The Study of Living Things

Introduction to Biology

•

Biology,

the study of living things, has fascinated mankind since the Creation. • The word comes from the Greek root

bios,

which means “life,” and the Greek suffix

-logy,

which means “science of’ or “study of.” • As you think about living things, your mind may picture the larger scope of life such as a pond or a forest, each area thriving with many different plants and animals. • As you step outside in your thoughts into the world of nature, you may visualize a field with numerous kinds of plants and small animals, a mountain stream flowing among the trees, or the ocean with its vast number of creatures. • This is where man began to study biology.

• Adam and Eve were given the responsibility by God to subdue the earth and use it for their benefit. From the beginning, man has been naming, using, and studying living things.

• This course of study will give you the unique opportunity to learn about the living world in the sequence in which scientists have learned of it.

• You will study many of the organisms (living things) which God has created, often in their natural habitats (regions where particular organisms normally live). Your study will involve field observations, reading, use of the microscope, and dissection of organisms. • You will learn many things about how your own body works, and your study will conclude with a detailed look at the intricate workings of living cells.

Major Fields of Biology

• Traditionally, people have divided the earth’s living things into three major groups —plants, animals, and people. These groups correspond to three major fields of biology • botany, the study of plants; • zoology, the study of animals; and • human anatomy and physiology [fiz i.öl’ôji] the study of the physical structure and function of the human body.

• Your study of biology will acquaint you with many aspects of the variety and design of the living creation. • As you become more familiar with many organisms living close to you, you will come to realize how important they are to nature and to you. • One of the most obvious truths that your study will reveal is the design used by God throughout all of life on earth and how all of nature fits together according to plan.

• Your study of creation should lead you to a deeper understanding of the Creator. GOD

• For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead,’ so that they are without excuse. Rom.1:20 • John 1:1-3 1In the beginning was the Word, and the Word was with God, and the Word was God. • 2He was with God in the beginning. • 3Through him all things were made; without him nothing was made that has been made.

• • • • Man’s role in God’s creation is explained in Genesis 1:28.

And God blessed them, and God said unto them, Be fruitful, and multiply, and replenish the earth, and subdue it: and have dominion over the fish of the sea, and over the fowl of the air, and over every living thing that moveth upon the earth.

God instructed man to become the master of His creation.

The Crown of God’s Creation

• • • The human body is a veritable museum of science, full of God’s creation wonders.

Alfred M. Rehwinkel Man is the most magnificent part of God’s creation —far more complex in structure and design than the earth or any heavenly body.

•

Each of his body’s 100 trillion cells is an enormously complex assembly of compartments, girders, factories, motors, sensors, and control systems; together, they contain roughly 60 billion miles of DNA representing 70 trillion gigabytes of information.

•

Pound for pound, his intricately constructed, self-healing bones are as strong as reinforced concrete and much more resilient.

• With training, his muscles allow him to lift several times his own weight, sprint at nearly 40 feet per second, leap with the grace and agility of a gymnast, or push on for hour after hour in a grueling marathon.

• Yet his muscles are also capable of such precision that his hands can assemble a Swiss watch or repair a damaged eye.

• A man’s heart is an efficient four-chambered pump that beats, on average, a hundred thousand times per day, pumping blood through 60,000 miles of blood vessels to distribute food and oxygen throughout his body. • The red blood cells that transport oxygen through this vast network are manufactured at a rate of 2.4 million

per second.

• The oxygen the blood carries is supplied by 600 million gas-exchange chambers in his lungs, which have a total surface area the size of a volleyball court.

• His intricately designed, auto focusing eyes provide him with extraordinarily high resolution images of the world around him, from objects a few inches distant to giant galaxies a billion billion miles away; • they can adjust from the silvery outlines of a moonlit landscape to the million fold greater brightness of a sunny day. • Unequalled image processing equipment in his optic nerves and brain allow both rapid object recognition and the ability to almost intuitively analyze angles and speeds.

• His delicately crafted ears can detect the faint rustling of distant leaves, yet allow him to analyze sounds that are ten billion times more intense. • His sense of smell enables him to detect and distinguish ten thousand different chemicals, • often in amounts so vanishingly small that they would have been difficult to detect by any other means until the twentieth century.

• All of this marvelous assembly is controlled and coordinated by the brain, a three-pound, ten-watt supercomputer that contains more than 100 quadrillion electrochemical connections. • Not only is the human body the crowning glory of God’s creation; it is superior to the best machines that modern technology can build.

• The intricate workings of the human body point to God’s wisdom in creation and cause us to exclaim with the Psalmist: • I

will praise thee; for lam fearfully and wonderfully made: marvellous are thy works; and that my soul knoweth right well.

Ps. 139:14

The Role of Scripture in Scientific Investigation

•

1. Source of truth.

The Scriptures give us the truth about God and about man’s relationship to God and also provide us with a true account of the origin of all things. • In addition,

God’s Word furnishes us with an interpretative framework

by which to view life and the world.

• Basic to this framework are the three Biblical presuppositions without which science would be impossible: 1. There is an order in creation.

2. There is a cause, or reasonable explanation, for every effect, or event, in creation.

3. There is something real to be discovered and understood about creation.

• It should be kept in mind, however, that although God has chosen to reveal some important scientific truths to man through • His Word (such as the facts of creation and the principle of entropy), He has apparently not chosen to reveal the

details

of most day-to-day processes (such as photosynthesis, the motions of the planets, and the structure of the earth). • Rather, these subjects He has left to mankind to investigate under the mandate of Genesis 1:28.

Nature is Knowable

• All scientists, Christian or non-Christian, must accept these postulates in order to do scientific work of any kind. • They must also assume that there is a correlation between the human mind and the external world, that nature can be truly known and understood by human minds.

• However, these presuppositions are rather difficult to justify apart from the Biblical worldview.

• Without the restoration of the authority of God’s Word brought about by the Protestant Reformation, modern science and technology may not have arisen. • Without the open book of Scripture, there is no open book of nature .

• Sir Francis Bacon, devout Protestant philosopher, essayist, statesman, and formulator of the scientific method, declared: • Let no man.. , think or maintain that a man can search too far or be too well studied in the book of God’s Word, or in the book of God’s works; divinity or philosophy; but rather let men endeavor an endless progress or proficiency in both.

Solving Scientific Problems

• The biologist faces many problems. • These are some of the many difficult problems which face biologists and other scientists, who often employ a special problem solving process known as the

scientific method

(also called the research

method)

to solve scientific problems.

• Scientific research and investigation, when not conducted in areas forbidden by God’s law or hostile to the doctrinal or ethical content of God’s Word, are a valid part of man’s task to subdue the creation and exercise dominion over it under God.

Steps in the Scientific Method

1. State the problem clearly and completely.

2. Examine the available facts and suggest as many probable solutions (hypotheses) as possible.

3. Test every hypothesis; modify or reject faulty ones.

•

4. Form a conclusion that is based upon all known facts, causes, and effects.

•

5. If the facts are not sufficient to justify forming a conclusion, keep an open mind toward the problem until enough is known to justify a conclusion.

•

6. Test the conclusion with additional controlled experiments.

The variety of living organisms

AIMS

• understand why there exists a range of living organisms on Earth; • list and define the characteristics of life; • describe the major groups of organisms • understand how a classification system is used to group all living organisms; • observe and classify living organisms according to visible similarities and differences; • understand the meaning of the term ‘species’.

• The planet Earth, the third planet from the Sun, has all the conditions necessary to support life as we know it. • Our planet is positioned at such a distance from the Sun that living organisms can survive in the range of temperatures on its surface (although it is a fairly wide range). • The presence of water in all its forms (solid, liquid and gas), and the combination of gases which make up the atmosphere (including nitrogen, oxygen and carbon dioxide), are all conditions that are essential to life on Earth.

SPOT TEST • List three characteristics of the planet Earth that enables it to sustain life?

• A huge variety of living forms exist on the planet Earth. • They can inhabit most of the Earth’s surface; land, air and water. They show an enormous range in size and complexity from the microscopic, • which cannot be seen by the naked eye and are as simple as one cell, to giant-like whales which must live in water since they are too heavy to support themselves and move on land.

Characteristics of life

• Biology is the study of life and how living things stay alive. • All living organisms, microscopic to gigantic, possess certain characteristics • These are the characteristics of life that distinguish living things from non-living things. • There are seven of these characteristics:

Characteristics of life

1 Growth

— Living organisms increase in mass, size and numbers.

2 Respiration

— The energy released during respiration is needed to carry out all life processes.

3 Irritability

— Living organisms can respond to changes in their internal environment and the world around them. These responses usually increase their chances of survival.

Characteristics of life

4 Movement

— Most living organisms can move. Plants show growth movements. Most animals can move from place to place to find food or a mate.

5 Nutrition

— All living organisms need food which is used as a source of energy. Plants make their food during photosynthesis. Animals get their food by eating plants or other animals.

6 Excretion

— All living things make waste products during metabolism. These must be removed from the body.

7

Reproduction

— This is the production of new organisms.

Quizz

• Animals and plants are able to carry out certain processes which distinguish them from non-living things. Describe briefly how a plant (I) feeds, (ii) responds.

The major groups of organisms

• All organisms used to be classified or placed in two kingdoms or main groups animals and plants, depending on whether they get their food from other organisms or make their own food. • However, living things are more diverse than this and a classification system of five kingdoms is now used.

Kingdoms

• These kingdoms are the Prokaryotes, Protoctists, Fungi, Plants and Animals.

Viruses

• Viruses do not fit into this classification. They are the smallest organisms, though it is difficult to think of them as living because they can only ‘live’ inside another living cell. They also do not have a true cellular structure like other organisms.

• Billions of viruses ‘exist’ around us and it is only when they enter the cells of an organism that they show some of the characteristics of life.

• There they can reproduce and grow in numbers.

• Viruses have a great impact on life on Earth, since they can live inside every type of living organism, from bacteria to plants and animals. • It is believed that they have changed the course of human history because of diseases like smallpox, measles and now AIDS.

Quizz

• What are the five major groups of life forms or organisms?

• Prokaryota; • Eukaryota; • Protoctista; • Fungi; • Plantae; • Animalia.

Prokaryotes

• The prokaryotes are organisms that are commonly called bacteria. • They occupy many environments such as soil, dust, water, air, in or on animals and plants. • Some are found in hot springs where temperatures may be higher than 78 °C. Some can survive freezing in ice. Some have been found in deep cracks in the ocean floor, at very high pressures and temperatures of 360 world.

°C.

• They can be found in every part of the living

• They are the smallest organisms that have a cellular structure. • Many exist as single cells, others are found in groups • Their cells have a much simpler structure than those of the eukaryotes • Prokaryotes are vital to all other organisms since they cause decay of dead plant and animal material which releases nutrients back into the environment.

• They are essential to the nitrogen cycle. They are also important to humans because they cause disease (such as cholera and TB chapter) and are used in biotechnology (for example in insulin production

Quiz • Bacteria are described as being microscopic and unicellular organisms. What do these terms mean?

Protoctists

• Most protoctists are unicellular, that is made of one cell. This cell shows all the characteristics of life.

• Algae and protozoa are two kinds of protoctists.

Protoctists (Algae)

• Algae live in both marine and fresh water, and some live on land where the surface is damp. • They make their own food by photosynthesis. Some live as single cells, others are found in groups or colonies.

• A few, such as the seaweeds, can grow extremely large. • These have structures like stems, roots and leaves, but they are much simpler than true plants.

• Rapid growth (blooms) of algae can form scums on the surface of ponds, lakes and rivers, turning them green.

• Red algae causes red tide

Quiz • Using one named example of each, describe one similarity and one difference between algae and protozoans.

Protoctists

(Protozoa)

•

Protozoa

are unicellular and feed on other organisms (heterotrophically). • They are found in all environments, especially in water, and examples include

Amoeba

and

Paramecium.

• They are important to humans because diseases such as malaria and sleeping sickness are caused by protozoan parasites.

• Malaria infects millions of people each year and it is estimated that 2.7 million people worldwide die from this disease each year.

Fungi

• Fungi range in size from unicellular yeasts to large toadstools. • Some are used by humans for medicinal and dietary purposes. • They are heterotrophic organisms and obtain their food from the environment. • However, they do not take in large particles of food that need to be broken down.

• They digest their food outside the body using enzymes which make it soluble. Then they absorb the food.

• So they are usually found living in or on their food, which can be a dead or living organism.

• Fungi reproduce by producing spores asexually or sexually. • These are dispersed by the wind to new environments.

Common fungi are:

• moulds; • yeasts; • mushrooms and toadstools.

Importance of fungi to Man

• Important in the making of the antibiotic penicillin.

• Essential to many fermentation processes, such as making of bread, wine, beer and other alcoholic beverages.

• Used to make a range of chemical products, such as anaesthetics, birth control pills and meat tenderiser.

• Moulds and rusts are fungi that are important in damaging growing crops.

• Cause of spoilage of food.

• Used to make food, such as sufu of East Asia.

Plants (Plantae )

• The plant kingdom includes mosses, liverworts, ferns, conifers and flowering plants. • Almost all plants are photosynthetic.

• • Some plants can be used as medicines.

Bidens

flower. is a weed which has a small daisy-like • The leaves and flowers are steeped and used to ‘cool the blood’ (prickly heat) and to relieve a sick stomach.

• Sometimes it is given to children to cure worms.

Flowering plants

• The flowering plants have true flowers and so make seeds. • They are also called angiosperms and are divided into two groups: • the monocotyledons; • the dicotyledons.

Table shows the distinguishing features of monocotyledons and dicotyledons

Angiosperms

• Angiosperms are the largest group of plants. • They include most crop plants, ornamental plants and plants used as herbs or medicinal plants. • They vary in size from the very small to gigantic (over 90m tall). • They can live in a wide variety of habitats, from deserts to rain-forests.

Animals (Animalia)

• The animal kingdom contains multicellular, heterotrophic organisms. • They are grouped into six phyla:

1. Arthropods (Arthropoda) 2. Molluscs (Mollusca) 3. Chordates (Chordata) 4. Annelida 5. Platyhelminthes 6. Cnidara

Arthropods (Arthropoda)

• Arthropods dominate life on Earth. • They include the

crustaceans, millipedes

,

centipedes, arachnids

and

insects.

• • They all have an exoskeleton (outer

skeleton of

chitin) and jointed limbs.

The crustaceans are aquatic or live in damp places

.

• • • They include woodlice, crayfish, crabs, lobsters and barnacles.

The arachnids include spiders, scorpions, mites and ticks.

They have four pairs of walking legs and are mainly terrestrial and carnivorous.

•

The insects have a distinct head, thorax and abdomen, and three pairs of walking legs.

• They include locusts, bees, ants, beetles, aphids and fleas.

Molluscs (Mollusca)

• The molluscs have a soft body which is often covered by a shell. • They include conch, snails, slugs, cockles, mussels, octopus, squid, clams and oysters.

• Some molluscs like conch and oysters are important to Caribbean people as a source of food and an exotic treat to locals and tourists.

• Farming of molluscs is practiced on some islands as demand exceeds supply from wild populations. • These animals are a renewable resource but populations can decline rapidly because of over-harvesting from their natural habitat.

Chordates (Chordata)

• Most chordates are also vertebrates because they have a vertebral column. • The vertebrates include the fishes (cartilaginous and bony), amphibians, reptiles, birds and mammals.

Birds

(Ayes)

•

wings • skin covered with feathers • produce eggs (reproduction) • are warm-blooded.

Mammals

(Mammalia)

•

four limbs; • skin covered with hair; • most give birth to live young; • feed their young with milk made by the mother (suckle); • are warm-blooded.

Quiz

• Name the five groups of vertebrates, giving two examples of each.

Classification of organisms on the basis of visible characteristics

• The simplest way to classify organisms is according to similarities in their visible characteristics. • For example, if we see a number of organisms, we could start to group them by putting those with wings together. • We can make another group of those with eight legs. We could also put the hairy ones together. And so on.

• However, where do we put those that are both hairy and winged?

• There are two types of classification, artificial and natural. • Artificial classification is based on easily observed characteristics, like colour,shape or number of legs. • This is a convenient and easy method of grouping organisms and is designed for a practical purpose. • However, worms and snakes have the same shape, but snakes have a backbone while worms do not.

• Natural classification tries to use natural relationships between organisms using both internal and external characteristics.

• For example, organisms with backbones are grouped together because they all have backbones and many other similarities. • Similarities in anatomy, physiology and behaviour may all be considered when grouping organisms in a natural classification

Classify these organisms according to similarities in their visible characteristics into three groups.

The Binomial system

• Carl Linnaeus was a scientist in the eighteenth century who first grouped organisms together by a natural classification. • Many people had tried grouping organisms before, but they had all used artificial classifications. • Linnaeus’ classification made it easier to study organisms, since the enormous variety is organised into closely related groups.

• Carl Linnaeus also put forward a system for naming each species of organism • with a biological name, which is called the binomial system. • He did this because organisms may have many common names.

• For example the plant called shadow benny, bandania and calantro in Trinidad and Tobago is called sit weed or spirit weed in Jamaica, and in Martinique and Guadeloupe is known as bandanie.

• Each biological name has two parts which are the same in all these countries and all over the world — the biological name for the plant is

Erynzium soetidum.

• The first word of this name always starts with a capital letter. If you are writing it several times, the first word may be shortened. • For example

Erynzium soetidum

may be abbreviated to

E. soetidum.

• Every known species has a place in this classification. It starts with major groups of general features, which are broken down into smaller and smaller groups that get more and more specific.