Biomes

A biome is a large community of organism that have adaption for a specific environment and
climate. They are distinct biological communities that are formed in response to a shared
physical conditions or climate. They can also be said to be ecologically defined areas which
are climatically and geographically similar in characteristics, appearance, communities of
plants, animals and soil organisms.

Biomes are defined by factors such as plant structures (trees, shrubs, grasses), leaf types
(such as broadleaf, needle leaf) plant spacing (forest, woodland, savanna) and climate.
Climate is a major factor determining the distribution of terrestrial biomes. Among the
important climatic factors are: Latitude, Humidity, Seasonal Variations (especially rainfall
and temperature), and Elevation. We have 2 major biomes in Nigeria namely; Forest and
Savannah. They are also referred to ecological zones.

Ecological Niche
Ecological niche is a term for the position of a species within an ecosystem, describing both
the range of conditions necessary for existence of the species, and its ecological role in the
ecosystem. Ecological niche comprises of all interactions between a species and the
environment (biotic and abiotic), and thus represents a very basic and fundamental ecological
concept. This definition indicates that the concept of niche has two sides: one concerns the
effects of environment on a species, the other the effects a species has on the environment. In
most of ecological thinking, however, both meanings are implicitly or explicitly mixed. The
reason is that ecology is about interactions between organisms, and if persistence of a species
is determined by the presence of other species (food sources, competitors, predators, etc.), all
species are naturally both affected by environment, and at the same time affect the
environment for other species.

Unlike the habitat where an organism is found, the niche is a complete description of how the
organism relates to its physical and biological environment. That is, the role of an organism
within a community, its behaviour and the way in which the behaviour changes at different
seasons and different times of the day. It can be seen as a method of ‘making’ a living within
each functional category in the operation of the ecosystem. The factors that make up an
organism’s niche determine whether it can exist in a given ecosystem and also with how
many species it can exist together with.
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 ENVIRONMENT
The term Environment which means surroundings is considered as a composite term for the
conditions in which organisms live, procreate and survives. It basically consists of air, water,
food and sunlight which are the basic needs of all living things. The environment also
consists of both biotic and abiotic substances. Environment creates favourable conditions for
the existence and development of living organisms.

For a given organism the environment includes all the surrounding physical and biological
factors with which it interacts. The factor is any external force, substance, or condition that
affects organisms in anyway. Thus, environment is the sum total of everything that directly
influences the animal‘s chances of survival and reproduction. Environment is a very broad
concept. Everything that affects an organism during its life time is collectively called its
environment. The environment of an organism consists of all the factors in its surroundings
that affect it. Such factors include the:

– Place where the organism lives and physical conditions of the place like light
intensity, temperature, humidity etc.
– Food, water and air that it takes in for its activities
– Animals that prey on it, and
– Diseases that affect it

ENVIRONMENTAL FACTORS AND THEIR EFFECTS

Environmental factors include temperature, food, pollutants, population density, sound,
light, and parasites. The diversity of environmental stresses that have been shown to cause
an increase in asymmetry is probably not exclusive; many other kinds of stress might provide
similar effects. They are basically divided into two; Biotic and Abiotic.

Abiotic
• Temperature: The narrowness of the temperature range over which biochemical
processes can function efficiently implies that organism, wherever they live, must
have the necessary physiological or behavioral adaptations to combat the extremes of
environmental temperatures.
• Water: The extent to which an organism is dependent on an abundant water supply
depends on its requirements and its ability to conserve it in adverse conditions.
Organisms living in dry habitats generally have good water conservation

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 • Light: This is essential for all green plants and photosynthetic bacteria, and for all the
animals dependent on plants. Plants have numerous adaptations for obtaining
optimum illumination.
• Humidity: It is important because it can affect the rate at which water evaporates
from the surface of an organism, which in turn influences its ability to withstand
drought.
• Wind and Air currents: It is applicable to plants. Only plants with strong root
systems and tough stems can live in exposed places where winds are fierce.
• Soil

Biotic
An organism biotic environment is made up of all the other organisms with which it comes
into regular contact. Below are some examples;
• Predation: An organism may feed on, or be fed on by, other organism. In
such case the distribution of feeder and fed are related. Thus herbivores are
only found where there is suitable plant food; carnivores plant where there are
suitable insects predators where there is suitable prey.
• Competition: Organisms frequently compete with one another for such
commodities as food, light, water, shelter, mate or resting site. Competition
has resulted in all manner of adaptations.
• Organisms may use another as a habitat. Typical example is seen in parasitism

MEASUREMENT OF ENVIRONMENTAL FACTORS

INSTRUMENT FUNCTIONS / USES
1 Rain gauge Measuring the amount of rainfall
2 Thermometer Measures the lowest and highest temperature of the day
3 Anemometer Measuring the speed of wind
4 Wind vane Indicate the direction of wind
5 Hygrometer Measures relative humidity
6 Barometer Measures pressure
7 Photometer or light meter Measures light intensity on land
8 Hydrophotometer Measures light intensity in water
9 Colorimeter or pH indicator Measures acidity or alkalinity of soil or solution
10 Tullgren funnel Compares the numbers and types of animals in difference
soil
11 Baermann funnel For collecting tiny organisms that live in soil water
12 Sacchi disc Measures the turbidity or transparency of water
13 Tape Measures height and length of objects
14 Thermograph For long period recording of temperature and relative
humidity
15 Meter rule Measures the length of objects
16 Water speed meter Measures speed of water flow
17 Slope gauge Measures slope of an area of land

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