Ecology#BIOLOGYRESOURCENOTES

A LESSON PREPARED BY: MR.HISHAM ZULFADHLI , SUBJECT HEAD OF BIOLO GY

Agenda Biotic & Abiotic Factors

The Food Chain

The Food Web

Energy Flow

The Pyramid of Numbers

The Pyramid of Biomass

The Pyramid of Energy

Biotic Factors• Biotic factors are all the living things or their materials that directly or indirectly affect an organism in its environment. This would include organisms, their presence, parts, interaction, and wastes.

•Factors such as parasitism, mutualism, disease, and predation would also be classified as biotic factors.

•Each biotic factor needs energy to do work and food for proper growth.

•Biotic components include:

I. Producers: Autotrophs use photosynthesis to convert solar energy into chemical energy to be stored as glucose (Carbohydrates).

II. Consumers: Heterotrophs depend on autotrophs for energy

III. Decomposers: Detritivores break down chemical from producers and consumers into simpler form that can be reused. (E.g. Decaying matter)

Abiotic Factors• Abiotic factors include physical conditions and non-living resources that affect living organisms in terms of growth, maintenance, and reproduction.

•Abiotic factors can include water, light, radiation, temperature, humidity, atmosphere, and soil.

•Soil

•Soil is the outermost layer of the surface of the earth in which plants grow. It is composed of eroded rock, mineral nutrients, decaying plant and animal matter, water and air.

•This abiotic factor is likewise important in crop farming and is treated under the heading Soil and Climatic Adaptation or Requirement of crops.

•Water

•Rainfall is the most common form of precipitation. It is the falling of water in droplets on the surface of the Earth from clouds.

•As with other climatic factors, water can possibly cause unfavourable effects on plant growth and development. Excess water in the soil can injure flood prone plants, like corn (maize), due to lack of oxygen.

Abiotic Factors•Light

•Light is the primary source of energy to almost all ecosystems. Light energy is used by producers to produce their own food by photosynthesizing.

•Light quality refers to the specific wavelengths of light; light intensity is the degree of brightness that a plant receives; and day length is the duration of the day with respect to the night period.

•Temperature

•Temperature influences the distribution of plants and animals. The occurrence of frost is an important to determine the distribution of plants as most of the plants cannot prevent freezing of their tissues.

•Excessively low temperatures can also cause limiting effects on plant growth and development.

Abiotic Factors•Wind

•Air currents or winds are a result of interaction between expansion of hot air and convection in the mid latitudes. This complex interaction influences the earth's rotation and results in a centrifugal force which lifts the air at the equator.

•This climatic factor serves as a route of pollen from one flower to another thus assisting in the process of pollination.

•Atmospheric Gases

•Atmospheric gases like oxygen, nitrogen and carbon dioxide.

•The oxygen and carbon dioxide in the air are of particular importance to the physiology of plants. Oxygen is essential in respiration for the production of energy that is utilized in various growth and development processes. Carbon dioxide is a raw material in photosynthesis.

Abiotic Factors•Topography

•Topography is a non-living factor. It includes the physical features of the earth such as the land elevation, slope, terrain, mountain ranges and bodies of water.

•The altitude or elevation of the land with respect to the level of the sea surface influences plant growth and development primarily through temperature effect.

•Climate

•Climate of a region includes the average rainfall, temperature and the patterns of winds that occur. Climate is one of the most important abiotic factors of an ecosystem.

•Temperature of an area and the precipitation factor determines whether the region is grassland or a forest.