Biology Chapter 1: Introduction

Biology and Its Branches

• Biology is the study of living things, a branch of science that deals with the living part of nature and the non-living things that affect the living things.
• Biologists strive to understand, explain, integrate, and describe the natural world of living things.
• The literal meaning of biology is the study of life, which is difficult to define.
• Biologists deal with the matters relating to how life works, focusing on characteristics that distinguish living organisms from non-living objects.

Branches of Biology

• Ecology: deals with environmental relations
• Embryology: deals with development
• Physiology: deals with functions
• Morphology (or Anatomy): deals with structure, form, and internal gross structure
• Palaeontology: deals with fossil
• Histology: deals with tissues
• Evolution: deals with ancestral history
• Genetics: deals with heredity
• Zoogeography: deals with distribution of animals in nature
• Molecular Biology: deals with the structure of organisms at the molecular level
• Microbiology: deals with the study of microorganisms
• Environmental Biology: deals with the study of organisms in relation to their environment
• Freshwater Biology: deals with the study of organisms living in freshwater bodies
• Marine Biology: deals with the study of life in seas and oceans
• Parasitology: deals with the study of parasites
• Human Biology: deals with the study of man
• Social Biology: deals with the study of social behavior and communal life of human beings
• Biotechnology: deals with the use of living organisms, systems, or processes in manufacturing and service industries

Levels of Biological Organization

• Atomic and Subatomic Levels: all living and nonliving matter is formed of simple units called atoms and subatomic particles
• Molecular Level: elements combine to form compounds, which are then arranged to form molecules
• Organelles and Cell: molecules arrange themselves to form cells and their organelles
• Tissue Level: groups of similar cells are organized into tissues that perform similar functions
• Organ and System: different tissues assemble together to form organs that carry out specific functions

Characteristics of Living Things

• Living organisms are highly organized, complex entities
• They are composed of one or more cells
• They contain a genetic program of their characteristics
• They can acquire and use energy
• They can carry out and control numerous chemical reactions
• They can grow in size
• They can maintain a fairly constant internal environment
• They can respond to changes in their environment
• They can produce offspring similar to themselves### Organization of Living Organisms
• Organs are part of organ systems where total functions involved in one process or phenomenon are carried out
• In animals, organ formation is far more complex and defined
• In plants, organ level of organization is less defined, with roots, stems, leaves, and reproductive structures having clear functions
• Organs are assembled together to form an individual (whole organism), with its own individuality and characteristics

Coordination and Regulation

• In animals, coordination is achieved by means of nervous system and endocrine system
• In plants, only long-term regulation of activities is brought about by hormones
• The whole organism works together and interacts with the environment as a whole

Population and Community

• A population is a group of living organisms of the same species located in the same place at the same time
• Population is a higher level of biological organization than organism (whole), with its own attributes such as gene frequency, gene flow, age distribution, population density, and population pressure
• Communities are dynamic collections of organisms, in which one population may increase and others may decrease due to fluctuations in abiotic factors

Ecosystems and Biomes

• Biomes are large regional communities primarily determined by climate
• Distribution of organisms in space can be studied through biomes
• The type of plant determines the other kinds of plants and animals in a biome

Fossil Record and Evolutionary History

• Fossils allow biologists to place organisms in a time sequence
• The fossil record shows the temporal distribution of various forms of life in different geological periods
• Phyletic lineage is an unbroken series of species arranged in ancestor to descendant sequence

Biological Method

• Biological sciences have a systematic methodology based on experimental inquiry

• Observations can be qualitative or quantitative, and are organized into data to form a hypothesis

• Deductive and inductive reasoning are used to formulate hypotheses

• Hypotheses are tested and repeated exposure to possible falsification increases confidence in the hypothesis

• A well-supported hypothesis is used as the basis for formulating further hypotheses, leading to a theory### Biology and Its Significance

• Biology is the study of living organisms and their interactions with the environment.

• The science of biology has contributed significantly to increasing food production, combating diseases, and protecting the environment.

Advancements in Food Production

• Plant breeders have developed new high-yield and disease-resistant varieties of plants and animals using selective breeding and genetic engineering.
• Transgenic plants with desirable characters can be propagated using tissue culture techniques.
• Biological control methods, such as using living organisms to control pests, eliminate toxicity problems and environmental pollution.
• Integrated disease management involves using multiple methods to control diseases.

Disease Control

• Three pronged actions are taken against diseases: preventive measures, vaccination/immunization, and drug treatment/gene therapy.
• Preventive measures involve taking precautions to avoid contracting diseases, such as avoiding free sexual contact and blood transfusions.
• Vaccination/immunization involves making people immune to viral or bacterial epidemics through inoculation.
• Drug treatment involves using antibiotics to kill bacteria, and chemotherapy and radiotherapy to treat cancer.

Gene Therapy

• Gene therapy involves repairing defective genes by inserting normal genes into the host through bone marrow cells.
• Integrated disease management involves community participation and awareness about disease severity, causes, and remedies.

Cloning

• Cloning is a technology for achieving eugenic aims, producing genetically identical copies of a desired genotype.
• Cloning involves removing the nucleus from a fertilized egg and inserting a nucleus from a fully developed individual.
• Cloning can be used to produce genetically identical cattle and other farm animals.

Protection and Conservation of Environment

• Industrialization has led to environmental pollution, destroying the environment and human health.
• Biologists are working to address this problem by treating industrial effluents and promoting bioremediation.
• Environmental pollution is a national problem in Pakistan, affecting rivers, canals, and freshwater life.
• Protective measures, such as using lead-free petrol, are necessary to reduce pollution.