Introduction to Biology: Meaning and Scope

The Meaning and Scope of Biology

• Biological sciences involve the study of life and living organisms.
• In Greek, "bio" translates to life, while "logos" means the study of.
• The term biology was coined by Pierre-Antoine de Monet and Jean-Baptiste de Lamarck in the late 1700s.
• The initial study was restricted to botany and zoology which evolved into a broader subject with the development of new technologies.
• The study now includes the minute workings of chemical substances inside living cells to ecosystems and global environmental changes.
• Biological sciences address the physical characteristics and behaviors of organisms from the past and present
• It considers their origins and relationships with each other and their environments.
• Biological sciences also studies the human brain, genes, and reproductive system.
• Biology, also known as life science, is defined as a systematic study of living beings or a study of nature.

The Origin and Nature of Life

• The emergence of life is a significant phenomenon.
• The mystery surrounding life's origins remains a major scientific debate.
• The question of "what is life?" examines the physical reasons a specific material system is an organism.
• Understanding how life may have originated is important.
• The evolution of life has occurred in a series of events.
• The initial living entities were simple, single-celled organisms.
• Multicellular organisms evolved from the single-celled ones by cellular specialization.
• Multi-cellular organism carried out specific tasks.
• Over millions or billions of years organisms changed and evolved to plants and animals

Views on Creation

• Geologists, paleontologists, biologists, and theologians agree on the basic sequence of events in life's evolution.
• Scientists estimate the solar system to be approximately 4.5 billion years old.
• Creationists believe the world was created in six days, basing their beliefs on the Bible.
• Scientists use the scientific method to test hypotheses, develop theories, and create new ideas.

Theories on the Origin of Life

• Theory of Special Creation: All forms of life on Earth were created by a divine being.
• Theory of Spontaneous Generation: Living organisms can arise from non-living matter. Aristotle (384-322 BC) was a supporter.
• Theory of Catastrophism: Multiple creations of life by God, each after a geological catastrophe, and each catastrophe completely destroyed the existing life, and each new creation consisted of life forms different from that of previous ones.
• Cosmozoic Theory (Theory of Panspermia): Life arrived on Earth from other celestial bodies like meteorites in the form of resistant spores. Richter proposed this in 1865, with support from Arrhenius (1908). This theory lacks evidence and was discarded.
• Theory of Chemical Evolution: Life on Earth originated through the gradual chemical evolution approximately 3.8 billion years ago. A.I. Oparin (1923) and J.B.S Haldane (1928) independently proposed this. The theory is also known as materialistic (physico-chemical) theory.

Nature and Characteristics of Life

• Life distinguishes animals and plants from inorganic materials and dead organisms. Life consistists of a process and a maintained state.
• Man is considered the most evolved form of life and has three aspects of life:
• Physical life is basic existence
• Mind provides scope and effectiveness
• Spiritual entity gives maximum living.
• Physiology demonstrates the physical existence of life through the presence of functions.

Living Tissues Exhibition

• Irritability is a capability to detect or be excited and be able to respond to stimuli
• Reproduction and Growth consists of regeneration, duplication, multiplication, and differentiation
• Adaptability permits change and balances maintenance (homeostasis) and also transformation of energy and the use of materials (metabolism)
• Properties can be retained for a while by tissues after death of the organism.
• Excretion and osmoregulation are crucial homeostatic processes inside living cells.
• Excretion removes waste products of metabolism.

Scientific Methods

• The scientific method explores observations and answers questions.
• It's an empirical method to gain knowledge used when constructing/testing a scientific hypothesis.
• The scientific method has five steps, with a feedback loop:
• Observation
• Question
• Hypothesis formation (testable explanation)
• Prediction
• Prediction test
• Iteration: use results to make new predictions/hypotheses

Concepts in the Scientific Method

• Observation is quantitative and qualitative world measurements.
• Inference derives new knowledge from old knowledge.
• Hypotheses are suggested explanations.
• Rejected hypothesis is one that has been ruled out through experimentation
• Accepted hypothesis is one that makes verifiable predictions that are true and has not been ruled out
• Experiments are tests that rule out a hypothesis or validate something already known.
• The scientific method is the process of scientific investigation.
• A theory is an often-tested and widely accepted hypothesis that stands the test of time.

Experimental Testing

• Forming a hypothesis based off of beliefs or expectations, then attempting to find evidence that opposes that that hypothesis. The process establishes what is and is not true.
• The scientific method relies on testing hypotheses through experimentation.
• This involves control subjects not put through the process.
• Scientists attempt to limit variables to one or a minimum number.