Ecology

EcologyEcology is the study of the relationships between plants, animals and their environment.

An example of organisms interacting with their environments is animals. They need plants for food and shelter. If food is scarce, animals will have to move elsewhere.

Ecosystems

In order to simplify the study of ecology the world is divided into smaller groups of plants, animals and environments. These groups are known as ecosystems.

Examples of ecosystems are deserts, tropical rainforests, grasslands and seashores.Habitats

The habitat of an organism is the place where it lives.

Populations and Communities

All the members of a particular type of plant or animal in a habitat form a population. For example all the primroses in a hedge form a population of primroses.

All the plants and animals in a habitat form a community.

For example, apart from crabs, many other types of animals and plants live on the seashore. All of these organisms form a community on the seashore.

Feeding Relationships in a Habitat

1) Producers: these plants make their own food.

2) Consumers: these are animals that get their food from plants or other animals.

Herbivore - animals that eat only plants e.g. greenfly, sails

Carnivore - animals that eat both plants and animals e.g. sparrows, hawks

Omnivore - organisms that feed on dead plants and animals e.g. bacteria, fungi

3) Decomposers: these are organisms that break down dead materials e.g. bacteria, fungi

Food Chains

A food chain is a list of organisms in which each organism is eaten by the next one in the chain.

Grass - Rabbit - FoxFood Webs

A food web is a series of interconnecting food chains.

Adaptation

Adaptation is when an organism has characteristics that make it well suited to its environment.

For example, in a hedgerow, ladybirds are brightly coloured to warn predators of their bitter taste, and nettles have stinging hairs to prevent them form being eaten by certain animals. Competition

Competition takes place when organisms struggle for the same resources in the habitat.

For example, plants compete for light, water, space and minerals, and animals compete for food, territory, mates and shelter.

Interdependence

Interdependence means that living things depend on each other for survival.

In any habitat, many organisms depend on each other.

Animals depend on plants for shelter and for food.

Plants also depend on animals. e.g. to transfer pollen (bees and flies), and to scatter their seeds (blackbirds).

Habitat Study

The study of a habitat involves the following steps;

1) Draw a simple map of a habitat or use a photograph.2) Measure and record the environmental (non-living or abiotic) features in the habitat.

3) Identify and list all the organisms (biotic features) in the habitat.

4) Collect the samples of these organisms that cannot be identified in the habitat.

5) Estimate the number of each organism in the habitat.

Identifying Organisms

Organisms can be identified by using a suitable key or by comparing them to drawings or pictures in a book.

Estimating the number of organisms in a habitatA pooter, a beating tray and a pitfall trap can be used to collect animals.

A quadrat is a square used to estimate the number of plants in a habitat.

A line transect is a rope marked at regular intervals and laid out across a habitat to estimate the number of plants present.

Conservation

This is the protection and wise management of natural resources.

Pollution

Pollution is the addition of harmful substances to the environment.Micro-Organisms

Micro-organisms (microbes) are tiny living things. Microbiology is the study of microbiology.

Examples of micro-organisms are viruses, bacteria and fungi.

Viruses

Viruses are the smallest type of micro-organism.

They are unable to reproduce by themselves.

They are parasites (they get their food from living things).

Diseases such as flues, mumps, chicken pox and mumps are all caused by viruses.

They are not killed by antibiotics.

Viruses are controlled by antibodies produced by white blood cells.

Bacteria Bacteria are larger than viruses.

They require food, water and a suitable temperature and pH in order to grow.

They are divided into aerobes (need oxygen) and anaerobes (do not need oxygen).

Bacteria reproduce asexually.

They may be parasites (feeding on living things) or saprophytes (feeding on dead things). They may be useful (for decay, producing foods or in biotechnology).

They may be harmful and cause diseases which destroy food and crops.

TB, food poisoning, tetanus and chorea are all cause by bacteria.

Bacteria can be controlled by using antibiotics.

Antibiotics

These are chemicals made by micro-organisms which kill or prevent the growth of bacteria.

Fungi

Fungi do not contain chlorophyll.

They grow as single cells or threads.

They may be useful (cause decay, may be eaten, make alcohol and used in bread making).

Fungi may be harmful (cause diseases, may be poisonous, rot food).

An example of an ailment caused by fungi is athletes foot.

Biotechnology

Biotechnology is the use of living things or their parts to produce useful products.

Industrial Uses of Biotechnology

using yeast to produce alcohol

using bacteria to produce enzymes for cleaning clothes.Medical Uses for biotechnology using bacteria and fungi to produce antibiotics

using micro-organisms to produce hormones antibodies and blood clotting chemicals.Fuels

A fuel is any substance that can be burned to produce energy.

Fossil Fuels

Fossil fuels are produces over millions of years.

They are formed from the remains of plants and animals.

Examples of fossil fuels are coal, crude oil, and natural gas.

Fossil fuels are mainly made up of two elements: hydrogen and carbon. Fossil fuels are known as hydrocarbons.

The Greenhouse Effect Our atmosphere behaves like the glass in a greenhouse.

This effect keeps the average temperature of the earth relatively steady. Some of the gases in the air are known as greenhouse gases.

Without them, the earth would be much colder.

The main greenhouse gases are carbon dioxide, methane and water vapour. Global Warming - Effects

An increase in greenhouse gases is leading to global warming.

Global Warming could lead to major changes is climate.

e.g. melting of the polar ice caps, rise in sea levels, flooding.

Acid Rain

Acid rain is caused by the burning of fossil fuels which produce sulphur dioxide and oxide of nitrogen.

These gases react with rain water, producing sulphuric acid and nitric acid.

Effects of acid rain

Acid rain causes minerals such as aluminium to be washed into lakes, killing fish.

Acid rain attacks trees and soil.

Acid rain attacks limestone buildings and structures, causing them to corrode quickly.

How to reduce the effects of the Greenhouse Effect and the effects of acid rain

Reduce the use of fossil fuels as a source of energy.

Use alternative sources of energy such as wind or solar.

Cars are now fitted with catalytic converters which convert oxides of nitrogen into harmless nitrogen.