Biology Form Two Notes – Balance of Nature

These Biology Form Two notes cover Balance of Nature. The material is organised in clear sections for easier reading, understanding and revision.

The Natural Environment

The Concept of Natural Environment

Natural environment is made up of all living and non living things that occur naturally on earth. An organism living anywhere in any environment is affected by the things around it such as air, water, animals, plants, microorganism, stones, rock, soil, clouds and the sun. everything around it in fact makes its natural environment. It is important to understand that the environment

includes all living things as well as non living things IMPORTANT TERMS

Ecology: is the branch of biology that deals with studying interaction oforganisms with their

environment

Population: is the total number of organisms of the same species living in a certain area.

Example the number of frogs in a pond

. Community: this refers to the sum of total of all population of different organisms living in a

specific called habitat

Habitat: is the specific area where an organism is found and adopted. i.e it is an appropriate for

the certain community example an ocean, grassland, and a pond

Ecosystem: refers to a natural unit made up of living and non living things whose interaction

Biotic And Abiotic Components Of The Environment

There are two components of environment;

. Biotic (living things) Abiotic (non living things)

Biotic Component

These are living components in the environment such as animals, plants, fungi, and microorganisms. These organisms interact together in number of ways and these ways of

interaction include the following;

Competition, that organisms must compete for limited resources in struggle for life. For an

organism to survive in an ecosystem it must compete with partner for the limited resources.

Predation Is the system in which one organism utilize the other as food. The eater is a predator

while the eaten is a prey and a number of predators and preys regulate each other

Symbiotic relationship This is where there is a close relationship or association between organisms this association could take various forms like mutualism, commensalism, and parasitism

Adaptation Adaptation has enabled organisms to survive. They may be anatomically structurally physiologically or behavioural. Eg some organisms are poisoners to their predator while others

while others develop warming colouration ABIOTIC COMPONENTS

These include non living organisms that are found in ecosystem. Example air solar, energy, soil, and nutrients. Generally abiotic components of an ecosystem consist of physical environment

and they are as follows:

Climatic factor:Several change of climatic condition influence or determine the survival of

organisms in ecosystem such condition include temperature, humidity, pressure ete

Aquatic condition:Changes in the aquatic environment and the nature of environment it is self determined by the type of organism found in the area such a changes include water current, wave

action, salinity, etc

Light condition factor:These affect much plant population where photosynthetic process depend on the availability of light.

Soil factor/condition:These are also adaphic factors and they include soil texture, soil structure

and soil pH

Various Organism in their Natural Environment in the Community

] Activity 1

Identify various organism in their natural environment in the community

IMPORTANCE OF NATURAL ENVIRONMENT

It is a source of food to organisms

It provides shelter and security for organisms

It allow living and non living things to interact

It provides an appropriate setting for organisms to reproduce andincrease in number.

Topic Three

Balance Of Nature

Interactive of Organisms in the Environment

Ways in Which Living Organisms Interact with the Non Living Component

of the Environment

The following are the interaction of organism in the environment . Ground water and water from rain flow into streams and rivers The stream and rivers flow into lakes and ocean Water evaporate into the atmosphere from lakes and ocean and from plants through transpiration The evaporated water precipitates to form water vapor which condenses to form clouds Wind causes clouds to move for example from above the ocean to above the land

Rain fall and absorbed by plants or form grounds water, and the cycle begins again.

Interaction Among Living Organisms

Competition:That organisms must compete for limited resources in struggle for life. For an organism to survive in an ecosystem it must compete with partner for the limited resources

_Example lions and leopards both hunt zebra, and so they are competitors

Predation:Is the system in which one organism utilize the other as food. The eater is a predator while the eaten is a prey and a number of predators and preys regulate each other. e,g cats eat

mice

Symbiosis:This is where there is a close relationship or association between organisms this

association could take various forms like mutualism, commensalism, and parasitism

Mutualism is a relationship where two organisms benefit each other for example the rhizobium

bacteria in the root nodules of legumes fix nitrogen into nitrate to be used by the plant

Adaptation: Adaptation has enabled organisms to survive. They may be an atomically structurally physiologically or behavioural. Example some organisms are poisoners to their predator while

others while others develop warming coloration

. Commensalism is the interaction that is beneficial to one organism and is neutral to the other

organism. For example when a bird builds a hole or a nest in a tree

. Parasitism is the association where one organism benefit while the other is harmed. Example

plasmodium that cause malaria to human

Food Chain and Food Web

The Meaning of Food Chain and Food Web

FOOD CHAIN

Is the sequence of living things in which each organism is the food of the next in the sequence. Grass +Zebra—Lion

Maize plant—>grasshopper—>Frog

Food Web

Is made of interconnecting food chains

The Components of a Food Chain and Food Web

Producers

Are organism that can manufacture their own food for example green plants and green bacteria Primary consumers

They are organisms that feed on producers for example rabbits, buffalo andsheep

Secondary consumer

They are organisms that feed on primary consumer

Decomposers

These organisms feed on dead matter and break it down thereby facilitating decomposition. For

example bacteria and fungi

The Difference between Food Chain and Food Web Distinguish food chain from food web

Differences between food chain and food web

pod chain Food web

It consists of the single straight pathway through which food 1. It consists of a number of inter connected food chains

ergy travels in an ecosystem through which energy travels in an ec

Usually members of the higher trophic level feed upon a 2. Usually members of the higher trophic level feed upon

gle type of organisms of lower trophic level many organisms of lower trophic level

Isolated or separate food chains increases the instability of the 3. Presence of complex food webs increases the stability of the

fosystem ecosystem

It does not have any effect on improving the adaptability and — 4. More complex food webs improves the adaptability and

mpetitiveness of the organisms competitiveness of the organisms

Diagrammatic Representation of a Food Chain and Food Web

Construct a diagrammatic representation of a food chain and food web

Food chain

Food Chains And Food Webs

human being

phytoplankton

Food chain example Grass —-cow—>human being Phytoplankton—fish—bird

Food web

Food Chains And Food Webs

salamander

maize stalk borer

The Significance of Food Chain and Food Web in Real Life Situation

The following are the significant of food chain and food web

Food chains and webs help in the flow of energy from producers to consumers and from one

trophic level to another, without which energy flow would be impossible.

Food chain studies have had an important role in ecotoxicology studies tracing path ways and

biomagnifications of environmental contaminants.

Learning how the food chain works enable us to understand the importance living organisms that make up the food chain and how the ecology is balanced. This is crucial since any interruption in

food chain could lead to ecosystem imbalance.

4. Food chains and webs show the flow of energy through an ecos

5. Understanding the effect of polluting the natural environment enable us to avoid or control

environmental pollution so as to maintain natural ecosystems.