Posted by Chester Morton / Saturday, 14 May 2016 / No comments
Introduction to Science - Biology
After
going through this chapter, the student should have an in-depth knowledge on
the subject.
Distinguish
between fundamental units and derived units
Understand
the basic components of each of the four areas under the subject
WHAT IS SCIENCE?
Science is defined as the knowledge acquired through
systematic observation, experimentation and evaluation of information gained in
relation with other bodies of knowledge.
INTRODUCTION TO BIOLOGY
Biology is the scientific study of living things and their
relationship with the environment. The environment is made up of living and
non-living things.
Non- living things are the things that do not have life in
them. Thus they cannot carry out life processes, example, stone, book,
television, among others.
Living things on the other hand are things that have life in
them and can carry out life processes. Living things are made up of plants and
animals, example, human being, fishes, timber, among others.
WHAT ARE LIFE PROCESSES?
They are characteristic processes that all living organisms
carry out. Life processes of living things include the following
MOVEMENT/LOCOMOTION
REPRODUCTION
NUTRITION
EXCRETION
RESPIRATION
GROWTH
SENSITIVITY
MOVEMENT/LOCOMOTION: This may include the whole organism
moving from one place to another (locomotion). Plants do not loco mote, however
their parts example, root move from one place to another.
RESPIRATION
It is defined as the chemical process through
which food substances are broken down within the cell of an organism to release
energy with or without the use of oxygen. Respiration occurs in two forms; that
is exchange of gases or internal respiration.
Respiration
that takes place in the presence of oxygen is known as AEROBIC RESPIRATION
while the respiration that occur in the absent of oxygen is called ANAEROBIC
RESPIRATION.
NUTRITION
It is the process by which living things obtain
and use food. Nutrition provides the energy needed by an organism to carry out
other life processes. Animals and plants under go this process of feeding in
different ways. Plants take theirs by a process known as PHOTOSYNTHESIS while
animals eat PLANTS AND
OTHER ANIMALS.
EXCRETION
It is the process whereby metabolic wastes are
removed from the body of living organism. Metabolic wastes are poisonous,
harmful, useless substances which when accumulated within the cell or an
organism causes other malfunctioning and diseases.
REPRODUCTION
It is the process by which living things give
rise to new individuals of their own kinds. Reproduction is very important
because it present organism from extension. There are two types of respiration,
SEXUAL AND ASEXUAL RESPIRATION.
GROWTH
This is the ability of an organism to increase in
size or weight due to increase in the cytoplasm of the cell. Growth brings
changes to the body either in shape or size.
SENSITIVITY/ IRRITABILITY
This is the ability of an
organism to respond to stimulus (changes in the environment). Stimulation can
be favourable or unfavourable.
BIOLOGICAL CLASSIFICATION
Classification refers to the sorting out of living things
and putting them into groups, based on certain features.
REASON
FOR CLASSIFICATION
Easy
identification
To
enhance research
To
place a rank in organism
Permit
description of organisms using one or few words
Forms a
common pool of knowledge
Permits
new organisms to be identified and classified
HISTORY OF
CLASSIFICATION
Aristotle a Greek (382-322) classifies organisms based on
their ability and inability to fly. But in 1707, Carolous Linnaeas (1707-1778)
did not agree to this rather, he classify organism based on SEVEN (7) RANKS as
KINGDOM→PHYLUM/DIVISION→CLASS∩→ ORDER→ FAMILY→ GENUS→SPECIES
(KING PHAROH CALLS ORDER FOR GENERAL SCIENCE)
We will now focus on the KINGDOM classification of
organisms.
KINGDOM ORGANISM:
All organisms are put under five (5) kingdoms. These are:
KINGDOM
ANIMALIA: The members in this group include man, fish, monkeys, birds, insects,
toads, among others.
Characteristics:
They
have nucleus enclosed by nuclear membranes
They
have no cell walls
They
are multi-cellular
They
rely on external sources for food
They
reproduce by the fusion of the male and female gametes.
KINGDOM
PLANTAE: Members of this group have chlorophyll and include mango, maize,
mosses, ferns, flowers, among others.
Characteristics:
They
are multi-cellular
They
have chlorophyll to manufacture their own food
They
have cell walls made up of cellos
They
have nucleus enclosed by nuclear membranes
KINGDOM
PROKARYOTAE / MONERA: They include bacteria and blue-green algae
Characteristic:
They
are microscopic
They
are unicellular
They
have no definite nucleus
They
have no membrane bound organelles
KINGDOM
PROTOCTISTA/ PROTISTA: They include protozoa, paramecium, plasmodium,
trypanosome, green algae, etc.
Characteristics:
Many of
them are unicellular although a few are multi-cellular
They
have normal cell organelles but no tissues
They
have nucleus
KINGDOM
FUNGI: They include mushroom, moulds, parasitic fungi, ringworm, etc.
Characteristics:
They
are non-mobile multi-cellular
They
have no chlorophyll
They
have no stems, roots or branches
They
have cell walls but it made of chitin.
BINOMIAL SYSTEM OF NAMING ORGANISM
This involves the use of the Genus and Species to give
organisms two names known as SCIENTIFIC NAMES in animals and BOTANICAL NAMES
in plants. The scientific name for man is Homo-Sapien and the botanical name of
maize is ZeaMays.
VIRUSES
Viruses do not fall under any of the ranking above. Viruses
are very tiny organism and cannot be seen under light microscope except an
electric microscope.
Characteristics:
They
are made up of Deoxyribonucleic acid (DNA)
They
have no nucleus, cytoplasm or cell membrane
They
are not cells but particles
They
are capable of producing a new generation of viruses when in living organisms
They
cannot grow unless attached to living cells
