An Environment Consists Living Organisms and Non

7/27/2019 An Environment Consists Living Organisms and Non

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An environment consists living organisms and non-living factor. The

living organisms in an environment are called biotic components.The

non-living factorsare called abiotic components. Living organisms

interacts with one another as well with the non-living factors to form a

stable and balance system known as ecosystem.

ABIOTIC COMPONENTS

Abiotic components are the non-living components. These are

physical factors that are non-living in the ecosystem such as :-

i. pH

ii. temperature

iii. light intensity

iv. humidity

v. topography and

vi. microclimate

pH

-The distribution of organisms can be influenced by the pH value of

the soil or water in habitat.

- Some plants such as pineapple plants and fern grow well in acidic

soil.

- ther plants such as coconut palms and cacti grow better in alkaline

soil.

- !ost organisms live well in neutral habitats

-!ost a"uatic organisms can be killed if the pH changes.

Temperature

- Temperature affects the distribution of organisms as most

physiological activities are affected by temperature.

- !ost living organisms live within the temperature range #$%c to &$%c

- 'hysiological activities come to a halt at temperature higher than

&$%c as the en(ymes cataly(ing these activities are denatured.


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Light intensity

- Light intensity affects the distribution of plants as plants use light for

photosynthesis.- Small animals such as earthworms and lice move away from light.

Humidity

- Humidity refers to the concentration of water vapour in the

atmosphere

- Humidity is usually higher at night

-!ost plant and animals prefer humid conditions.

!icroclimate

- !icroclimate refer to the climate of a microhabitat such as under a

rock or in a hole

- )t may be different from the climate of a macrohabitat

Topography

- Topography refers to the physical features of the land such as the

gradient* altitude and aspect of a region.


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BIOTIC COMPONENTS

The organisms can be grouped into three :-

i+ 'roducer

ii+ ,onsumer

iii+ ecomposer

'roducer

- 'lant* algae and certain bacteria are producer

- 'roducer or autotrophs can synthesise organic substance or food

through photosynthesis using sunlight as the source of energy.


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,onsumer

- Human and animal are consumer or heterotroph

-

They unable to make their own food- They obtain food and energy directly or indirectly from producer

a+ 'rimary consumers are herbivores as they obtain food and

energy from producers.

b+ Secondary consumers are carnivores as they obtain food and

energy by feeding on primary consumer

c+ Tertiary consumers are carnivores as they feed on secondary

consumer.

ecomposers

- acteria and fungi are decomposers

- They break down the remains of dead organisms to obtain nutrients

as well as to release simpler substance to be used by plants.

OO! C"AIN# OO! $EB AN! T%OP"IC &E'E&S


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/+ A food chain is a se"uence of organisms in which energy is

transferred from one organisms to another

#+ A food chain usually starts with a producer.

0+ The position of an organism in each level of a food chain is known as

a trophic level.

&+ A food chain can be represented using a pyramid of number.

$+ )n an ecosystem* the feeding relationship is more complete. 1ach

animal usually feeds on or eaten by more than one type of

organisms.

2+ Hence* a few food chains are interconnected to form a food web.

3+ )n an ecosystem* the producer converts solar energy into chemical

energy through photosynthesis.

4+ 5hen the primary consumers feed on producers* part of the energy

stored is passed on. 6ormally* about /78 of the energy is

transferred. About 978 of the energy lost to the environment lost to

the environment

9+ 1nergy obtained is used for growth* reproduction* movement and

other activities as well as to maintain body temperature.

/7+ 1nergy is lost to respiration* ecretion* and defaecation.


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INTE%ACTION BET$EEN BIOTIC COMPONENTS

Symbiosis () Symbiosis is a close long-lastinginteraction bet*een t*o or more+ifference species living toget,er.

) T,ree types of symbiotic relations,ips

a) Commensalism / one speciesbenefits *,ile t,e ot,er is0naffecte+

b) Parasitism- one species benefits*,ile t,e ot,er is ,arme+

c) M0t0alism / bot, species benefit

Commensalism ,ommensalism is an interaction betweentwo organisms in which one organism;commensal+ benefits from the

interaction and other ;host+ neitherbenefits nor is harmed.

The host often provides a habitat andtransportation for the commensal.

Two eamples of commensals are epi(oicand epiphytes.

1pi(oic are animal which live ascommensals on the outside of otheranimals.

1amples of epi(oic :i+ arnaclesii+ The remora fish

1piphytes are plants which grow on thesurface of other plants to obtainsufficient sunlight and air. They do notabsorb food from their host.

1amples of epiphyte are:i+ ird%s nest fernii+ orchids

Parasitism 'arasitism is an interaction between twoorganisms in which one organism

;parasite+ benefits and the other ;host+ isharmed.


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There are two types parasites* namelyectoparasites and endoparasites.

1amples of ectoparasites include:i+


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Saprophytism Saprophytism is a type of interaction inwhich a living organism obtain food fromthe dead and decaying remains of otherorganisms

Saprophytes are plants which feed ondecaying organic matter.

1n(ymes are secreted to digest theorganic matter before the nutrients areabsorbed.

Sapro(oites are animal which feed ondecaying organic matter

'rey-predatorinteraction

'rey-predator interaction is a type ofinteraction in which an animal;predator+hunts and eats another animal;prey+

'redators are usually bigger* strongeranimals with sharp vision* sharp clawsand canine teeth. They usually movefast.

The prey-predator interaction isimportant in keeping the population ofboth the prey and predator in a dynamice"uilibrium.

,ompetition ,ompetition is an interaction betweenorganisms living in the same habitat andcompeting for same resource which arelimited.

'lants compete for water* light* nutrientsand space.

Animal compete for food* space andbreeding mates.

There are two types of competition:a+ )ntraspecific competitionb+ )nterspecific competition.

)ntraspecificcompetition

)ntraspecific competition refers to thecompetition among organisms of the


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same species.

An eample for intraspecific competitionis the competition among ryophyllumsp. 'lants. The parent plant reproduceraseually by producing young plants

from buds on fallen leaves. The youngplant crowd around the parent plant*competing for water* space* nutrientsand light.

An intraspecific competition is usuallymore intense than an interspecificcompetition because the members of thesame species share the same resources.

Interspecificcompetition

)nterspecific competition refers tocompetition among organisms of

different species. An eample of interspecific competition

is the competition between to species of'aramecium* '. aurelia and '. caudatum

5hen both species of paramecium arecultured separately* each populationshows a sigmoid growth curve. 5henthey cultured together* '. Aurelia wins asit reproduces at a faster rate. '.caudatum loses in the competition and iseventually eliminated.


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T"E P%OCESS O CO&ONISATION AN!S1CCESSION IN AN ECOS2STEM

o 1,S>ST1!

/. An ecosystem is a dynamic system formed by the interactions of

organisms with one another and with the non-living factor of the

environment.

#. The biotic components are in balance with one another as well as

with the abiotic components.

0. 1amples of ecosystem include a pond* a beach* a field* or a

rainforest.


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CO&ONISATION AN! S1CCESION

/. The coloni(ation is a process in which living organisms arrive at a

newly formed area to live* reproduce and take control of the area

which was devoid of life earlier.

#. The first species of organism to colonise a new area is called the

pioneer species.

Nic,e The niche of an organism is the roles and activities of the organism in

its habitat. Two organisms sharing the same habitat may havedifferent niches.

An organism can be classified as a producer* consumer ordecomposer based on its role in a food chain.

"abitat A habitat in the natural environment in which an organism lives and

obtains its basic resources such as food and shelter.

1ample: a pond is a habitat for fishes prawns* planktons and othera"uatic organisms.

Comm0nity

A community consists of different populations of plants and animalsliving and interacting in the habitat of an ecosystem.

A community is named after the dominant species or the physicalfeature of a habitat. 1ample: rainforest community.

Species A species is a group of organisms which can interbreed to produce

fertile offspring.

1ample: avicennia sp.* sonnneratia sp.* rhi(ophora sp.*

Pop0lation A population consists of organisms of the same species living in the

same habitat at the same time.

1ample: a population of snails living in a garden.


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0. The pioneer species have special adaptation to survive in

unfavourable land conditions

&. The pioneer species gradually changes the conditions of habitat*

modifying it into a conducive habitat for other species but not for

themselves. The modified habitat is suitable for successor species

which gradually replace the pioneer species.

$. The succession species grows and changes the habitat* making it

suitable for other better adapted species.

2. As time passes* a succession process continues until a clima

community is formed.

3. Succession is a process in which one community which is better

adapted replaces another community which is less adapted to the

change environment.

4. A clima community is a balanced and stable community which is in

e"uilibrium with the environment.

9. A clima community takes many years to form. )t has little or no

changes in its species structure.


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Mangrove s*amps Swamps are formed by deposition of mud and silt carried down by

the river. )t is found at the estuary that is where the river meets the

sea.

nly mangrove tree are able to colonise the soft* water logged*

muddy soil which has a low oygen level but high salt concentration.

!angrove tree have adaptive structures to overcome the harsh

conditions in swampy area.

Coloni3ation an+ s0ccession in a mangroves*amp

'ioneer species Avicennia sp. And sonneratia sp. Are pioneer species

1tensive cable root systems trap mud and silt as well as organicmatter from decaying plants.

Soil becomes more compact and the shore level is slightly raised

Soil is firmer and less waterlogged.

Succession by =hi(ophora sp. The higher* drier and compact soil favours the growth of rhi(ophora

which replace the pioneer species.

'rop root system of =hi(ophora sp. Traps more mud and silt. Humusis formed from dead pioneer species and decaying leaves fromrhi(ophora sp.

Soil firmer* more compact and fertile

Shore level is raised. Soil is drier and is less saline.

Succession by ruguiera sp. ruguiera sp. =eplace rhi(ophora sp. 5hen the soil is drier* harder

and more compact.

uttress root system traps more silt and mud

The shore etends futher to the sea.

Succession byterrestrial plants 1ventually a tropical rain forest which is the clima community is

formed.


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Pop0lation ecology

This is a branch of ecology that studies the structure and dynamic

populations

A population%s si(e and how it change over time are determined by

abiotic factors* biotic factors* birth rate* death rate* immigration and

emigration of members of a population.

To estimate the population si(e* a sampling techni"ue is used. This

involves collecting* counting and making observations on the

organisms studied.

The sampling techni"ue to estimate the population si(e of plants is

"uadrat sampling techni"ue. The sampling techni"ue to estimate

the population si(e of an animal species is the method of capture-

mark release and recapture.


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40a+rat sampling tec,ni50e

/. ?uadrat Sampling Techni"ue is used to estimate the population si(e

of plants as well as immobile animals. A "uadrat is a s"uare frame

made of wood* plastic or metals of a known area such as / m ;/ m

/ m+. The si(e of the "uadrat depends on the si(e and type of

organism.

#. The area covered by the "uadrat is the sample to be studied. The

"uadrat is placed randomly in the habitat studied. A number of

samples* usually ten* are set up to obtain an accurate result

0. The distribution of organism can be determined in three ways as

follows.

a+


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#. )nitially* a number of animals is captured* marked and release into

the general population.

0. After a few days* a second sample is taken and the number of

marked animals is recorded. The population si(e of the animal is

calculated using the following formula.

&. The assumptions made are as follows.

i+ The marked organisms can freely mi with unmarked organisms.

ii+ The individuals of second sample and caught randomly.

iii+ The substance use to mark the animal cannot be deleted easily*

is not poisonous and does not affect the animal%s activity.

iv+ The population sample is stable where the death rate and birth

rate are the same.

$. The abiotic factors that affect the population distribution of an

organism are

i+ Temperature

ii+ Light intensity

iii+ Humidity

iv+ pH

v+ Aspect


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iodiversity

/+ iodiversity refers to the diverse species of organism on earth.

#+ Since there are many organisms in the world* it is necessary to

classify them. A systematic method of classification :


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Linnaeus binomial system

1ach organism is given a scientific name according to the Linnaeus

inomial System. )n this system* each organism has two names* that is;a+The first name refers to the genus. )t begins with a capital

letter*

;b+The second name refers to the species. )t begins with a

small letter. oth names are written in italics or underlined.

1ample:

Humans homo sapiens

Lion 'anthera leo

urian urio (ibenthinus


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The impact of microorganisms on life

/+ A microorganism is a tiny organism that can only be seen with the

help of a microscope.

#+ !icroorganism can be divided into five groups.

0+ !icroorganisms are* useful in decomposition* nitrogen cycle*alimentary canal of termites and digestive system in humans.

&+ Harmful microorganisms are microorganisms that can cause

diseases* spoilage of food and paint.

$+ !icroorganisms that cause diseases are called pathogens.

6ro0p ofmicroorganism

eat0res

() Bacteria Bnicellular microorganism

Have a cell wall* plasma membrane and 6Athat is not enclosed in a membrane

=eproduce aseually by binary fission


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1ample: phytoplankton* spirogyra*clamydomonas

7) 0ngi Bnicellular microorganism

Heterotrophic* that is* as saprophyte orparasites

Have no chlorophyll* stem *roots or leaves

Have cell walls made of chitin

1ample: yeast

8) Proto3oa Bnicellular organisms

Have a nucleus* cytoplasm and a plasmamembrane* do not have a cell wall

,an carry out processes such as respiration*ecretion and reproduction

Heterotrophic

1amples: paramecium* amoeba* euglena

9) 'ir0s Smallest microorganism that can only beseen under an electron microscope

,onsists of nucleic acid that is ribonucleicacid ;=6A+ or deoyribonucleic acid ;6A+surrounded by a protein layer

'arasitic. 1ists as various forms* that is*spherical* rod-shaped* tadpole shape or othershapes

1amples: bacteriophage* tobacco mosaicvirus


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The use of microorganisms in biotechnology

/+ !icroorganisms are used in production of antibiotics and vaccines.

#+ Sewage from households and industries is channeled into large

settling tanks in sewage treatment plants. uring treatment* the

aerobic bacteria in the sewage will decompose the organic matter.

0+ ioplastic such as iopol is a biodegradable plastic that can be

broken down into inorganic compound by bacteria.

&+ io is a gas produced by the fermentation of organic matter in waste

involving the use of microorganisms in a bioreactor. The biogas

accumulated is collected and used as fuel.

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An Environment Consists Living Organisms and Non