Mutualism, Commensalism or Parasitism

Food Chain

• A food chain describes a single pathway that energy and nutrients may follow in an ecosystem. There is one organism per trophic level, and trophic levels are therefore easily defined. They usually start with a primary producer and end with a top predator.

• Here is an example of a food chain: phytoplankton → zooplankton → fish → squid → seal → Orca (Killer whale)

Secondary, tertiary, quaternary consumers

• Secondary consumers are those that eat primary consumers, tertiary consumer secondary and so on…

• These consumers are either carnivores (sometimes insectivores or egg eaters), or ominvores

The extinct oviraptor (egg thief)

Scavengers• Scavengers are animals that do not

kill for a meal, but pick on “leftovers” from other animals

• Hyenas, vultures, crows, racoons, and some bears are scavengers

Decomposers• Decomposers or detritivores are organisms that

degrade or decompose dead or organic material in simpler molecules

• Fungi and bacteria are decomposers

FOOD WEB

A combination of different food chains is

called a food web.

Can you identify all the different organisms and

their levels?

The first level always has autotrophs

The second level has primary consumers – heterotrophs, herbivores.

The last level contains secondary, tertiary consumers – heterotrophs, carnivores, omnivores

10% of the energy from the 1st trophic level is available to the

2nd trophic level

90% of the energy at any given trophic level is used for growth and reproduction, and is eventually lost as heat.

Energy is eventually lost as heat on the top of the pyramid

Matter Cycles

Pyramid of Biomass or Numbers

Just like energy, biomass decreases at each level, because there is only enough energy at that level to support the biomass found there.

Predator - Prey• Lions and zebras, for example

• One hunts and kills, the other gets killed and eaten

Parasite - Host• Fleas and dogs for example• The parasite harms the host

and benefits from the relationship. The host is harmed, but not usually killed

Pathogen - Host

• A pathogen is a disease-causing agent, like a bacterium or a virus

E.coli H.I.V.

Mutualism• A symbiotic relationship where

two organisms are in a mutually beneficial relationship

• Examples: Lichens are not one organism but two – an algae and a fungus living as one. The algae provides the fungus with glucose in return for moisture from the fungus.

Clown Fish are protected from predator fish by the stinging tentacles of the anemone. The anemone receives protection from polyp-eating fish, like Butterfly Fish, which the Clown Fish chases away. The anemone also gets fertilizer from the feces of the Clown Fish.

Commensalism• In this relationship, one organism benefits but

the other is neither harmed nor benefited• Examples: Shark and remora,

More unusual examples of animal symbiosis

How nutrients cycle

• Nitrogen cycle• Carbon cycle• Water Cycle

These are some of the various nutrient cycles on Earth.

Nitrogen Cycle

Carbon cycle

Limiting Factors

• Any abiotic factor that limits the survivability of organisms in a particular ecosystem is called a limiting factor

• Examples: Water in a desert, light in the deepest parts of the ocean (abyssal and benthic zones), etc.

Food Webs

Food Chains

In this picture, how does the coyote depend on the sun?

Life Depends on the Sun

• Photosynthesis is the process by which plants, algae, and some bacteria use sunlight, carbon dioxide, and water to produce carbohydrates and oxygen.

B. Energy Pyramid shows relative amount of energy available at each trophic level

1. Organisms in a trophic level use the available energy for life processes (such as growth,

photosynthesis, cellular respiration, metabolism, etc.)and release some energy as heat

Remember: Every chemical process that happens in your body releases heat as a byproduct (ex: burning calories).

2. Rule of 10—only about 10% of the available energy within a trophic level is transferred to the next

higher trophic level

C. Biomass Pyramid—represents the amount of living organic matter at each trophic level