Theoretical course of

General Zoology

Prepared by
Dr. Masoud Lakhwani Elhassy
 Introduction to Zoology

Biology is branch of Science in which living beings are studied. The

term of biology was first coined by Lamarck and Treviranus in the

year 1801. Biology has two main branches:

● Botany: The Study of different aspects of plants. Theophrastus is

known as father of Botany.

● Zoology: The Study of Various aspects of animals. Aristotle is called

father of Zoology as well as Biology.

Zoology Definition

- Zoology (or animal Biology) may be defined as the body of facts and

doctrines derived from the scientific study of animals.

- In another definition, we can say that Zoology is the field of Biology that

involves the study of animals.

The word zoology comes from the Greek words zōion, meaning

“animal”, and logos, meaning “the study of”. It encompasses all aspects

of scientific knowledge about animals, like embryonic development,

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evolution, behavior, ecological distribution, and classification. Zoology is

broken into many branches because there are so many different ways to

study animals; it is also broken into branches based on which animals are

being studied.

History of Zoology

People have been interested in learning about animals since ancient times.

The prominent ancient Greek philosopher Aristotle took detailed notes on

animal observations, and inspired other scientists for many hundreds of

years. Many Universities were founded in Europe in the 16 th Century, and

by the mid-17th Century, divisions were founded in Universities that

focused entirely on animal research.

In the 19th Century, the microscope became commonplace in scientific

research, and this opened up a whole new realm of possibility; now, the

cells of animals could be studied at the microscopic level. Another

breakthrough in zoology occurred when the naturalist Charles Darwin

developed the theory of evolution by natural selection. This theory

revolutionized zoology and taxonomy (classification). More recently, the

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discovery of DNA as life’s genetic material led to even more new research

and knowledge about the natural world and the evolutionary relationships

between animals.

Branches of Zoology

The detailed investigation of animals has led to the establishment of a

number of subsidiary zoological sciences, such as the following:

- Systematic Zoology: the science that is concerned with the description

of animal species and their arrangement according to a logical plan of

classification.

- Animal Morphology: is the science of form and structure.

- Anatomy: is the science that pertains to the gross dissection of organs.

- Histology: is the science that is concerned with the microscopic study

of tissues.

- Embryology: is the science that is concerned with the development of

animals, organs, and tissues.

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- Animal Physiology: is the science that is concerned with the study of

functions of the parts of animals.

Animal physiology is the study of the bodily processes that occur in

animals that allow them to maintain homeostasis and survive.

Homeostasis is the ability of the body to maintain a relatively constant

equilibrium even in a changing environment. One example is the

regulation of body temperature in mammals. Humans have a normal body

temperature of about 37°C (98.6°F), even when the environment they are

in is much colder. Animal physiology involves the study of processes like

temperature regulation, blood pressure and blood flow, and the release of

hormones at specific times in the body.

- Animal Ecology: is the study of the relationships of animals to one

another and to their environment.

- Ethology: is the study of animal behavior, usually in regard to in their

natural environment as opposed to in a lab.

Ethology has roots in the work of Darwin, but emerged as a field in the

1930s. It involves the study of animal learning, cognition,

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communication, and sexuality, and is related to evolutionary Biology and

ecology. Principles from ethology research are also used in animal

training.

- Behavioral Ecology

Behavioral ecology emerged from ethology. It is the study of evolution as

the basis for animal behavior due to ecological pressures, which are

constraints placed upon organisms by their environment.

Organisms with traits that are well-suited to their environment have a

higher likelihood of surviving and reproducing than those that do not.

When the proportion of individuals with favored traits increases over a

long period of time, evolution can occur. Behavioral ecologists study

animals’ competition for resources such as food, territory, and mates and

the increased reproductive success that certain traits may give.

- Evolutionary Zoology: is the science that is concerned with the origin

and descent of different species of animals.

- Paleozoology: is the science that studies the fossil remains of animals.

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Groupings by Animal

Zoology is also broken down into subcategories based on the type of

animal being studied. For example, a distinction is made between

invertebrate zoology and vertebrate zoology. There are also many specific

terms for each type of animal that is studied. Some examples are:

- Mammalogy: is the study of mammals.

- Ornithology: is the study of birds.

- Herpetology: is the study of amphibians and reptiles.

- Ichthyology: is the study of fish.

- Entomology: is the study of insects.

Entomology is itself broken down into many categories because there are

so many types of insects. Some examples of its subcategories are

Lepidopterology, the study of butterflies and moths, Myrmecology, the

study of ants, and Coleopterology, the study of beetles.