Chapt 1

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Chapter 1

Biology: Exploring Life

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Campbell Biology: Concepts & Connections, Eighth Edition

REECE • TAYLOR • SIMON • DICKEY • HOGAN

Lecture by Edward J. Zalisko

Introduction

• Snowy owls exhibit adaptations for life in their frozen, barren habit, including • feathers that provide insulation in subzero weather and • keen vision and acute hearing that help owls locate prey.

• Snowy owls are the result of evolution, the process that has transformed life from its earliest beginnings.

THEMES IN THE STUDY OF BIOLOGY

T HEMES IN THE S TUDY OF B IOLOGY

How can we differentiate Life from Non-Life?

All forms of life share common properties

Order

Reproduction

Growth and development

Energy processing

Regulation

Response to the environment

Evolutionary adaptation

Sea Horses

Notice the Evolutionary adaptation to their environment

life exhibits a hierarchy of organization, as you move up this hierarchy, new properties emerge at each level

Biosphere Florida Ecosystem Community All organisms in this wetland ecosystem Florida Everglades Population All alligators living in the wetlands Organism an American alligator

Nerve Spinal cord Organism an American alligator Organ system Nervous system Brain Organ Brain Tissue Nervous tissue Cell Nerve cell Nucleus Organelle Nucleus

Atom Molecule DNA

•

Emergent properties

are new properties that arise in each step upward in the hierarchy of life from the arrangement and interactions among component parts.

Cells are the structural and functional units of life

• Cells are the level at which the properties of life emerge.

The structural characteristics of cells

• 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.

• There are two basic forms of cells.

• • •

Prokaryotic cells

were the first to evolve, are simpler, and are usually smaller than eukaryotic cells.

• •

Eukaryotic cells

are found in plants, animals, fungi, and protists and are subdivided by membranes into various functional compartments, or organelles, including a nucleus that houses the DNA.

Eukaryotic cell Prokaryotic cell DNA (no nucleus) Membrane Organelles Nucleus (membrane enclosed) DNA (throughout nucleus)

The functional characteristics of cells

•

Systems biology

is the study of a biological system and the modeling of its dynamic behavior, ranging from the functioning of the biosphere to the complex molecular machinery of an organelle.

• Cells illustrate another theme in biology: the correlation of structure and function.

• Structure is related to function at all levels of biological organization.

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 chemicals that plants can absorb and use.

• The dynamics of ecosystems include two major processes: 1.

the recycling of chemical nutrients from the atmosphere and soil through producers, consumers, and decomposers back to the air and soil and the one-way flow of energy through an ecosystem, entering as sunlight and exiting as heat.

Figure 1.4-0

Sun Inflow of light energy ENERGY FLOW Outflow of heat Leaves take up CO 2 from air; roots absorb H 2 O and minerals from soil

Producers (plants) Chemical energy in food Consumers (animals) Decomposers such as worms, fungi, and bacteria return chemicals to soil

Figure 1.4-1

Sun Inflow of light energy ENERGY FLOW Outflow of heat Leaves take up CO 2 from air; roots absorb H 2 O and minerals from soil

Producers (plants) Chemical energy in food Consumers (animals) Decomposers such as worms, fungi, and bacteria return chemicals to soil

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 transmit information from parents to offspring, • are grouped into very long DNA molecules called chromosomes, and • control the activities of a cell.

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 kinds of 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.

Cell Nucleus DNA T C A G G G C C C C G G T A A C T A G T C G G C C G T A A A T T T A

Cell Nucleus DNA G G C C C C G G T A A T

T C A G C A G T C G G C C G T A A A T T T A

1.5 The unity of life is based on DNA and a common genetic code

• The entire “library” of genetic instructions that an organism inherits is called its

genome

• In recent years, scientists have determined the entire sequence of nucleotides in the human genome.

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.

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 range from 10 million to over 100 million.

• Taxonomy is the branch of biology that • • names species and classifies species into a hierarchy of broader groups: genus, family, order, class, phylum, and kingdom.

1.6 The diversity of life can be arranged into three domains

• The diversity of life can be arranged into three higher levels called

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.

Figure 1.6-0

Domain Bacteria Domain Eukarya Bacteria Domain Archaea Protists (multiple kingdoms) Kingdom Plantae Archaea

Kingdom Fungi Kingdom Animalia

Figure 1.6-1

Domain Bacteria

Bacteria

Figure 1.6-2

Domain Archaea

Archaea

Figure 1.6-3

Domain Eukarya Protists (multiple kingdoms) Kingdom Plantae

Kingdom Fungi Kingdom Animalia

Protists (multiple kingdoms)

Kingdom Plantae

Kingdom Fungi

Kingdom Animalia

VOLUTION

THE OF

ORE

IOLOGY

HEME

1.7 Evolution explains the unity and diversity of life

•

Evolution

can be defined as the process of change that has transformed life on Earth from its earliest beginnings to the diversity of organisms living today.

• The fossil record documents • that life has been evolving on Earth for billions of years and • the pattern of ancestry.

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.

Species living today descended from ancestral species in what Darwin called “descent with modification.”

Natural selection

is a mechanism for evolution.

• Natural selection was inferred by connecting two observations.

Individual variation

: Individuals in a population vary in their traits, many of which are passed on from parents to offspring.

Overproduction of offspring

: A population can produce far more offspring than the environment can support.

• From these observations, Darwin drew two inferences.

Unequal reproductive success

: Individuals with heritable traits best suited to the environment are more likely to survive and reproduce than less well-suited individuals.

Accumulation of favorable traits over time

: As a result of this unequal reproductive success over many generations, an increasing proportion of individuals in a population will have the advantageous traits.

1 Population with varied inherited traits.

2 Elimination of individuals with certain traits and reproduction of survivors.

1 Population with varied inherited traits.

2 Elimination of individuals with certain traits and reproduction of survivors.

3 Increasing frequency of traits that enhance survival and reproductive success.

• Darwin realized that numerous small changes in populations as a result of natural selection could eventually lead to major alterations of species.

• The fossil record provides evidence of such diversification of species from ancestral species.

Deinotherium Mammut Platybelodon Stegodon Mammuthus Elephas maximus

(Asia)

Loxodonta africana

(Africa) 34 24 Millions of years ago 5.5 2 10 4 0

Loxodonta cyclotis

(Africa) Years ago

HE

ROCESS OF

CIENCE

• Science is a way of knowing that stems from our curiosity about ourselves and the world around us.

• Science is based upon inquiry, the search for information and explanations of natural phenomena.

• Scientists typically • make observations, • form

hypotheses

, proposed explanations for a set of observations, and • test them.

• Two types of data are frequently collected in scientific investigations.

Qualitative

data is descriptive.

Quantitative

data includes numerical measurements.

• Scientists use two types of reasoning.

Inductive reasoning makes generalizations based on collecting and analyzing a large number of specific observations.

Deductive reasoning flows from general premises to predicted and specific 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?” • Two reasonable hypotheses are that 1.

the batteries are dead or the bulb is burned out.

Figure 1.8-1

Observation: Flashlight doesn’t work.

Question: Why doesn’t the flashlight work?

Hypothesis #1: Batteries are dead.

Hypothesis #2: Bulb is burned out.

Figure 1.8-2

Observation: Flashlight doesn’t work.

Question: Why doesn’t the flashlight work?

Hypothesis #1: Batteries are dead.

Prediction: Replacing batteries will fix problem.

Test of prediction: Replace batteries.

Hypothesis #2: Bulb is burned out.

Prediction: Replacing bulb will fix problem.

Test of prediction: Replace bulb.

Figure 1.8-3

Observation: Flashlight doesn’t work.

Question: Why doesn’t the flashlight work?

Hypothesis #1: Batteries are dead.

Prediction: Replacing batteries will fix problem.

Hypothesis #2: Bulb is burned out.

Prediction: Replacing bulb will fix problem.

Test of prediction: Replace batteries.

Test of prediction: Replace bulb.

Results: Flashlight doesn’t work.

Hypothesis is contradicted.

Results: Flashlight works.

Hypothesis is supported.

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.

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.

Figure 1.9B

Figure 1.9C

Figure 1.9D

Figure 1.9E

100 80 83% 60 84% 40 20 17% 16% 0 Coral snakes absent Coral snakes present

Artificial king snakes Artificial brown snakes

• A scientific

theory

• • is much broader in scope than a hypothesis and supported by a large and usually growing body of evidence.

• A primary function of science is to Make and Use Theories.

IOLOGY AND

VERYDAY

IFE

Evolution is connected to our everyday lives

• Humans selectively breed plants and animals in the process of

artificial selection

• move productive crops, • • better livestock, and to produce a great variety of pets that bear little resemblance to their wild ancestors.

• Humans also unintentionally cause • • • the evolution of antibiotic-resistant bacteria, the evolution of pesticide-resistant pests, and the loss of species through habitat loss and global climate change.

Figure 1.10

Biology, technology, and society are connected in important ways

• Many issues facing society • • are related to biology and often involve our expanding technology.

• The basic goals of science and technology differ.

• The goal of science is to understand natural phenomena.

• The goal of

technology

is to apply scientific knowledge for some specific purpose.

• Although their goals differ, science and technology are interdependent.

• Research benefits from new technologies.

• Technological advances stem from scientific research.

• Technologies of DNA manipulation are the results of scientific discovery of the structure of DNA.

EVIEW AND

TUDY

Describe seven properties common to all life.

Describe the levels of biological organization from molecules to the biosphere, noting the interrelationships between levels.

Define the concept of emergent properties and describe an example of it.

Explain why cells are a special level in biological organization. Compare prokaryotic and eukaryotic cells.

Compare the dynamics of nutrients and energy in an ecosystem.

Explain how DNA encodes a cell’s information.

Compare the three domains of life.

Describe the process and products of natural selection.

Distinguish between quantitative and qualitative data.

10.

Compare the definitions and use of inductive and deductive reasoning in scientific investigations.

11.

Distinguish between a scientific theory and a hypothesis.

12.

Describe the structure of a controlled experiment and give an example.

13.

Explain how evolution impacts the lives of all humans.

14.

Compare the goals of science and technology. Explain why an understanding of science is essential to our lives.