The Science of Biology

• Biology is the science of life
• Properties of life


  • Order
  • Sensitivity
  • Growth, development, and reproduction
  • Regulation
  • Homeostasis
• All living organisms share five basic characteristics: order, sensitivity, growth, development and reproduction, regulation, and homeostasis
• Deductive reasoning


  Applying general principles to predict specific results
• Inductive reasoning


  Using specific observations to construct general scientific principles
• Science is a way of viewing the world that focuses on objective information, putting that information to work to build understanding
• How science is done

  1. Make observations

  2. Develop hypotheses

  3. Conduct experiments to test hypotheses

  4. Make predictions

  5. Establish controls
• Hypothesis


  A suggested explanation that accounts for observations
• Experiment


  A test of a hypothesis
• Control experiment


  An experiment where all variables are kept constant except the one being tested
• A successful scientific hypothesis needs to be valid and useful, making predictions that can be tested experimentally
• Theory


  A proposed explanation for some natural phenomenon, often based on general principles
• This book is organized to help you learn biology, with the first half devoted to general principles that apply to all organisms, and the second half to an examination of particular organisms
• The hypothesis made a clear prediction: that the sun would bend the path of light passing by it. When this prediction was tested in a total eclipse, the light from background stars was indeed bent. Because this result was unknown when the hypothesis was being formulated, it provided strong support for the hypothesis, which was then accepted with more confidence.
• Theory (in science)


  A proposed explanation for some natural phenomenon, often based on some general principle
• Newton's theory of gravity provided a single explanation for objects falling to the ground and the orbits of planets around the sun.
• Theory (in science)


  The body of interconnected concepts, supported by scientific reasoning and experimental evidence, that explains the facts in some area of study
• Quantum theory in physics brings together a set of ideas about the nature of the universe, explains experimental facts, and serves as a guide to further questions and experiments.
• To a scientist, theories are the solid ground of science, that of which we are most certain. In contrast, to the general public, theory implies just the opposite—a lack of knowledge, or a guess.
• The hypothesis that evolution has occurred is an accepted scientific fact; it is supported by overwhelming evidence. Modern evolutionary theory is a complex body of ideas whose importance spreads far beyond explaining evolution; its ramifications permeate all areas of biology, and it provides the conceptual framework that unifies biology as a science.
• Hypothesis


  An educated guess or a hunch, in which the scientist integrates all that he or she knows and allows his or her imagination full play, in an attempt to get a sense of what might be true
• Successful scientists without exception design their experiments with a pretty fair idea of how the results are going to come out. They have what Popper calls an "imaginative preconception" of what the truth might be.
• Basic research is intended to extend the boundaries of what we know. Applied research involves the manufacturing of food additives, creating of new drugs, or testing the quality of the environment.
• The process of careful evaluation, called peer review, lies at the heart of modern science, fostering careful work, precise description, and thoughtful analysis.
• Nonreproducible results are not taken seriously for long.
• The scientific process involves the rejection of hypotheses that are inconsistent with experimental results or observations. Hypotheses that are consistent with available data are conditionally accepted.
• The formulation of the hypothesis often involves creative insight.
• Professor Henslow: 'The absolute want of room is an evil that nothing can surmount.'
• One of the obstacles that had blocked the acceptance of any theory of evolution in Darwin's day was the incorrect notion, widely believed at that time, that the earth was only a few thousand years old
• Evidence discovered during Darwin's time made this assertion seem less and less likely
• Charles Lyell


  A great geologist whose Principles of Geology (1830) Darwin read eagerly as he sailed on the Beagle, outlined for the first time the story of an ancient world of plants and animals in flux
• It was this world that Darwin sought to explain
• When the Beagle set sail, Darwin was fully convinced that species were immutable
• It was not until two or three years after his return that he began to consider seriously the possibility that they could change
• Phenomena Darwin observed that were of central importance to him in reaching his ultimate conclusion

  • Fossils of extinct armadillos similar to the armadillos that still lived in the same area
  • Geographical patterns suggesting organismal lineages change gradually as species migrate from one area to another
  • Giant land tortoises on the Galápagos Islands not all identical, with local residents and sailors able to tell which island a particular tortoise had come from just by looking at its shell
  • Plants and animals on the relatively young volcanic Galápagos Islands resembling those on the nearby coast of South America rather than those of islands with similar climates, such as off the coast of Africa
• The fossils and patterns of life that Darwin observed on the voyage of the Beagle eventually convinced him that evolution had taken place
• Darwin's evidence that evolution occurs

  • Fossils of extinct species most closely resembling living ones in the same area, suggesting one had given rise to the other
  • Progressive changes in characteristics seen in fossils from earlier and earlier rock strata layers
  • Lands with similar climates having unrelated plants and animals, indicating diversity is not entirely influenced by climate and environment
  • Distinctive plants and animals on each continent, with all South American rodents belonging to a single group
  • Oceanic islands having few but often unique (endemic) species showing relatedness to one another, suggesting they developed after their mainland ancestors reached the islands
  • Species on oceanic islands showing strong affinities to those on the nearest mainland
• It is one thing to observe the results of evolution, but quite another to understand how it happens
• Darwin's great achievement lies in his formulation of the hypothesis that evolution occurs because of natural selection
• Geometric progression


  One in which the elements increase by a constant factor