Biology: Scientific Approaches and Methods

Biology as a Science

• Biology is the accumulated knowledge about all living things and the principles and laws that govern life.
• A biologist is someone who specializes in biology

Scientific Approaches

• There are two main scientific approaches: Discovery-Based Science and Hypothesis Testing (Scientific Method)

Discovery-Based Science

• This involves the collection and analysis of data without a preconceived hypothesis.
• Information gained may lead to new hypotheses and practical applications.

Hypothesis Testing

• Also known as the Scientific Method.

The Scientific Method

• First defined and documented by England's Sir Francis Bacon (1561-1626)
• Establishes inductive methods for scientific inquiry
• It can be a logical, rational, problem-solving method applied to almost all fields of study.
• It involves recognizing and formulating a problem, collecting data through observation and experiment, and formulating and testing hypotheses.

Steps in the Scientific Method

• Observation is the first step
• Identify the problem by asking testable questions like "what" or "how."
• Formulate a hypothesis in the format "If . . . then . . .", it must also be testable and falsifiable
• Test the hypothesis through controlled experiments
• Analyze gathered data from the experiment
• Generate a conclusion/generalization from the data
• Communicate the result

Variables in Experiments

• Variables are elements that can change during an experiment
• The experimental/independent variable is the factor being tested.
• The responding/dependent variable is the factor measured.
• Controlled variables are factors that remain constant throughout the experiment.

History Of Biology

• The study of life dates back to ancient times, with early people observing animals and plants.

Ancient Period Biology Contributors

• Hippocrates (460-370 B.C.): founded the first medical school on the Greek island of Cos.
• Aristotle (382-322 B.C.): known as the Father of Biology, he developed the first organized study of natural history
• Aristotle was a keen observer, writer, and illustrator of plants and animals.
• Theophrastus (380-287 B.C.): specialized in the organized study of plants and is called the "ancient father of botany."
• Galen (A.D. 130-200): became an unchallenged authority in anatomy.

Renaissance to Modern Ages

• After the Dark Ages (A.D. 200 to 1200), where little to no scientific inquiry occurred, the 14th century brought a revival.

Renaissance to Modern Ages Biology Contributors

• Andreas Vesalius (1514-1564): studied the human body through dissection, challenging Galen's authority.
• Marcello Malpighi (1628-1694): contributed to the science of microscopic anatomy.
• William Harvey (1578-1667): demonstrated the path of blood circulation in the human body.
• Robert Hooke (1635-1703): discovered and named "cells" in cork.
• Anton van Leeuwenhoek (1632-1723): was the first person to see living cells.
• Carl Linnaeus (1707-1778): known as 'The Father of Modern Taxonomy', he devised the system of binomial nomenclature for naming plants and animals.
• George Cuvier (1769-1832): founded the study of comparative anatomy.
• Jean Baptiste Lamarck (1744-1829): came up with the word biology by combining the Greek words "bios," meaning "life," and "logos," meaning "study."

Linnaeus's System of Classification

• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species

Major Fields of Biology

• Botany: study of plants and their life cycles.
• Zoology: study of animals and their life histories.
• Anatomy: study of body structures visible to the naked eye.
• Physiology: study of functions of body organs and systems.
• Embryology: study of embryo development in plants and animals.
• Genetics: study of inheritance and variations in living organisms.
• Evolution: study of origins and relationships among living species.
• Ecology: study of environmental relationships among plants and animals.

Living vs. Non-Living Things

• Living things are alive, made of cells, and perform life functions.
• Non-living things do not possess life

Life Functions of Living Things

• Nutrition: the process by which living organisms obtain food for fuel and growth.
• Transport: involves absorption and distribution of materials within the body.
• Respiration: includes breathing and cellular respiration, where energy is released from nutrient molecules.
• Synthesis: biochemical processes where small molecules are built into larger ones.
• Excretion: removes waste products from the body.
• Regulation: all processes that control and coordinate the activities of living things.
• Growth: increase of cell size and cell numbers.
• Reproduction: the process by which new individuals are produced by parent organisms.

Characteristics of Non-Living Things

• Lifeless and not made up of cells.
• Have a definite and certain size of their own.
• Grow by accretion, adding materials externally.
• Immortal.
• Do not respond to stimuli.

Basic Concepts of Biology

• Metabolism: all chemical activities in the body that produce or use energy.
• Anabolism is the building process where small molecules combine into larger ones, using energy.
• Catabolism breaks apart large molecules, releasing energy.
• Homeostasis: developed by Claude Bernard, refers to the 'steady state' of life functions in an unchanging internal environment.
• Adaptation aids survival in a given environment.
• Adaptations can be structural (e.g., hump of a camel), behavioral (e.g., mating call of a bull frog), or physiological (e.g., controlling tissue cells).