WASSCE Introduction to Biology Lecture slides (Part 1)

WASSCE Introduction to Biology Lecture Slides Lecture 1. (Part 1 of 3) Designed for West African Students. First Topic in the Elective Biology Textbook

1. INTRODUCTION
TO BIOLOGY
LECTURE 1
WASSCE BIOLOGY

2. Explain the term biology
List some of the branches/fields of biology
Describe the methods of science used to solve
problems
Explain the term Body Symmetry
Distinguish between the types of sectioning in biology
Apply the rules of biological drawings
Objectives

3. What is Biology?
Biology is the study of the form and function of living
organisms, and how they interact with each other and the
environment
It examines the structure, function, growth origin, evolution,
and distribution of living things.
It is often called the science of life

4. Living
Things
Living things
Eat
Move
Breathe
Have offspring
Excrete
React
Grow
These are called life
processes E.g, Cats, Dogs, Fish
Non-
Living
Things
Do not perform any life processes.
E.g Bricks, Stones, Wood

5. Life Processes
They are
Life Processes are the seven basic characteristics
that distinguish living things from non-living things
Nutrition1.
Respiration2.
Movement3.
Excretion4.
5. Reproduction
6. Sensitivity/ Irritability
7. Growth

6. Nutrition
The process by which living organisms
make or obtain food and utilize it for
growth maintenance.
Food is the material from which organisms
obtain the energy required to sustain life
through respiration and carry out all the
other processes of life.

7. Types of Nutrition
Autotrophic: living organisms synthesize
or manufacture their food using simple
inorganic substances from nature. E.g,
plants photosynthesizing
Heterotrophic: Organisms obtain their
food from other living organisms. E.g lion
eating a zebra, A giraffe eating plants

8. Photosynthetic: These are organisms that make
their own food using energy from sunlight.
E.g., green plants.
Chemosynthetic: These are organisms that make
food using energy from inorganic chemicals.
E.g., sulphur bacteria (Thiobacteria). Sulphur
bacteria use hydrogen sulphide to synthesize
organic food.
Autotrophic Nutrition

9. Heterotrophic Nutrition
Holozoic Nutrition: Living organisms take in solid, already-made
food
E.g, a monkey eating a banana
Saprophytic Nutrition: The living organism feeds on dead organic
material. Saprophytes such as fungi and some bacteria, release
enzymes to digest their food outside and then absorb the digested
food.
Parasitic Nutrition: The living organism (the parasite) depends on
another living organism (called the host) for its food. E.g., tapeworms
and ticks.

10. Holozoic Nutrition
Carnivores: Organisms that feed on the flesh
of other animals. E.g., dogs, sharks and lions
Herbivores: Organisms that feed directly on
plants. E.g., cattle, goats and grasshoppers
Omnivores: Organisms that feed on both
plants and animals. E.g., human beings

11. Autotrophic
Found in Plants
Involves the intake of
simple substances
Manufacture their own
food
Requires sunlight
Involves an anabolic
process
Heterotrophic
Found in animals
Involves intake of complex
substances
Does not manufacture
their own food
Does not require sunlight
Involves a catabolic
process

12. Respiration
Respiration is a sum total of chemical reactions which
result in the breakdown of food substance to release
energy with or without the use of oxygen.
Involves gaseous exchange
External respiration (breathing )
Internal Respiration (Cellular Respiration)
Kinds of respiration

13. Types of celular respiration
Aerobic Respiration (With Oxygen)
This is the breakdown of glucose in living cells to provide
energy in the presence of oxygen. The by-products of the
reaction are water and carbon dioxide.
Anaerobic Respiration (Without Oxygen)
This occurs when glucose is broken down to release energy in
absence oxygen. In humans, muscle cells respire anaerobically
and the by-product is lactic acid. Plant and yeast cells respire
anaerobically, producing carbon dioxide and alcohol as a by-
product.

14. Formulas for Respiration

15. Movement
Movement is the change in position of the whole body or
parts of the body, from one place to another, in search for
food, shelter, mates, etc
Locomotion is to move the whole body of an organisms to
a different place. Movement is the change in position of
parts of the body

16. Excretion
Excretion is the removal of waste metabolic
products from the body. Waste products such as
carbon dioxide, ammonia, urea etc. are poisonous
and slows down vital chemical reactions, if allowed to
accumulate.

17. Reproduction
Reproduction is the process by which living organisms give
rise to new individuals of their own kind. This ensures the
continual existence of the species of an organism.
There are two main kinds of respiration: Sexual and
Asexual Reproduction

18. Adequate Reproduction
Asexual reproduction involves only one plant or
individual to produce a new organism. The
process involves no fertilization or exchange of
genetic material. Offspring are identical to the
parent. E.g., plants such as potatoes or onion,
grow from tubers or bulbs.

19. Sexual Reproduction
Forms of Sexual Reproduction
Sexual reproduction involves the fusion of male and female
gametes or sex cells to form single cell called a zygote, which
develop into new organism. The offspring display some
characteristics of both parents. Sexual reproduction ensures high
degree of variation among organisms.
Conjugation: involves gametes of similar shape and size
Fertilization: involves gametes of different mating types.

20. Types of Fertilization
Reproduction in which fertilization takes place
outside the parent’s body. E.g. frogs
Reproduction in which fertilization takes place inside
the parent’s body. This type fertilization necessary
for organisms that produce smaller number of sex
cells. E.g birds
External Fertilization
Internal Fertilization

21. Advantages of Internal
Fertilization
Disadvantages of External
Fertilization
No chance of fertilized eggs being
eaten by predators
Embryo is protected from shock by
the amniotic fluid
Zygote obtain oxygen or nutrients
from the mother
Fertilized eggs are protected inside
the parent from harsh environmental
condition like temperature
Excretory products of embryo are
removed by mother’s circulation
Chance of fertilization is high
Not stationary: Move around as
they will
No cellulose cell wall present
Heterotrophic mode of
nutrition
Chlorophyll not present
Cannot undergo
photosynthesis
Reserves food in the form of
glycogen

22. Key Vocabulary
The ability of living organisms to struggle for all necessity of life to
survive in their environment.
Competition
Adaption
The ability of organisms to adjust to changes in environment for
survival.
Life Span
The period of existence of an organism

23. Sensitivity/Irritability
It is the process by which living things respond to stimuli
(singular: stimulus). A stimulus is any environmental factor that
triggers an action. Examples of stimulus are sound, heat,
touch chemicals, taste, smell, temperature, nutrients, water
level etc. Living things are sensitive to changes in their internal
and external environment. This means that they detect and
respond to events in order to maintain a stable and a healthy
environment.

24. Growth
Growth is irreversible or permanent increase in measurable
features such as size, weight and length of an organism.
Most animals grow until they reach maturity and then
remain at a constant size while plants usually continue to
increase in size throughout their life span. Cells increase in
number by dividing in a process called mitosis.

25. Plants Animals
Stationary: Do not move
around
Presence of cellulose cell wall
Autotrophic mode of nutrition
Prescence of chlorophyll
Undergo photosynthesis
(prepares their own food)
Reserves food in the form of
starch
Not stationary: Move around as
they will
No cellulose cell wall present
Heterotrophic mode of
nutrition
Chlorophyll not present
Cannot undergo
photosynthesis
Reserves food in the form of
glycogen

26. Branches of Biology
Botany: the study of plants
Zoology: the study of animals
Microbiology: the study of
microscopic organisms
(microorganisms) and their
interactions with other living things
Virology: the study of viruses
Bacteriology: the study of
bacteria
Mycology: the study of fungi
Parasitology: the study of
parasites and parasitism
Physiology: the study of functions of
organs and parts of living organisms
Genetics: the study of genes and
heredity
Histology: the study of cells and tissues
Anatomy: the study of form and function
in plants, animals, and other organisms
Entomology: the study of insects etc.
Embryology: the study of the
development of the embryo of an
organism.
Ecology: is the study of plants and
animals in relation with their environment

27. Importance of Biology
It helps us to know and appreciate the complexity of living processes.
It helps to understand how diseases affect the body and ways to
control disease.
It helps maintain a healthy ecology for humans, animals, and plants.
It enables the use of forensics to trace and arrest errant members of
society.
It allows agriculturalists to rear unique and specific breeds of plants and
animals.
It helps in creating solutions to the challenges many living organisms
face.
It paves the way for inventions and discoveries that improve quality of
life.

28. Thank
You
MOATAPARI
AGBERE @WA.VIRTUAL
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