Chapter 1 Introduction: Biology Today Lectures by Chris C. Romero, updated by Edward J. Zalisko PowerPoint Lectures for Campbell Essential Biology, Fourth Edition Eric Simon, Jane Reece, and Jean Dickey Campbell Essential Biology with Physiology, Third Edition Eric Simon, Jane Reece, and Jean Dickey
THE SCOPE OF LIFE The Properties of Life Biology is the scientific study of life. Life is structured on a size scale ranging from the molecular to the global. Biology s scope stretches across the enormous diversity of life on Earth.
a Order Figure 1.1ba
b Regulation Figure 1.1bb
c Growth and development Figure 1.1bc
d Energy utilization Figure 1.1bd
e Response to the environment Figure 1.1be
f Reproduction Figure 1.1bf
g Evolution Figure 1.1bg
Life at Its Many Levels Biologists explore life at levels ranging from the biosphere to the molecules that make up cells.
Biosphere Figure 1.2a
Ecosystems Communities Figure 1.2b
Populations Organisms Figure 1.2c
Organ Systems and Organs Figure 1.2d
Tissues Figure 1.2e
Nucleus Cells Organelles Figure 1.2f
Atom Molecules and Atoms Figure 1.2g
Biosphere Ecosystems Communities Populations Organisms Organ Systems and Organs Tissues Organelles Nucleus Molecules and Atoms Atom Cells Figure 1.2-3
Concept Check Quiz Question 1 Which of the following levels of life s hierarchy is not appropriate when referring to two of life s domains: Archaea and Bacteria? a. the population level b. the organism level c. the organ level d. the molecular level
Inflow of light energy ECOSYSTEM Consumers animals Loss of heat energy Chemical energy food Producers plants and other photosynthetic organisms Cycling of nutrients Decomposers in soil Figure 1.3
Life in Its Diverse Forms Diversity is the hallmark of life. The diversity of known life includes 1.8 million species. Estimates of the total diversity range from 10 million to over 100 million species.
Grouping Species: The Basic Concept Biodiversity can be beautiful but overwhelming. Taxonomy is the branch of biology that names and classifies species. It formalizes the hierarchical ordering of organisms.
DOMAIN ARCHAEA TEM Colorized TEM DOMAIN BACTERIA Figure 1.8a
LM DOMAIN EUKARYA Kingdom Plantae Kingdom Fungi Kingdom Animalia Protists multiple kingdoms Figure 1.8b
These three multicellular kingdoms are distinguished by how they obtain food. Plants produce their own sugars and other foods by photosynthesis. Fungi are mostly decomposers, digesting dead organisms. Animals obtain food by eating and digesting other organisms.
Unity in the Diversity of Life Underlying the diversity of life is a striking unity, especially at the lower levels of structure. For example, all life uses the genetic language of DNA. Biological evolution accounts for this combination of unity and diversity.
EVOLUTION: BIOLOGY S UNIFYING THEME The history of life is a saga of a restless Earth billions of years old - http://youtu.be/farlfsymkey Fossils document this history - http://youtu.be/3rkgu0bitkm
Giant panda Ancestral bear Spectacled bear Sloth bear Sun bear American black bear Asiatic black bear Common ancestor of polar bear and brown bear Polar bear Brown bear 30 25 20 15 10 5 Millions of years ago Figure 1.10
The Darwinian View of Life The evolutionary view of life came into focus in 1859 when Charles Darwin published The Origin of Species. Figure 1.11a
Darwin s book developed two main points: Descent with modification Natural selection Observation 1: Overproduction and competition Observation 2: Individual variation Conclusion: Unequal reproductive success It is this unequal reproductive success that Darwin called natural selection. The product of natural selection is adaptation. Natural selection is the mechanism of evolution.
Population with varied inherited traits Elimination of individuals with certain traits Figure 1.12a
Reproduction of survivors Increasing frequency of traits that enhance survival and reproductive success Figure 1.12b
Concept Check Quiz Question 2 Darwin proposed the theory of natural selection. For the most part, natural selection acts as a filtering agent at the level of life s hierarchy. a. community b. population c. individual d. organ
Observing Artificial Selection Artificial selection is the selective breeding of domesticated plants and animals by humans. In artificial selection, humans do the selecting instead of the environment. Domesticated dogs descended from wolves Domesticated dogs Gray wolves Figure 1.13b
THE PROCESS OF SCIENCE The word science is derived from a Latin verb meaning to know. Science is a way of knowing. Science developed from people s curiosity about themselves and the world around them. Science seeks natural causes for natural phenomena. This limits the scope of science to the study of structures and processes that we can observe and measure. Verifiable observations and measurements are the data of discovery science. In biology, discovery science enables us to describe life at its many levels.
Hypothesis-Driven Science As a formal process of inquiry, the scientific method consists of a series of steps. The key element of the scientific method is hypothesis-driven science. A hypothesis is a proposed explanation for a set of observations an idea on trial. Once a hypothesis is formed, an investigator can use deductive logic to test it. In deduction, the reasoning flows from the general to the specific. In the process of science, the deduction usually takes the form of predictions about experimental results. Then the hypothesis is tested by performing an experiment to see whether results are as predicted.
Observation: My flashlight doesn t work. Question: What s wrong with my flashlight? Hypothesis: The flashlight s batteries are dead. Prediction: If I replace the batteries, the flashlight will work. Figure 1.15-1
Observation: My flashlight doesn t work. Question: What s wrong with my flashlight? Hypothesis: The flashlight s batteries are dead. Prediction: If I replace the batteries, the flashlight will work. Experiment: I replace the batteries with new ones. Experiment supports hypothesis; make additional predictions and test them. Figure 1.15-2
Revise Experiment does not support hypothesis; revise hypothesis or pose new one. Observation: My flashlight doesn t work. Question: What s wrong with my flashlight? Hypothesis: The flashlight s batteries are dead. Prediction: If I replace the batteries, the flashlight will work. Experiment: I replace the batteries with new ones. Experiment supports hypothesis; make additional predictions and test them. Figure 1.15-3
Theories in Science What is a scientific theory, and how is it different from a hypothesis? A theory is much broader in scope than a hypothesis. Theories only become widely accepted in science if they are supported by an accumulation of extensive and varied evidence. Scientific theories are not the only way of knowing nature. Science and religion are two very different ways of trying to make sense of nature.
Biology and Society Quiz Question 3 For some, religion and science seem to be at odds. Others feel that religion and science are two powerful but separate ways of human understanding. Most important, these people do not feel that science and religion are in conflict. Do you think that an individual can hold devout religious beliefs, while at the same time supporting scientific understanding? Strongly Agree A. B. C. D. E. Strongly Disagree
The Culture of Science Scientists build on what has been learned from earlier research. They pay close attention to contemporary scientists working on the same problem. Cooperation and competition characterize the scientific culture. Scientists check the conclusions of others by attempting to repeat experiments.
Biology and Society Quiz Question 4 Even a cursory glance at the news media reveals that scientific progress is an essential part of modern society. Still, many people are very skeptical of science. Do you think that scientists should take a more active role in helping society to understand and apply their findings? Strongly Agree A. B. C. D. E. Strongly Disagree
Biology and Society Quiz Question 5 Even a cursory glance at the news media reveals that scientific progress is an essential part of modern society. Still, many people are very skeptical of science. Do you think that an informed citizen needs a firm understanding of science to effectively participate in a representative society? Strongly Agree A. B. C. D. E. Strongly Disagree
Concept Check Quiz Question 6 Not all science discoveries strictly follow the scientific method. Which of the following would best be described as discovery science? a. sequencing the human genome b. describing a new bird species from the Philippines c. a project to find preserved specimens of the probably extinct Rocky Mountain locust frozen in glaciers d. all of the above
Interpreting Data These two snakes look remarkably similar to each other. The coral snake (right) is very poisonous to vertebrates. Hypotheses: H 1 : The coral snake s bright color pattern serves to warn off potential predators. H 2 : The king snake suffers less predation because it mimics or looks like the coral snake. H 3 : The protection that king snakes receive by mimicking coral snakes will depend on the presence of coral snakes.
Interpreting Data Quiz Question 7 A team of scientists designed an investigation that used artificial snakes to test the previous hypotheses. Which of the previous hypotheses are supported by the results displayed at the right? a. H 1 : The coral snake s bright color pattern serves to warn off potential predators. b. H 2 : The king snake suffers less predation because it mimics or looks like the coral snake. c. H 3 : The protection that king snakes receive by mimicking coral snakes will depend on the presence of coral snakes. d. both a and b
Interpreting Data Quiz Question 8 Biologists placed artificial snake mimics in two different localities to test the hypothesis that looking like a poisonous snake only works where the poisonous snake is found: 1. Outside of the coral snake range only king snakes are present. 2. Inside of the coral snake range both coral and king snakes are present.
Interpreting Data Quiz Question 9 The data graphed at the right the hypothesis that the effectiveness of mimic coloration depends on the presence of the poisonous model. a. supports b. does not support c. is irrelevant to
Interpreting Data Quiz Question 10 Based on this data, which of the following is a logical hypothesis or prediction? a. King snakes outside of the range of coral snakes will more closely resemble coral snakes than populations of king snakes living within the range of coral snakes. b. King snakes outside of the range of coral snakes will not resemble coral snakes as closely as populations of king snakes that live within the range coral snakes. c. Neither prediction is valid.