Ecosystems and biomesNeeds of living things

Objectives

Student will be able to:• Describe the basic needs of living organisms• Define Ecosystems and Biomes• Describe the energy flow in ecosystems

Basic needs of living organisms

• water, • air, • shelter, • food, • minerals,• and decomposers.

Water

• Water is needed to transport nutrients to cells and carry waste products away.• Evaporating water helps moderate body temperature in humans.• Water is also essential for key processes in plants.

Shelter

• On Earth, gravity holds our atmosphere in place and makes possible the biosphere, our global home. • In addition, almost all humans live in structures that moderate climate

changes and make life more pleasant.• Anyone who ventures out of the biosphere must take shelter along.• During space walks, astronauts’ suits provide conditions needed for

human life.

Air• A mixture of gases (nitrogen (78%),oxygen (20%), carbondioxide (.03%),

and other gases(1.97%)) make up air.

Air

• Nitrogen is required for building structural protein, enzymes, and other organic molecules. • In addition, nitrogen dilutes the oxygen in our atmosphere. That is, it

slows down combustion, allowing materials to burn at a controllable rate. • Oxygen is required for the breakdown of food• Carbon dioxide is essential for the photosynthesis process.

Minerals (Soil Nutrients)

• Minerals are required in order to grow food.• Nitrogen, phosphorus, potassium, iron, zinc, manganese, and

molybdenum, are contained in some of the minerals and natural solutions that provide the necessary nutrients for plant life. • Through the food chain, they also provide the minerals and elements

essential for a healthy human body.

Food

• Humans need a variety of foods. • Plants and animals provide carbohydrates and fats for energy, • Proteins for energy and tissue building, • Vitamins for specific biological functions, • and minerals and chemical elements that are indispensable for life.

Decomposers/ Detritivores

• The organisms of decay (mainly bacteria and fungi) recycle sewage and dead plants and animals; • this keeps the soil fertile. • Without decomposers, Earth would quickly be covered in dead

organisms.

Ecosystems

• Ecosystems consist of groups of organisms interacting in a variety of ways with each other and with the nonliving environment.• The interactions within each ecosystem are unique to that ecosystem.

Many of these interactions are driven by each organism’s basic need for food.• Ecosystems consist of many communities living together in the same

area.• Biome a large ecosystem characterized by a distinctive type of climate,

soil conditions, and biological community adapted to those conditions.

Ecosystems –Habitat and Niche

• The place where an organism lives is its habitat. • What an organism does, or how it affects and is affected by its

habitat, is called its niche.• For example, the grassland community is a habitat suitable for

antelope. It includes nutritional grasses; it also includes open spaces that allow the antelope to escape its predators. • If you were to study all the activities of the antelope, you would be

studying the niche of the antelope.

Ecosystem

• The environment determines the boundaries of an ecosystem.• That is, as the environment (moisture, soil type, temperature, and• wind) changes, so does the ecosystem. • The boundaries may be the result of change in moisture, such as that

found between a marsh and the adjacent dry land or between grassland and an adjacent forest. • The separation of ecosystems is not often as distinct as that between

a pond ecosystem and the adjacent forest ecosystem.

Ecosystem –Energy flow• Ecosystems are dynamic (changing) systems in which there is a constant

movement of energy and materials. • However, within this flow of energy, environmental resources and

organisms tend to be in balance• Producers (Plants)• Macroconsumers (herbivores, Carnivores, omnivores)• Microconsumer and Detritivores e.g. bacteria, fungi, earthworms, beetles)

Ecosystem –Feedback loop• If the primary consumers eat too much grass (or too many of the

producers) and deplete their food reserve, then many of the consumers will die, until a balance is reached between the number of consumers and the amount of food available.• Systems function in cycles, with each component eventually feeding back to influence the size or rate of itself. • A positive feedback loop tends to increase a process or component.• A negative feedback loop diminishes a process or component.

Energy source

• Ecosystems must be powered by an energy source. • The sun is the source of the radiant energy that supports the ecosphere.

summarizes what happens to the solar energy that strikes the earth.• Note that 31 percent is directly reflected back into space. • Forty-seven percent is converted into heat after being absorbed by such

things as the ground, the oceans, and roofs. • Twenty-two percent evaporates water, which causes precipitation. • About 0.2 percent drives all the winds, waves and the ocean’s convection

currents. • Less than 0.1 percent is used in the photosynthesis process

Earth’s Solar Budget

Photosynthesis• Photosynthesis is the process by which plants use light energy to convert

carbon dioxide, water, and various minerals into the sugars and starches that make up plant cells. • Through photosynthesis, plants produce the food and oxygen that sustain

all life, including their own.• For this reason, plants are called producers. • Photosynthesis is summarized by the following general equation:• Carbon dioxide + water +minerals + energy → food (plant cells) + oxygen• or• 6 CO2 + 6 H2O + solar energy → C6H12O6 (glucose) 6 O2

Respiration

• Respiration is the process organisms use to break down food to obtain energy. • It is the reverse of the photosynthesis equation and may be

represented by the following general equation:• Food + oxygen → carbon dioxide + water+ minerals + energy• or• C6 H2O6 (glucose) 6 O2 → 6 CO2 + 6 H2O + energy• As organisms process food, they give off carbon dioxide, water, and a

variety of minerals.