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- Herausgeber: John Wiley & Sons
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
- Veröffentlichungsjahr: 2019
Biology Essentials For Dummies (9781119589587) was previously published as Biology Essentials For Dummies (9781118072677). While this version features a new Dummies cover and design, the content is the same as the prior release and should not be considered a new or updated product. Just the core concepts you need to score high in your biology course Biology Essentials For Dummies focuses on just the core concepts you need to succeed in an introductory biology course. From identifying the structures and functions of plants and animals to grasping the crucial discoveries in evolutionary, reproductive, and ecological biology, this easy-to-follow guide lets you skip the suffering and score high at exam time. * Get down to basics -- master the fundamentals, from understanding what biologists study to how living things are classified * The chemistry of life -- find out what you need to know about atoms, elements, molecules, compounds, acids, bases, and more * Conquer and divide -- discover the ins and outs of asexual and sexual reproduction, including cell division and DNA replication Jump into the gene pool -- grasp how proteins make traits happen, and easily understand DNA transcription, RNA processing, translation, and gene regulation.
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Biology Essentials For Dummies®
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ISBN: 978-1-119-58958-7 (pbk); ISBN: 978-1-119-58962-4 (ePDF); ISBN: 978-1-119-58954-9 (ePub)
Biology Essentials For Dummies®
To view this book's Cheat Sheet, simply go to www.dummies.com and search for “Biology Essentials For Dummies Cheat Sheet” in the Search box.
Table of Contents
Cover
Introduction
About This Book
Conventions Used in This Book
Foolish Assumptions
Icons Used in This Book
Beyond the Book
Where to Go from Here
Chapter 1: Exploring the Living World
Living Things: Why Biologists Study Them, What Defines Them
Meet Your Neighbors: Looking at Life on Earth
Classifying Living Things
Organizing Life into Smaller and Smaller Groups: Taxonomy
Biodiversity: Our Differences Make Us Stronger
Making Sense of the World through Observations
Chapter 2: The Chemistry of Life
Exploring Why Matter Matters
The Differences among Atoms, Elements, and Isotopes
Molecules, Compounds, and Bonds
Acids and Bases
Carbon-Based Molecules: The Basis for All Life
Chapter 3: The Living Cell
An Overview of Cells
Peeking at Prokaryotic Cells
Examining the Structure of Eukaryotic Cells
Cells and the Organelles
Presenting Enzymes, the Jump-Starters
Chapter 4: Energy and Organisms
What’s Energy Got to Do with It?
Building Cells through Photosynthesis
Cellular Respiration: Using Oxygen to Break Down Food
Energy and Your Body
Chapter 5: Reproducing Cells
Reproduction: Keep On Keepin’ On
How DNA Replication Works
Cell Division: Out with the Old, In with the New
How Sexual Reproduction Creates Genetic Variation
This Budding’s for You: Asexual Reproduction
Chapter 6: DNA and Proteins: Life Partners
Proteins Make Traits Happen, and DNA Makes the Proteins
Moving from DNA to RNA to Protein
Mistakes Happen: The Consequences of Mutation
Giving Cells Some Control: Gene Regulation
Chapter 7: Ecosystems and Populations
Ecosystems Bring It All Together
Studying Populations
Moving Energy and Matter around within Ecosystems
Chapter 8: Understanding Genetics
Heritable Traits and the Factors Affecting Them
Mendel’s Laws of Inheritance
Defining Key Genetics Terms
Bearing Genetic Crosses
Genetic Engineering
Chapter 9: Biological Evolution
What People Used to Believe
Charles Darwin: Challenging Age-Old Beliefs
Evidence of Biological Evolution
Evolution versus Creationism
Chapter 10: Ten Great Biology Discoveries
Seeing the Unseen
Creating the First Antibiotic
Protecting People from Smallpox
Defining DNA Structure
Finding and Fighting Defective Genes
Discovering Modern Genetic Principles
Evolving the Theory of Natural Selection
Formulating Cell Theory
Moving Energy through the Krebs Cycle
Amplifying DNA with PCR
Index
About the Authors
Advertisement Page
Connect with Dummies
End User License Agreement
List of Tables
Chapter 1
TABLE 1-1 Comparing the Taxonomy of Several Species
Chapter 4
TABLE 4-1 Determining Caloric Need Based on Lifestyle
Chapter 5
TABLE 5-1 A Comparison of Mitosis and Meiosis
Chapter 8
TABLE 8-1 Some Beneficial Genetically Engineered Proteins
List of Illustrations
Chapter 2
FIGURE 2-1: A variety of carbohydrate molecules.
FIGURE 2-2: Amino acid structure.
FIGURE 2-3: The twisted-ladder model of a DNA double helix.
FIGURE 2-4: Saturated and unsaturated bonds in a typical triglyceride.
Chapter 3
FIGURE 3-1: Cells perform all the functions of life.
FIGURE 3-2: A prokaryotic cell.
FIGURE 3-3: Structures in a typical plant cell.
FIGURE 3-4: Structures in a typical animal cell.
FIGURE 3-5: The fluid-mosaic model of plasma membranes.
FIGURE 3-6: Enzyme catalysis.
Chapter 4
FIGURE 4-1: The ATP/ADP cycle.
FIGURE 4-2: The two halves of photosynthesis, the light reactions and the light-...
FIGURE 4-3: An overview of cellular respiration.
FIGURE 4-4: The events happening inside mitochondria, as described by the chemio...
Chapter 5
FIGURE 5-1: DNA replication.
FIGURE 5-2: Interphase and mitosis.
FIGURE 5-3: Cytokinesis.
FIGURE 5-4: A human karyotype.
FIGURE 5-5: The human life cycle.
FIGURE 5-6: Crossing-over, meiosis, and nondisjunction.
Chapter 6
FIGURE 6-1: Transcribing DNA and processing mRNA within the nucleus of an eukary...
FIGURE 6-2: The genetic code.
FIGURE 6-3: Translating mRNA into protein.
Chapter 7
FIGURE 7-1: The organization of living things.
FIGURE 7-2: Age-structure diagrams break down age groups in populations.
FIGURE 7-3: Human population growth.
FIGURE 7-4: The energy pyramid.
FIGURE 7-5: The carbon cycle.
FIGURE 7-6: The nitrogen cycle.
Chapter 8
FIGURE 8-1: Punnett squares showing Mendel’s cross between tall and short pea pl...
FIGURE 8-2: Restriction enzymes.
FIGURE 8-3: DNA sequencing.
Chapter 9
FIGURE 9-1: Natural selection in action.
FIGURE 9-2: Comparative anatomy of the bones in front limbs of humans, cats, wha...
Guide
Cover
Table of Contents
Begin Reading
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Introduction
Life is all around you, from invisible microbes and green plants to the other animals with whom you share the Earth. What’s more, these other living things aren’t just around you — they’re intimately interconnected with your life. Plants make your food and provide you with oxygen, microbes break down dead matter and recycle materials that all living things need, and insects pollinate the plants you rely on for food. Ultimately, all living beings rely on other living beings for their survival.
What makes biology so great is that it allows you to explore the interconnectedness of the world’s organisms and really understand that living beings are works of art and machines rolled into one. Organisms can be as delicate as a mountain wildflower or as awe-inspiring as a majestic lion. And regardless of whether they’re plants, animals, or microbes, all living things have numerous working parts that contribute to the function of the whole being. They move, obtain energy, use raw materials, and make waste, whether they’re as simple as a single-celled organism or as complex as a human being.
Biology is the key you need to unlock the mysteries of life. Through it, you discover that even single-celled organisms have their complexities, from their unique structures to their diverse metabolisms. Biology also helps you realize what a truly miraculous machine your body is, with its many different systems that work together to move materials, support your structure, send signals, defend you from invaders, and obtain the matter and energy you need for growth.
About This Book
Biology Essentials For Dummies takes a look at the characteristics all living things share. It also provides an overview of the concepts and processes that are fundamental to living things. We put an emphasis on looking at how human beings meet their needs, but we also take a look at the diversity of life on planet Earth.
Conventions Used in This Book
To help you find your way through the subjects in this book, we use the following style conventions:
Italics
highlight new words or terms that are defined in the text. They also point out words we want to emphasize.
Also, whenever we introduce scientific terms, we try to break the words down for you so that the terms become tied to their meanings, making them easier to remember.
Foolish Assumptions
As we wrote this book, we tried to imagine who you are and what you need in order to understand biology. Here’s what we came up with:
You’re a high school student taking biology, possibly in preparation for an advanced placement test or college entrance examination. If you’re having trouble in biology class and your textbook isn’t making much sense, try reading the relevant section of this book first to give yourself a foundation and then go back to your textbook or notes.
You’re a college student who isn’t a science major but is taking a biology class to help fulfill your degree requirements. If you want help following along in class, try reading the relevant sections in this book before you go to a lecture on a particular topic. If you need to fix a concept in your brain, read the related section after class.
Icons Used in This Book
We use some of the familiar For Dummies icons to help guide you and give you new insights as you read the material. Here’s the scoop on what each one means.
The information highlighted with this icon is stuff we think you should permanently store in your mental biology file. If you want a quick review of biology, scan through the book reading only the paragraphs marked with Remember icons.
This symbol offers pointers that help you remember the facts presented in a particular section so you can better commit them to memory.
Beyond the Book
In addition to what you’re reading right now, this book comes with a free access-anywhere Cheat Sheet. To get this Cheat Sheet, go to www.dummies.com and search for “Biology Essentials For Dummies Cheat Sheet” by using the Search box.
Where to Go from Here
Where you start reading is up to you. However, we do have a few suggestions:
If you’re currently in a biology class and having trouble with a particular topic, jump right to the chapter or section featuring the subject that’s confusing you.
If you’re using this book as a companion to a biology class that’s just beginning, you can follow along with the topics being discussed in class.
Whatever your situation, the table of contents and index can help you find the information you need.
Chapter 1
Exploring the Living World
IN THIS CHAPTER
Identifying the characteristics of living things
Introducing the three main types of living things
Organizing living things into groups
Valuing the diversity of life on Earth
Observing the world like a scientist
Biology is the study of life, as in the life that covers the surface of the Earth like a living blanket, filling every nook and cranny from dark caves and dry deserts to blue oceans and lush rain forests. Living things interact with all these environments and each other, forming complex, interconnected webs of life.
In this chapter, we give you an overview of the big concepts of biology. Our goal is to show you how biology connects to your life and to give you a preview of the topics we explore in greater detail later in this book.
Living Things: Why Biologists Study Them, What Defines Them
Biologists seek to understand everything they can about living things, including
The structure and function of all the diverse living things on planet Earth
The relationships between living things
How living things grow, develop, and reproduce, including how these processes are regulated by DNA, hormones, and nerve signals
The connections between living things and their environment
How living things change over time
How DNA changes, how it’s passed from one living thing to another, and how it controls the structure and function of living things
An individual living thing is called an organism. All organisms share eight specific characteristics that define the properties of life:
Living things are made of cells that contain DNA.
A
cell
is the smallest part of a living thing that retains all the properties of life. In other words, it’s the smallest unit that’s alive.
DNA,
short for
deoxyribonucleic acid,
is the genetic material, or instructions, for the structure and function of cells.
Living things maintain order inside their cells and bodies.
One law of the universe is that everything tends to become random over time. According to this law, if you build a sand castle, it’ll crumble back into sand over time. Living things, as long as they remain alive, don’t crumble into little bits. They constantly use energy to rebuild and repair themselves so that they stay intact.
Living things regulate their systems.
Living things maintain their internal conditions in a way that supports life. Even when the environment around them changes, organisms attempt to maintain their internal conditions; this process is called
homeostasis.
Think about what happens when you go outside on a cool day without wearing a coat. Your body temperature starts to drop, and your body responds by pulling blood away from your extremities to your core in order to slow the transfer of heat to the air. It may also trigger shivering, which gets you moving and generates more body heat. These responses keep your internal body temperature in the right range for your survival even though the outside temperature is low.
Living things respond to signals in the environment.
If you pop up suddenly and say “Boo!” to a rock, it doesn’t do anything. Pop up and say “Boo!” to a friend or a frog, and you’ll likely see him or it jump. That’s because living things have systems to sense and respond to signals (or
stimuli
). Many animals sense their environment through their five senses just like you do, but even less familiar organisms, such as plants and bacteria, can sense and respond. For example, during the process of
phototaxis,
plants direct their growth toward areas where they have access to light.
Living things transfer energy among themselves and between themselves and their environment.
Living things need a constant supply of energy to grow and maintain order. Organisms such as plants capture light energy from the sun and use it to build food molecules that contain chemical energy. Then the plants, and other organisms that eat the plants, transfer the chemical energy from the food into cellular processes. As cellular processes occur, they transfer most of the energy back to the environment as heat.
Living things grow and develop.
You started life as a single cell. That cell divided to form new cells, which divided again. Now your body is made of approximately 100 trillion cells. As your body grew, your cells received signals that told them to change and become special types of cells: skin cells, heart cells, liver cells, brain cells, and so on. Your body developed along a plan, with a head at one end and a “tail” at the other. The DNA in your cells controlled all these changes as your body developed.
Living things reproduce.
People make babies, hens make chicks, and plasmodial slime molds make plasmodial slime molds. When organisms reproduce, they pass copies of their DNA onto their offspring, ensuring that the offspring have some of the traits of the parents.
Living things have traits that evolved over time.
Birds can fly, but most of their closest relatives — the dinosaurs — couldn’t. The oldest feathers seen in the fossil record are found on a feathered dinosaur called
Archaeopteryx.
No birds or feathers have been found in any fossils that are older than those of
Archaeopteryx.
From observations like these, scientists can infer that having feathers is a trait that wasn’t always present on Earth; rather, it’s a trait that developed at a certain point in time. So, today’s birds have characteristics that developed through the evolution of their ancestors.
Meet Your Neighbors: Looking at Life on Earth
Life on Earth is incredibly diverse, beautiful, and complex. Heck, you could spend a lifetime exploring the microbial universe alone. The deeper you delve into the living world around you, the more you can appreciate the similarities between all life on Earth — and be fascinated by the differences. The following sections give you a brief introduction to the major categories of life on Earth (called domains, as we explain in the upcoming section “Organizing Life into Smaller and Smaller Groups: Taxonomy”).
Unsung heroes: Bacteria
Consisting mostly of single-celled organisms, bacteria are prokaryotic, meaning they lack a nuclear membrane around their DNA. Most bacteria have a cell wall made of peptidoglycan: a hybrid sugar-protein molecule.
Most people are familiar with disease-causing bacteria such as Streptococcus pyogenes, Mycobacterium tuberculosis, and Staphylococcus aureus. Yet the vast majority of bacteria on Earth don’t cause human diseases. Instead, they play important roles in the environment and health of living things, including humans. Photosynthetic bacteria make significant contributions to planetary food and oxygen production, and E. coli living in your intestines make vitamins that you need to stay healthy. So when you get down to it, plants and animals couldn’t survive on Earth without bacteria.
Generally speaking, bacteria range in size from 1 to 10 micrometers (one millionth of a meter) in length and are invisible to the naked eye. Along with being nucleus-free, they have a genome that’s a single circle of DNA. They reproduce asexually (meaning they produce copies of themselves) by a process called binary fission.
Bacteria have many ways of getting the energy they need for growth and various strategies for surviving in extreme environments. Their great metabolic diversity has allowed them to colonize just about every environment on Earth.
Bacteria impersonators: Archaeans
Archaeans are prokaryotes, just like bacteria. In fact, you can’t tell the difference between the two just by looking, even if you look very closely using an electron microscope, because they’re about the same size and shape, have similar cell structures, and divide by binary fission.
Until the 1970s, no one even knew that archaeans existed; up to that point, all prokaryotic cells were assumed to be bacteria. Then, in the 1970s, a scientist named Carl Woese started doing genetic comparisons between prokaryotes. Woese startled the entire scientific world when he revealed that prokaryotes actually separated into two distinct groups — bacteria and archaea — based on sequences in their genetic material.
The first archaeans were discovered in extreme environments (think salt lakes and hot springs), so they have a reputation for being extremophiles (-phile means “love,” so extremophiles means “extreme-loving”). Since their initial discovery, however, archaeans have been found everywhere scientists have looked for them. They’re happily living in the dirt outside your home right now, and they’re abundant in the ocean.
Because archaeans were discovered fairly recently, scientists are still learning about their role on planet Earth, but so far it looks like they’re as abundant and successful as bacteria.
A taste of the familiar: Eukaryotes
Unless you’re a closet biologist, you’re probably most familiar with life in eukaryotic form because you encounter it every day. As soon as you step outside, you can find a wealth of plants and animals (and maybe even a mushroom or two if you look around a little).
On the most fundamental level, all eukaryotes are quite similar. They share a common cell structure with nuclei and organelles, use many of the same metabolic strategies, and reproduce either asexually or sexually.
Despite these similarities, we bet you still feel that you’re pretty different from a carrot. You’re right to feel that way. The differences between you and a carrot are what separate you into two different kingdoms. In fact, enough differences exist among eukaryotes to separate them into four different kingdoms:
Animalia:
Animals are organisms that begin life as a cell called a
zygote
that results from the fusion of a sperm and an egg. The fertilized egg then divides to form a hollow ball of cells called a
blastula.
If you’re wondering when the fur, scales, and claws come into play, these familiar animal characteristics get factored in much later, at the point when animals get divided up into phyla, families, and orders (see the “
Organizing Life into Smaller and Smaller Groups: Taxonomy
” section later in this chapter for more on these groupings).
Plantae: Plants are photosynthetic organisms that start life as embryos supported by maternal tissue. This definition of plants includes all the plants you’re familiar with: pine trees, flowering plants (including carrots), grasses, ferns, and mosses. All plants have cells with cell walls made of cellulose. They reproduce asexually by mitosis, but they can also reproduce sexually.
The definition of plants, which specifies a stage where an embryo is supported by maternal tissue, excludes most of the algae, like seaweed, found on Earth. Algae and plants are so closely related that many people include algae in the plant kingdom, but many biologists draw the line at including algae in the plant kingdom.
Fungi:
Fungi may look a bit like plants, but they aren’t photosynthetic. They get their nutrition by breaking down and digesting dead matter. Their cells have walls made of
chitin
(a strong, nitrogen-containing polysaccharide). This kingdom includes mushrooms, molds that you see on your bread and cheese, and many rusts that attack plants. Yeast is also a member of this kingdom even though it grows differently; most fungi grow as filaments (that look like threads), but yeast grow as little oval cells.
Protista:
This kingdom is defined as everything else that’s eukaryotic. Seriously. Biologists have studied animals, plants, and fungi for a long time and defined them as distinct groups long ago. But many, many, eukaryotes don’t fit into these three kingdoms. A whole world of microscopic protists exists in a drop of pond water. The protists are so diverse that some biologists think they should be separated into as many as 11 kingdoms of their own.
Classifying Living Things
Much like you’d draw a family tree to show the relationships between your parents, grandparents, and other members of your family, biologists use a phylogenetic tree (a drawing that shows the relationships among a group of organisms) to represent the relationships among living things.
Although you probably know how your family members are related to each other, biologists have to use clues to figure out the relationships among living things. The types of clues they use to figure out these relationships include
Physical structures:
The structures that biologists use for comparison may be large, like feathers, or very small, like a cell wall.
Chemical components:
Some organisms produce unique chemicals. Bacteria, for example, are the only cells that make the hybrid sugar-protein molecule called peptidoglycan.
Genetic information:
An organism’s genetic code determines its traits, so by reading the genetic code in DNA, biologists can go right to the source of differences among species.
The more characteristics two organisms have in common with each other, the more closely related they are. Characteristics that organisms have in common are called shared characteristics.
Based on structural, cellular, biochemical, and genetic characteristics, biologists can classify life on Earth into groups that reflect the evolutionary history of the planet. That history indicates that all life on Earth began from one original universal ancestor after the Earth formed 4.5 billion years ago. All the diversity of life that exists today is related because it’s descended from that original ancestor.
Organizing Life into Smaller and Smaller Groups: Taxonomy
Biologists need to work with small groups of living things in order to determine how similar the different types of organisms are. Hence, the creation of the taxonomic hierarchy, a naming system that ranks organisms by their evolutionary relationships. Within this hierarchy, living things are organized from the largest, most-inclusive group down to the smallest, least-inclusive group.
The taxonomic hierarchy is as follows, from largest to smallest.
Domain:
Domains group organisms by fundamental characteristics such as cell structure and chemistry. For example, organisms in domain Eukarya are separated from those in the Bacteria and Archaea domains based on whether their cells have a nucleus, the types of molecules found in the cell wall and membrane, and how they go about protein synthesis. (We introduce the three domains in the earlier section “
Meet Your Neighbors: Looking at Life on Earth
.”)
Kingdom:
Kingdoms group organisms based on developmental characteristics and nutritional strategy. For example, organisms in the animal kingdom (Animalia) are separated from those in the plant kingdom (Plantae) because of differences in the early development of these organisms and the fact that plants make their own food by photosynthesis, whereas animals ingest their food. (Kingdoms are most useful in domain Eukarya because they’re not well defined for the prokaryotic domains.)
Phylum:
Phyla separate organisms based on key characteristics that define the major groups within the kingdom. For example, within kingdom Plantae, flowering plants (Angiosperms) are in a different phylum than cone-bearing plants (Conifers).
Class:
Classes separate organisms based on key characteristics that define the major groups within the phylum. For example, within phylum Angiophyta, plants that have two seed leaves (dicots, class Magnoliopsida) are in a separate class than plants with one seed leaf (monocots, class Liliopsida).
Order:
Orders separate organisms based on key characteristics that define the major groups within the class. For example, within class Magnoliopsida, nutmeg plants (Magnoliales) are put in a different order than black pepper plants (Piperales) due to differences in their flower and pollen structure.
Family:
