Biology Workbook For Dummies
Overview
Get a feel for biology with hands-on activities
Biology Workbook For Dummies is a practical resource that provides you with activities to help you better understand concepts in biology. Covering all the topics required in high school and college biology classes, this workbook gives you the confidence you need to ace the test and get the grade you need. Physiology, ecology, evolution, genetics, and cell biology are all covered, and you can work your way through each one or pick and choose the topics where you could use a little extra help. This updated edition is full of new workbook problems, updated study questions and exercises, and fresh real-world examples that bring even the tough concepts to life.
- Get extra practice in biology with activities, questions, and exercises
- Study evolution, genetics, cell biology, and other topics in required biology classes
- Pass your tests and improve your score in high school or college biology class
- Demystify confusing concepts and get clear explanations of every idea
Great as a companion to Biology For Dummies or all on its own, Biology Workbook For Dummies is your practice supplement of choice.
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About The Author
René Fester Kratz is a biology and global health instructor at Everett Community College and holds a Ph.D. in Botany from the University of Washington. Kratz is the author of Molecular & Cell Biology For Dummies 2nd Edition, Biology For Dummies 2nd Edition, Biology Essentials For Dummies, and Botany For Dummies.
Sample Chapters
biology workbook for dummies
CHEAT SHEET
Biology is the study of life, from tiny bacteria to giant redwood trees to human beings. Understanding biology begins with knowing some of the basics, such as eukaryotic cell structure and common Latin and Greek roots that will help you decipher the sometimes-tough vocabulary.Biology basics: Important components of eukaryotic cellsFor biology students, knowing the components of eukaryotic cells and how they work is fundamental to understanding how organisms function.
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When a neuron is inactive, just waiting for a nerve impulse to come along, the neuron is polarized — that is, the cytoplasm inside the cell has a negative electrical charge, and the fluid outside the cell has a positive charge. This separation of charge sets up conditions for the neuron to respond, just like a separation of charge in a battery sets up conditions that allow a battery to provide electricity.
Your adaptive immunity gets its name because it adapts and changes, or adapts, as you go through life and are exposed to specific microbes that your innate defenses can’t fight. Your body’s innate defenses are incredible, and they prevent infection by most of the microbes that you encounter in your life.
But every now and then, a microbe comes along that gets around your innate defenses and into your body.
Every animal alive possesses a circulatory system that’s in charge of bringing nutrients to cells and removing wastes so they don’t cause disease. While they move fluids around the body, circulatory systems also help out with other tasks by
Delivering oxygen to cells and picking up carbon dioxide
Distributing hormones to cells
Maintaining body temperature by transporting heat
Transporting cells to fight infection
Animals have two types of circulatory systems:
In open circulatory systems, the animal’s heart pumps a bloodlike fluid called hemolymph through open-ended vessels into a chamber called the hemocoel, where it directly bathes the cells.
All animals need to break down food molecules into smaller pieces so they can circulate them around their bodies to all their cells. Their cells take in small food molecules and use them as material for growth or as a source of energy.
Four main events occur from the moment food enters an animal’s body until the time the animal releases its wastes:
Ingestion occurs when an animal takes food into its digestive tract.
Every type of locomotion, movement from one place to another, requires animals to use energy to overcome the forces of friction and gravity that would otherwise hold them to Earth.
Friction is the force that pushes back on any movement of two objects in contact with each other. The force of friction due to movement through air or water is called resistance.
Respiration is the exchange of life-sustaining gases, such as oxygen, between an animal and its environment. Gas exchange occurs by diffusion, moving necessary gases like oxygen into animals and taking away waste gases like carbon dioxide. Although animals have different ways of moving gases in and out of their bodies, gas exchange between the animal and its environment occurs across a moist surface.
Joints are structures where two bones are attached. Movable or synovial joints allow bones to move relative to each other. In many areas of the body, strong, fibrous connective tissues called ligaments stabilize joints.
Three common types of movable joints enable most of the movements of animals:
Ball-and-socket joints allow movement in many directions.
Life thrives in every environment on Earth, and each of those environments is its own ecosystem, essentially a little machine made up of living and nonliving parts that interact with one another in a particular environment. An ecosystem can be very large, like the open ocean, or very small, like the ecosystem inside the digestive system of an ant.
Biology
For biology students, knowing the components of eukaryotic cells and how they work is fundamental to understanding how organisms function. This table provides an overview of the most important eukaryotic cell structures and functions and how to recognize them.
Structure
Function
How to Recognize
Cell wall
Rigid boundary around some cells
Outermost boundary in plant, algal, fungal, and bacterial
cells.
Not all the organisms in a given biological community are the same. In fact, they’re often members of different species (organisms that can’t sexually reproduce together and produce fertile offspring). Yet these organisms must interact with one another as they go about their daily business of finding what they need to survive.
Biology
Organisms in biological ecosystems connect to one another through their need for matter as well as energy. Every organism needs molecules like proteins, carbohydrates, and fats to provide the raw building materials for their cells.
One of the most fascinating facts about Earth is that almost all the matter on the planet today has been here since Earth first formed.
The two most extreme outcomes of natural selection for species are extinction and speciation. Natural selection may cause populations of species to change, but exactly how they change depends on the specific selective pressures at a given time.
Individuals within a population may evolve to be more similar to or more different from one another depending on the specific circumstances and selection pressures.
You can interpret the degree of relationship between two organisms by looking at their positions on a phylogenetic tree.
Phylogenetic trees not only show how closely related organisms are but also help map out the evolutionary history, or phylogeny, of life on Earth.
Based on structural, cellular, biochemical, and genetic characteristics, biologists classify life on Earth into groups that reflect the planet’s evolutionary history.
Population ecology is the branch of biology that studies the structures of populations and how they change. The unique thing about population ecologists is that they study the relationships within ecosystems by studying the properties of populations rather than individuals:
Population size is the total number of individuals in the population.
Pulmonary circulation, the first pathway of your two-circuit circulatory system, brings blood to your lungs for oxygenation. Following is a rundown of how blood moves during pulmonary circulation.
Deoxygenated blood from your body enters the right atrium of your heart through the superior vena cava and the inferior vena cava.
Biologists draw phylogenetic trees to show the relationships of organisms within a group, much like you’d draw a family tree to show the relationships among your parents, grandparents, and other family members.
The more characteristics two organisms have in common with each other, the more closely related they are.
Systemic circulation brings oxygenated blood around to all your body’s cells. Here is a description of how blood moves through this pathway (see the figure):
The pulmonary veins push oxygenated blood into the left atrium.
When the left atrium relaxes, the oxygenated blood drains into the left ventricle through the left AV valve.
Muscle tissues are extremely important to your body — and not just because they help you look good at the pool. Muscles do many things to keep you alive and going strong:
Muscles allow you to stand upright. Your muscles contract so that you can push against the surface of the Earth, defying gravity to stand upright.
Biology is the study of life, from tiny bacteria to giant redwood trees to human beings. Understanding biology begins with knowing some of the basics, such as eukaryotic cell structure and common Latin and Greek roots that will help you decipher the sometimes-tough vocabulary.Biology basics: Important components of eukaryotic cellsFor biology students, knowing the components of eukaryotic cells and how they work is fundamental to understanding how organisms function.
Population dynamics are changes in population density over time or in a particular area. Primarily, populations increase because of births (natality) and decrease because of deaths (mortality).
The rate at which a population increases (r) depends on the relative number of births (B) and deaths (D) during a particular time interval:
r = B – D
To figure out how many individuals are added to or subtracted from a population (in other words, how much a population grows or decreases), you also have to take into account the size of the population itself.
Biology
Students in introductory biology classes typically have to learn more new vocabulary words than students taking a foreign language! The good news is that many science vocabulary words use the same Greek and Latin roots. When you know these roots, you can figure out what a word means, even if you've never heard it before.
At the heart of a revolution in our understanding of life on Earth is the ability to go to the source — DNA — and directly read the genetic code. Over the past 30 years, this revolution has been taking place in the sciences of biology and medicine.
You’ve seen evidence of this revolution if you watch detective shows or read books about crime that feature forensic science and DNA evidence.
Oogenesis (the egg-producing process), which includes the ovarian and menstrual cycles, begins very early in the life of a human female, when she’s still a developing fetus! In fact, a human female is born with all the eggs she’ll ever have.
However, the eggs aren’t quite finished, because cell division pauses early in the first half of meiosis.
In addition to the nervous system’s electrical signals, animals also regulate their bodies with chemical messengers called hormones. Endocrine glands produce the hormones and then release them into the blood to travel through the body until they reach their target cells, the cells that respond to the hormone. For a cell to respond to a particular hormone, it must have receptors for that hormone.
The figure here represents biologists’ current understanding of the tree of life — the phylogenetic tree that shows relationships among all organisms on Earth. Each of the main branches on the family tree represents a unique type of life on Earth, which biologists place into categories they call domains. Within each domain, biologists create smaller categories that represent groups of related organisms.
DNA sequencing, which determines the order of nucleotides in a DNA strand, allows scientists to read the genetic code so they can study the normal versions of genes. It also allows them to make comparisons between normal versions of a gene and disease-causing versions of a gene.
After they know the order of nucleotides in both versions of a gene, they can identify which changes in the gene cause the disease.
Biology
Scientists use gel electrophoresis to separate molecules based on their size and electrical charge. Gel electrophoresis can separate fragments of DNA that were cut with restriction enzymes, creating a visual map of fragment size that’s easy to interpret. Or scientists may use gel electrophoresis to separate a protein they want to study from other proteins in a cell.
Several processes work together to transport water from where a plant absorbs it (the roots) upward through the rest of its body. To understand how these processes work, you first need to know one key feature of water: Water molecules tend to stick together, literally.
Water molecules are attracted to one another and to surfaces by weak electrical attractions.
Plant cells communicate with one another via messengers called hormones, chemical signals produced by one type of cell that travel to target cells and cause changes in their growth or development. Plant hormones control many familiar plant behaviors.
Six categories of hormones control plant growth and development:
Auxins stimulate the elongation of cells in the plant stem and trigger phototropism (the growth of plants toward light).
Plants use a special tissue called phloem to transports sap — a sticky solution that contains sugars, water, minerals, amino acids, and plant hormones. Sap moves through phloem via translocation, the transport of dissolved materials in a plant. Unlike the xylem, which can only carry water upward, phloem carries sap upward and downward, from sugar sources to sugar sinks:
Sugar sources are plant organs such as leaves that produce sugars.
Plants get all the carbon, hydrogen, and oxygen they need from carbon dioxide and water, which they use to build carbohydrates during photosynthesis. To build other kinds of molecules they also need elements like nitrogen, phosphorous, and sulfur. Plants get these as well as other elements from the soil.
Just like you do, plants build their cells from carbohydrates, proteins, lipids, and nucleic acids.
Biology
Scientists use restriction enzymes to cut DNA into smaller pieces so they can analyze and manipulate DNA more easily. Each restriction enzyme recognizes and can attach to a certain sequence on DNA called a restriction site.
You can think of restriction enzymes as little molecular scissors that slide along the DNA and cut the sugar-phosphate backbone wherever they find their restriction site.
Biological evolution refers to the change of living things over time. Charles Darwin introduced the world to this concept in his 1859 work, On the Origin of Species. In this book, Darwin proposed that living things descend from their ancestors but that they can change over time.
Darwin concluded that biological evolution occurs as a result of natural selection, which is the theory that, in any given generation, some individuals are more likely to survive and reproduce than others.
Fertilization, the joining of sperm and egg, typically occurs in the fallopian tube, after sperm have made the long swim up through the vagina, past the cervix, and through the uterus. Fertilization brings together the chromosomes from each parent, creating the first cell, or zygote, of the new human.
Because a human egg lives no longer than 24 hours after ovulation and human sperm live no longer than 72 hours, intercourse that occurs in the three-day period prior to ovulation or within the day after ovulation is the only chance of fertilization during a given month.
Biology
Knowledge of the organ systems involved in human sexual reproduction helps you learn about the reproduction process. The following figure illustrates the male reproductive system:
The egg-shaped male gonads, called testes, rest in a sac called the scrotum. Sperm don’t develop normally at the human body’s core temperature, so keeping them cooler outside the body allows normal development.
You’re usually unaware of all the microbes roaming the world because you can’t see them and because your innate immunity keeps most of them from bothering you. Innate immunity is the built-in immunity that your body has. Like the walls of a fortress, your innate defenses can repel all attackers (meaning they’re not specifically targeted for one particular pathogen).
Microbes are things like bacteria and viruses that are too small to see with the naked eye. They exist on every surface and in every environment on Earth. They’re in the air, in the water, in the soil — even in your body.
Most microbes can’t hurt you, and many of them are beneficial to the environment or your body.
Biology
The heart and circulatory system of a human, as well as some other mammals, are complex. These large animals need to have a higher blood pressure to push the blood throughout their entire bodies. This need results in a two-circuit circulatory system, a system that has two distinct pathways:
One pathway is for pulmonary circulation, which first delivers deoxygenated blood to the lungs so it can become oxygenated and then delivers oxygenated blood back to the heart.
Animals are the only living things on Earth with complex nervous systems that first receive and interpret sensory signals from the environment and then send out messages to direct the animal’s response. The complexity of an animal’s nervous system depends on its lifestyle and body plan.
Animals whose bodies don’t have a defined head or tail have nerve nets, which are weblike arrangements of nerve cells that extend throughout the body.
Neurons are cells that form the core of nervous systems because they have the ability to receive and transmit signals. Neurons have a unique elongated shape and consist of three main parts:
Nerve cell body: The rounded part of the neuron. It contains typical eukaryotic cell components like the nucleus, organelles, and the endomembrane system.
Plants are very successful organisms, growing in almost every environment on Earth. Part of their success is due to the fact that they can reproduce both asexually and sexually.
When plants reproduce asexually, they use mitosis to produce offspring that are genetically identical to the parent plant. The advantage of asexual reproduction is that it allows successful organisms to reproduce quickly.
Skeletons give muscles something to pull against; support the body’s weight; store minerals like calcium and phosphorus; and produce blood cells in the bone marrow. However, not all animals have the same type of skeleton. Following are the three different kinds of skeletons you may see in your study of biology:
Hydrostatic skeletons are basically chambers filled with water.
Science classes, like biology, may be among the most challenging classes you'll ever take. Getting an A in biology means looking at some of the major issues you'll face and having tips for dealing with them.
Plan for biology study time
One of the reasons that science classes are so challenging is that they ask you to look at things you've never looked at before.
Your heart is an impressive little organ. Even though it’s only as big as a clenched adult fist, it pumps 5 liters of blood throughout your body 70 times a minute. Your heart never stops working from the time it starts beating in the embryo until the moment you die. It doesn’t even get an entire second to rest.
Humans have a complete digestive tract: Food enters at one end and wastes exit from the opposite end. Digestion begins in the mouth and continues as food moves through your system:
Digestion in the mouth occurs by both chemical and mechanical means.
Chewing, or mastication, mechanically breaks food into smaller pieces.
Like most organs in the human body, the function of a kidney is closely tied to its structure. The outer covering on each kidney, called the capsule, is made of stretchy collagen fibers that help anchor your kidneys. Under the capsule, each kidney has three distinct areas:
The renal cortex, which is the outer layer.
Like animals, plants are made of cells and tissues, and those tissues form organs, such as leaves and flowers, that are specialized for different functions. Two basic organ systems exist in plants:
The shoot system, located above ground, helps plants capture energy from the sun for photosynthesis. Organs found within the shoot system include leaves, stems, cones, and flowers.
The female reproductive system produces eggs and supports the developing fetus. The reproductive process begins when a sperm cell from a male joins with an egg cell from a female in a process that scientists call fertilization.
The figure illustrates the structures of the female reproductive system.
The female gonads are oval, lumpy-looking structures called ovaries.
Your body releases wastes that are filtered from your blood and tissue fluids as part of your urine. In particular, urine helps you flush out nitrogenous wastes — unnecessary, excess materials containing nitrogen that result from the breakdown of proteins and nucleic acids.
Also, because your urinary system releases fluid from your body, it plays an important role in maintaining the proper fluid balance in the body.
Plant organs are made of plant tissues, which are made of plant cells. All plants have tissues, but not all plants possess all three of the following types of tissues:
Dermal tissue: Consisting primarily of epidermal cells, dermal tissue covers the entire surface of a plant.
Ground tissue: This tissue type makes up most of a plant’s body and contains three types of cells:
Parenchyma cells are the most common ground tissue cells.
Biology
Since Darwin first proposed his ideas about biological evolution and natural selection, different lines of research from many different branches of science have produced evidence supporting his belief that biological evolution occurs in part because of natural selection.
Because a great amount of data supports the idea of biological evolution through natural selection, and because no scientific evidence has yet been found to prove this idea false, this idea is considered a scientific theory.
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