Biology: Exploring Life Chapter 1 Biology: Exploring Life

Themes in the Study of Biology Evolution, the Core Theme of Biology Figure 1.0_1 Chapter 1: Big Ideas Themes in the Study of Biology Evolution, the Core Theme of Biology The Process of Science Biology and Everyday Life 2

THEMES IN THE STUDY OF BIOLOGY © 2012 Pearson Education, Inc. 3

1.1 All forms of life share common properties Biology is the scientific study of life. Properties of life include Order—the highly ordered structure that typifies life, Reproduction—the ability of organisms to reproduce their own kind, Growth and development—consistent growth and development controlled by inherited DNA, Energy processing—the use of chemical energy to power an organism’s activities and chemical reactions, © 2012 Pearson Education, Inc. 4

1.1 All forms of life share common properties Response to the environment—an ability to respond to environmental stimuli, Regulation—an ability to control an organism’s internal environment within limits that sustain life, and Evolutionary adaptation—adaptations evolve over many generations as individuals with traits best suited to their environments have greater reproductive success and pass their traits to offspring. © 2012 Pearson Education, Inc. 5

(3) Growth and development (1) Order (4) Energy processing Figure 1.1 (3) Growth and development (1) Order (4) Energy processing (2) Reproduction (6) Regulation (5) Response to the environment (7) Evolutionary adaptation 6

1.2 In life’s hierarchy of organization, new properties emerge at each level Biological organization unfolds as follows: Biosphere—all of the environments on Earth that support life, Ecosystem—all the organisms living in a particular area and the physical components with which the organisms interact, Community—the entire array of organisms living in a particular ecosystem, Population—all the individuals of a species living in a specific area, © 2012 Pearson Education, Inc. 7

1.2 In life’s hierarchy of organization, new properties emerge at each level Organism—an individual living thing, Organ system—several organs that cooperate in a specific function, Organ—a structure that is composed of tissues and that provides a specific function for the organism, Tissues—a group of similar cells that perform a specific function, Cells—the fundamental unit of life, © 2012 Pearson Education, Inc. 8

1.2 In life’s hierarchy of organization, new properties emerge at each level Organelle—a membrane-bound structure that performs a specific function in a cell, and Molecule—a cluster of small chemical units called atoms held together by chemical bonds. © 2012 Pearson Education, Inc. 9

Figure 1.2 10 Biosphere Ecosystem: Forest in Madagascar Madagascar Community: All organisms in the forest Population: Group of ring-tailed lemurs Organism: Ring-tailed lemur Organ system: Nervous system Spinal cord Brain Organ: Brain Nerve Tissue: Nervous tissue Cell: Nerve cell Nucleus Atom Organelle: Nucleus Molecule: DNA 10

1.2 In life’s hierarchy of organization, new properties emerge at each level Emergent properties are new properties that arise in each step upward in the hierarchy of life, from the arrangement and interactions among component parts. © 2012 Pearson Education, Inc. 11

1.3 Cells are the structural and functional units of life Cells are the level at which the properties of life emerge. A cell can regulate its internal environment, take in and use energy, respond to its environment, develop and maintain its complex organization, and give rise to new cells. © 2012 Pearson Education, Inc. 12

1.3 Cells are the structural and functional units of life All cells are enclosed by a membrane that regulates the passage of materials between the cell and its surroundings and use DNA as their genetic information. © 2012 Pearson Education, Inc. 13

1.3 Cells are the structural and functional units of life There are two basic types of cells. Prokaryotic cells were the first to evolve, are simpler, and are usually smaller than eukaryotic cells. Eukaryotic cells contain membrane-enclosed organelles, including a nucleus containing DNA, and are found in plants, animals, and fungi. © 2012 Pearson Education, Inc. 14

Nucleus (membrane- enclosed) Figure 1.3 DNA (no nucleus) Prokaryotic cell Eukaryotic cell Membrane Organelles Nucleus (membrane- enclosed) DNA (throughout nucleus) 15

1.3 Cells are the structural and functional units of life Systems biology models the complex interactions of biological systems, ranging from the functioning of the biosphere to the complex molecular machinery of a cell. © 2012 Pearson Education, Inc. 16

1.3 Cells are the structural and functional units of life Cells illustrate another theme in biology: the correlation of structure and function. Structure is related to function at all levels of biological organization. © 2012 Pearson Education, Inc. 17

1.4 Living organisms interact with their environment, exchanging matter and energy Living organisms interact with their environments, which include other organisms and physical factors. In most ecosystems plants are the producers that provide the food, consumers eat plants and other animals, and decomposers act as recyclers, changing complex matter into simpler mineral nutrients. © 2012 Pearson Education, Inc. 18

1.4 Living organisms interact with their environment, exchanging matter and energy The dynamics of ecosystems include two major processes: The recycling of chemical nutrients from the atmosphere and soil through producers, consumers, and decomposers back to the environment. The one-way flow of energy through an ecosystem, entering as sunlight, converted to chemical energy by producers, passed on to consumers, and exiting as heat. © 2012 Pearson Education, Inc. 19

Ecosystem O2 O2 Sunlight Heat Producers (such as plants) Figure 1.4 Ecosystem O2 O2 Sunlight Heat Producers (such as plants) Consumers (such as animals) Chemical energy (food) CO2 CO2 Water and minerals taken up by tree roots Cycling of chemical nutrients Decomposers (in soil) 20

Ecosystem O2 O2 Sunlight Heat Producers (such as plants) Figure 1.4_1 Ecosystem O2 O2 Sunlight Heat Producers (such as plants) Consumers (such as animals) Chemical energy (food) CO2 CO2 Water and minerals taken up by tree roots Cycling of chemical nutrients Decomposers (in soil) 21

EVOLUTION, THE CORE THEME OF BIOLOGY © 2012 Pearson Education, Inc. 22

1.5 The unity of life is based on DNA and a common genetic code All cells have DNA, the chemical substance of genes. Genes are the unit of inheritance that transmits information from parents to offspring, are grouped into very long DNA molecules called chromosomes, and control the activities of a cell. © 2012 Pearson Education, Inc. 23

1.5 The unity of life is based on DNA and a common genetic code A species’ genes are coded in the sequences of the four building blocks making up DNA’s double helix. All forms of life use essentially the same code to translate the information stored in DNA into proteins. The diversity of life arises from differences in DNA sequences. © 2012 Pearson Education, Inc. 24

Figure 1.5 A T C G C G A T A C C G T A T A T C G G C 25

1.6 The diversity of life can be arranged into three domains We can think of biology’s enormous scope as having two dimensions. The “vertical” dimension is the size scale that stretches from molecules to the biosphere. The “horizontal” dimension spans across the great diversity of organisms existing now and over the long history of life on Earth. © 2012 Pearson Education, Inc. 26

1.6 The diversity of life can be arranged into three domains Diversity is the hallmark of life. Biologists have identified about 1.8 million species. Estimates of the actual number of species ranges from 10 to 100 million. Taxonomy names species and classifies them into a system of broader groups. © 2012 Pearson Education, Inc. 27

1.6 The diversity of life can be arranged into three domains Bacteria are the most diverse and widespread prokaryotes. Archaea are prokaryotes that often live in Earth’s extreme environments. Eukarya have eukaryotic cells and include single-celled protists and multicellular fungi, animals, and plants. © 2012 Pearson Education, Inc. 28

Domain Bacteria Domain Eukarya Domain Archaea Bacteria Figure 1.6 Domain Bacteria Domain Eukarya Bacteria Domain Archaea Protists (multiple kingdoms) Kingdom Plantae Archaea Kingdom Fungi Kingdom Animalia 29

1.7 Evolution explains the unity and diversity of life The history of life, as documented by fossils, is a saga of a changing Earth billions of years old and inhabited by an evolving cast of life forms. Evolution accounts for life’s dual nature of kinship and diversity. © 2012 Pearson Education, Inc. 30

1.7 Evolution explains the unity and diversity of life In 1859, Charles Darwin published the book On the Origin of Species by Means of Natural Selection, which articulated two main points. 1. A large amount of evidence supports the idea of evolution, that species living today are descendants of ancestral species in what Darwin called “descent with modification.” 2. Natural selection is a mechanism for evolution. © 2012 Pearson Education, Inc. 31

1.7 Evolution explains the unity and diversity of life Natural selection was inferred by connecting two observations. Individuals in a population vary in their traits, many of which are passed on from parents to offspring. A population can produce far more offspring than the environment can support. © 2012 Pearson Education, Inc. 32

Population with varied inherited traits Figure 1.7C 1 Population with varied inherited traits 2 Elimination of individuals with certain traits 3 Reproduction of survivors 33

1.7 Evolution explains the unity and diversity of life From these observations, Darwin inferred that those individuals with heritable traits best suited to the environment are more likely to survive and reproduce than less well-suited individuals, as a result of this unequal reproductive success over many generations, an increasing proportion of individuals will have the advantageous traits, and the result will be evolutionary adaptation, the accumulation of favorable traits in a population over time. © 2012 Pearson Education, Inc. 34

THE PROCESS OF SCIENCE © 2012 Pearson Education, Inc. 35

1.8 Scientific inquiry is used to ask and answer questions about nature The word science is derived from a Latin verb meaning “to know.” Science is a way of knowing. Scientists use inductive reasoning to draw general conclusions from many observations and deductive reasoning to come up with ways to test a hypothesis, a proposed explanation for a set of observations.The logic flows from general premises to the specific results we should expect if the premises are true. © 2012 Pearson Education, Inc. 36

1.8 Scientific inquiry is used to ask and answer questions about nature How is a theory different from a hypothesis? A scientific theory is much broader in scope than a hypothesis, usually general enough to generate many new, specific hypotheses, which can then be tested, and supported by a large and usually growing body of evidence. © 2012 Pearson Education, Inc. 37

1.9 Scientists form and test hypotheses and share their results We solve everyday problems by using hypotheses. A common example would be the reasoning we use to answer the question, “Why doesn’t a flashlight work?” Using deductive reasoning we realize that the problem is either (1) the bulb or (2) the batteries. Further, a hypothesis must be testable and falsifiable. In this example, two hypotheses are tested. © 2012 Pearson Education, Inc. 38

Observation Question Hypothesis 1: Hypothesis 2: Dead batteries Figure 1.9A_s1 Observation Question Hypothesis 1: Hypothesis 2: Dead batteries Burned-out bulb 39

Prediction: Prediction: Experiment: Experiment: Figure 1.9A_s2 Observation Question Hypothesis 1: Hypothesis 2: Dead batteries Burned-out bulb Prediction: Prediction: Replacing batteries will fix problem. Replacing bulb will fix problem. Experiment: Experiment: Test prediction by replacing batteries. Test prediction by replacing bulb. 40

Prediction: Prediction: Experiment: Experiment: Figure 1.9A_s3 Observation Question Hypothesis 1: Hypothesis 2: Dead batteries Burned-out bulb Prediction: Prediction: Replacing batteries will fix problem. Replacing bulb will fix problem. Experiment: Experiment: Test prediction by replacing batteries. Test prediction by replacing bulb. Test does not falsify hypothesis. Make additional predictions and test them. Test falsifies hypothesis. Revise hypothesis or pose new one. 41

1.9 Scientists form and test hypotheses and share their results An actual research project demonstrates the process of science. Scientists began with a set of observations and generalizations that poisonous animals are brightly colored and imposters resemble poisonous species but are actually harmless. They then tested the hypothesis that mimics benefit because predators confuse them with the harmful species. © 2012 Pearson Education, Inc. 42

1.9 Scientists form and test hypotheses and share their results The scientists conducted a controlled experiment, comparing an experimental group consisting of artificial king snakes and a control group consisting of artificial brown snakes. The groups differed only by one factor, the coloration of the artificial snakes. The data fit the key prediction of the mimicry hypothesis. © 2012 Pearson Education, Inc. 43

Figure 1.9B 44

Figure 1.9C 45

Figure 1.9D 46

Percent of total attacks on artificial snakes Figure 1.9E 100 Artificial king snakes 84% 83% 80 Artificial brown snakes Percent of total attacks on artificial snakes 60 40 20 17% 16% Coral snakes absent Coral snakes present 47

1.9 Scientists form and test hypotheses and share their results Science is a social activity with most scientists working in teams. Scientists share information in many ways. Science seeks natural causes for natural phenomena. The scope of science is limited to the study of structures and processes that we can directly observe and measure. Hypotheses about supernatural forces or explanations are outside the bounds of science, because they generate hypotheses that cannot be tested by science. © 2012 Pearson Education, Inc. 48

1.11 EVOLUTION CONNECTION: Evolution is connected to our everyday lives Evolution is a core theme of biology. Evolutionary theory is useful in medicine, agriculture, forensics, and conservation. © 2012 Pearson Education, Inc. 49