Biology For Dummies book cover

Biology For Dummies

Overview

The ultimate guide to understanding biology

Have you ever wondered how the food you eat becomes the energy your body needs to keep going? The theory of evolution says that humans and chimps descended from a common ancestor, but does it tell us how and why? We humans are insatiably curious creatures who can't help wondering how things work—starting with our own bodies. Wouldn't it be great to have a single source of quick answers to all our questions about how living things work? Now there is.

From molecules to animals, cells to ecosystems, Biology For Dummies answers all your questions about how living things work. Written in plain English and packed with dozens of enlightening illustrations, this reference guide covers the most recent developments and discoveries in evolutionary, reproductive, and ecological biology. It's also complemented with lots of practical, up-to-date examples to bring the information to life.

  • Discover how living things work
  • Think like a biologist and use scientific methods
  • Understand lifecycle processes

Whether you're enrolled in a biology class or just want to know more about this fascinating and ever-evolving field of study, Biology For Dummies will help you unlock the mysteries of how life works.

The ultimate guide to understanding biology

Have you ever wondered how the food you eat becomes the energy your body needs to keep going? The theory of evolution says that humans and chimps descended from a common ancestor, but does it tell us how and why? We humans are insatiably curious creatures who can't help wondering how things work—starting with our own bodies. Wouldn't it be great to have a single source of quick answers to all our questions about how living things work? Now there is.

From molecules to animals, cells to ecosystems, Biology For Dummies answers all your questions about how living things work. Written in plain

English and packed with dozens of enlightening illustrations, this reference guide covers the most recent developments and discoveries in evolutionary, reproductive, and ecological biology. It's also complemented with lots of practical, up-to-date examples to bring the information to life.
  • Discover how living things work
  • Think like a biologist and use scientific methods
  • Understand lifecycle processes

Whether you're enrolled in a biology class or just want to know more about this fascinating and ever-evolving field of study, Biology For Dummies will help you unlock the mysteries of how life works.

Biology For Dummies Cheat Sheet

Biology is the study of the living world. All living things share certain common properties:

  • They are made of cells that contain DNA.
  • They maintain order inside their cells and bodies.
  • They regulate their systems.
  • They respond to signals in the environment.
  • They transfer energy between themselves and their environment.
  • They grow and develop; they reproduce.
  • They have traits that have evolved over time.

Articles From The Book

27 results

Biology Articles

Five Hormones that Control Plant Growth & Development

Plant cells communicate with each other via messengers called hormones, chemical signals produced by cells that act on target cells to control their growth or development. Plant hormones control many of the plant behaviors you’re used to seeing, such as the ripening of fruit, the growth of shoots upward and roots downward, the growth of plants toward the light, the dropping of leaves in the fall, and the growth and flowering of plants at particular times of the year. Five categories of hormones control plant growth and development:

  • Auxins stimulate the elongation of cells in the plant stem and phototropism (the growth of plants toward light). If a plant receives equal light on all sides, its stem grows straight. If light is uneven, then auxin moves toward the darker side of the plant. This may seem backward, but when the shady side of the stem grows, the stem, in its crookedness, actually bends toward the light. This action keeps the leaves toward the light so photosynthesis can continue.
  • Gibberellins promote both cell division and cell elongation, causing shoots to elongate so plants can grow taller and leaves can grow bigger. They also signal buds and seeds to begin growing in the spring.
  • Cytokinins stimulate cell division, promote leaf expansion, and slow down the aging of leaves. Florists actually use them to help make cut flowers last longer.
  • Abscisic acid inhibits cell growth and can help prevent water loss by triggering stomates to close. Plant nurseries use abscisic acid to keep plants dormant during shipping.
  • Ethylene stimulates the ripening of fruit and signals deciduous trees to drop their leaves in the fall. Fruit growers use ethylene to partially ripen fruit for sale.

Some of the flavor-making processes that occur in fruits happen while the fruits are still on the plant. So, even though ethylene can trigger some parts of ripening, like softening after a fruit has been picked, fruit that’s picked unripe doesn’t taste as good as fruit that has ripened on the plant. That’s why you can buy a big, beautiful tomato at the grocery store and take it home only to discover that it doesn’t have much flavor — it was probably picked unripe and then treated with ethylene.

If you have houseplants that are growing in bent shapes toward the window, you’re seeing the effect of the hormone auxin at work. The auxin is collecting on the shady side of your plants’ stems, and those cells are growing longer, pushing the stems toward the light. To keep your plants evenly shaped, rotate them occasionally.

If your plants are growing really long and thin, they may not have enough light in the place you put them. If all parts of the stem are too shaded, the auxin will make all sides of the stems grow long and thin. This can make the plants very fragile and they may not have enough light for photosynthesis. If they seem yellowish, that’s another clue.

Biology Articles

10 Ways Biology Affects Your Life

Sometimes science seems like something that happens in a lab somewhere far removed from everyday life. That may be, but the effects of scientific research have a huge impact on your day-to-day existence, from the food you eat to the energy that powers your home. Following is a rundown of ten important ways that biology affects your life. Most are good; others aren’t so good. Either way, you just may be surprised by a couple of them.

Keeping you fed

First off, if plants didn’t produce their own food, you wouldn’t have anything to eat — period. So you can thank the process of photosynthesis the next time you sit down to eat. Just consider a slice of cheese pizza: You use grains from wheat plants to make flour for the crust, fruits from tomato plants for the sauce, and milk from a cow to make the cheese. The cow is not a plant, but how does it make milk? With the food molecules it gets from eating plants, of course. Everything you eat, no matter how complicated, can be traced back to the food makers such as plants. Without the raw material they provide, nothing else could live on planet Earth.

Putting microbial enzymes to work

Microbes aren’t just for making foods; they have a wide variety of industrial applications too. Manufacturers put bacterial enzymes in laundry detergent to help break down greasy stains and in meat tenderizers to help break down proteins in meats. If you take vitamin C, chances are that vitamin was produced by a fungus. If you drink a protein shake regularly, the amino acids in that shake probably also came from bacteria. So you see, not all microbes are to be feared. Some of them actually improve your life by simplifying tasks and keeping you healthy.

Designing genes

The food you eat could very likely contain genetically modified organisms (GMOs) — living things whose genes have been altered by scientists in order to give them useful traits. For example, crop plants may be engineered to better resist pests, and animals may be treated with hormones to increase their growth or milk production. Some people object to the idea of GMOs in their diets, but genetic modification of organisms has enabled some amazing health breakthroughs. If you know someone who takes insulin to treat diabetes, that insulin is made by bacteria that scientists engineered to contain the human gene for insulin.

Powering the planet

Although people are starting to turn to renewable sources of energy, most of the world still runs on fossil fuels such as oil and coal. The word fossil may give you a clue that these fuels are the remnants of living things from long ago. Way back in the Carboniferous period, about 350 million years ago, green algae, plants, and bacteria used photosynthesis to harvest energy from the sun and transform it into the chemical energy stored in their cells. When these living things died, they were deposited in such a way that their energy-rich remains converted into coal, natural gas, and oil. These ancient energy reserves powered the Industrial Revolution, allowing people to grow their cities and develop new technologies for transportation, manufacturing, and communication. Unfortunately, these advances came with a cost that wasn’t fully recognized until recently. When people burn carbon-containing molecules from fossil fuels, they produce carbon dioxide as waste. And carbon dioxide is an important greenhouse gas, a gas that traps heat in our atmosphere. In part due to our use of fossil fuels, the Earth is warming, which is already affecting the survival and distribution of life on Earth. Plus, people are now facing the fact that our reserves of fossil fuels won’t last forever. Maybe one solution to both of these problems lies in mimicking the green organisms that stockpiled this energy in the first place — people could act like plants and go solar!

Causing and treating infectious disease

Whenever you get sick from an infectious disease, such as a cold or strep throat, you’re dealing with the reproduction of an alien invader. Your immune system springs into action, activating the cells necessary to fight the invasion and keep the infectious virus or bacteria from replicating itself any further. Also, whenever you take an antibiotic, you’re taking a medicine made by an organism such as a fungus or a bacterium. And when you get a vaccine, you’re getting an injection of dead or weakened pathogens so that you can train your immune system to fight them should the real thing ever infect you.

Staying alive

Scientists are working with cells, the smallest unit of life, to come up with new therapies to help people with organ failure and devastating injuries. Stem cells, which have the potential to become any kind of cell, have the most potential for this research. Scientists working on ways to coax cells to grow into new organs in the lab were recently able to get human cells to grow into an organized structure that looked like an immature heart and that started beating when they gave it some electricity. If scientists can perfect these techniques, they could someday grow organs for people from their own stem cells, which means the patient wouldn’t reject the transplant. In another amazing experiment, scientists injected stem cells into the spine of a young man who was completely paralyzed, enabling him to regain the use of his arms and hands.

Cells are the smallest living component of your body, and they can do amazing things. Every minute of every day, your cells are quietly working away, digesting your food, sending signals that control your responses, transporting oxygen around your body, contracting so you can move, and making all of your other bodily processes happen. If your cells weren’t functioning, your tissues, organs, and organ systems wouldn’t be either.

Providing you with clean water

You have wetlands to thank for the clean water you enjoy. Wetlands are areas that are saturated by water most of the time. They act like natural sponges, holding onto water and slowly filtering it around the plants that live there. As water slowly filters through wetlands, plants and microorganisms have time to absorb human wastes such as fertilizers and sewage, cleaning the water and making it safer for humans and other animals to consume. All life on Earth needs water — clean, fresh water — in order to be healthy, so wetlands are pretty important to your quality of life. Unfortunately, wetlands are under incredible pressure from development and oil exploration, and they’re disappearing at a rapid rate. Another way living things help keep water clean is through sewage treatment. Bacteria break down the organic matter in sewage, helping to clean the water before it’s released back into the environment.

Changing physically and mentally

Chances are that at some point in your life you either were or will be “ruled” by your hormones. Case in point: You meet someone you’re attracted to, signals cause hormones to be released, and suddenly your conscious mind isn’t making all the decisions. If that example doesn’t convince you of the power of hormones, just think back to puberty. During that time, your body went through an incredible transformation based solely on the signals from these potent chemical messengers.

Creating antibiotic-resistant bacteria

The populations of living things around us are constantly changing, or evolving, in response to the environment. We probably notice this most when the changes are a threat to our health and well-being. For example, most people today have heard stories about dangerous bacteria and viruses. This includes bacteria like MRSA (which stands for methicillin-resistant Staphylococcus aureus), which can’t be killed with most antibiotics. Where do antibiotic-resistant bacteria come from? The answer lies in the idea of natural selection, or survival of the fittest. Bacteria reproduce very quickly, and little changes in the traits of individuals occur with each generation so that even all the bacteria of one species aren’t the same as each other. When people use antibiotics, the susceptible bacteria die first, leaving behind the most resistant cells. These resistant cells multiply and take over the available space. As this scenario repeats over time, populations of bacteria eventually become super-resistant to antibiotics, explaining why sometimes doctors don’t have the drugs to help people who are infected with an antibiotic-resistant bacteria For the first time in a long time, people can die from an infection simply because doctors can’t kill the bacteria.

Facing extinction

Perhaps you don’t think about extinction much, but it’s something worth being aware of. If you need an example, consider the case of polar bears. As global temperatures rise, the polar ice is melting, leaving polar bears with less and less habitat. Not quite so noticeable, but also endangered, are 1,900 other species of plants and animals.

As humans convert more land and resources to their own uses, less and less habitat is available for the other organisms on Earth. Each species needs certain conditions and resources to thrive, and the sheer number of humans on Earth is threatening to overwhelm many ecosystems. That spells bad news for humans because we depend upon the health of ecosystems for our own survival.

Biology Articles

10 Great Biology Discoveries

Get ready to dive in to ten of the most important biology discoveries to date. These are listed in no particular order because they’ve all made a significant impact on the advancement of biology as a science and increased what people know and understand about the living world.

Seeing the unseen

Before 1675, people believed the only living things that existed were the ones they could see. That year, a Dutch cloth merchant named Antony van Leeuwenhoek discovered the microbial world by peering through a homemade microscope. Van Leeuwenhoek was the first person to see bacteria, which he described as little animals that moved about here, there, and everywhere. His discovery of a previously unseen universe not only turned people’s worldviews inside out but also laid the foundation for the understanding that microbes cause disease.

Discovering penicillin, the first antibiotic

People had very few tools to combat bacterial infections until Alexander Fleming discovered the antibacterial properties of penicillin in 1928. Fleming was studying a strain of staphylococcus bacteria when some of his petri dishes became contaminated with Penicillium mold. To Fleming’s surprise, wherever the Penicillium grew on the petri dish, the mold inhibited the growth of the staphylococcus bacteria. The compound penicillin was purified from the mold and first used to treat infections in soldiers during World War II. Soon after the war, the “miracle drug” was used to treat infections in the general public, and the race to discover additional antibiotics was on.

Protecting people from smallpox

Would you believe that the idea of inoculating people against diseases such as smallpox, measles, and mumps originated in ancient China? Healers there ground up scabs taken from a smallpox survivor into a powder and blew this dust into the nostrils of their patients. Gross as this may sound, these ancient healers were actually inoculating their patients to help prevent the spread of the disease. This practice laid the foundation for the later work of Dr. Edward Jenner, who developed the first vaccine against smallpox, in 1796. The smallpox vaccine was so effective that doctors were able to totally eradicate this disease from the human population. Imagine that: a disease that killed millions of people completely gone. (And now, using the same strategy, we’re very close to eradicating polio!)

Defining DNA structure

James Watson and Francis Crick figured out how a code could be captured in the structure of DNA molecules, opening the door to an understanding of how DNA carries the blueprints for proteins. They proposed that DNA is made of two nucleotide chains running in opposite directions and held together by hydrogen bonds between the nitrogenous bases. Using metal plates to represent the bases, they built a giant model of DNA that was accepted as correct almost immediately.

Finding and fighting defective genes

On August 24, 1989, scientists announced their discovery of the first known cause of a genetic disease: They found a tiny deletion from a gene on Chromosome 7 that resulted in the deadly genetic disease cystic fibrosis. This identification of a genetic defect, and the realization that this defect causes a disease, opened the floodgates of genetic research Since that fateful day, the genes for other diseases, such as Huntington’s disease, inherited forms of breast cancer, sickle cell anemia, Down syndrome, Tay-Sachs disease, hemophilia, and muscular dystrophy, have been found. Genetic tests for these diseases are available to detect whether an unborn baby has a defective gene or whether two potential parents would likely produce an affected baby. And knowing what causes the diseases enables researchers to focus on ways to possibly cure the diseases.

Discovering modern genetic principles

Gregor Mendel, a mid-19th century Austrian monk, used pea plants to perform the fundamental studies of heredity that serve as the basis for genetic concepts to this day. Because pea plants have a number of readily observable traits — smooth peas versus wrinkled peas, tall plants versus short plants, and so on — Mendel was able to observe the results of cross-pollinating and growing various varieties of pea plants. Through his experiments, Mendel was able to establish that genetic factors are passed from parents to offspring and remain unchanged in the offspring so that they can be passed on again to the next generation. Although his work was done before the discovery of DNA and chromosomes, the genetic principles of dominance, segregation, and independent assortment that Mendel originally defined are still used to this day.

Evolving the theory of natural selection

Charles Darwin’s study of giant tortoises and finches on the Galapagos Islands led to his famous theory of natural selection (also known as “survival of the fittest”), which he published in his 1859 book titled On the Origin of Species. The main point of Darwin’s theory is that organisms with traits that are better suited to the conditions in which they live are more likely to survive and reproduce, passing on their traits to future generations. These better-suited variations tend to thrive in the given area, whereas less-suited variations of the same species either don’t do as well or just die off. Thus, over time, the traits seen in a population of organisms in a given area can change. The importance of Darwin’s theory of natural selection can be seen today in the evolution of antibiotic-resistant strains of bacteria.

Formulating cell theory

In 1839, zoologist Theodor Schwann and botanist Matthias Schleiden were talking at a dinner party about their research. As Schleiden described the plant cells he’d been studying, Schwann was struck by their similarity to animal cells. The similarity between the two types of cells led to the formation of cell theory, which consists of three main ideas:
  • All living things are made of cells.
  • The cell is the smallest unit of living things.
  • All cells come from preexisting cells.

Amplifying DNA with PCR

In 1983, Kary Mullis discovered the polymerase chain reaction (PCR), a process that allows scientists to make numerous copies of DNA molecules that they can then study. Today, PCR is used for
  • Making lots of DNA for sequencing
  • Finding and analyzing DNA from very small samples for use in forensics
  • Detecting the presence of disease-causing microbes in human samples
  • Producing numerous copies of genes for genetic engineering

Editing DNA with CRISPR

French microbiologist Emmanuelle Charpentier was intrigued by a strangely repetitive piece of DNA called CRISPR that bacteria use to defend themselves against viruses. Her work led to a breakthrough in how molecules of RNA inside the bacterium Streptococcus pyogenes interacted with this piece of DNA. Then, Charpentier teamed up with American biologist Jennifer Doudna and the two scientists figured out how the RNA, DNA, and a protein called cas9 work to create a very targeted gene-editing system in the bacteria. The bacteria use this gene-editing system to keep a copy of viral DNA codes so they can defend themselves against future encounters with viruses. That’s very cool, but the real reason this discovery makes this list is because scientists all over the world are now exploring how they can use this bacterial gene-editing system to edit the genes of other species. The possibilities are vast (and some are scary), but a major hope is that scientists will be able to use this system to treat genetic diseases by replacing defective genes with normal ones. Although this discovery is very recent, we’re sure that we’ll be hearing lots more about CRISPR in the future.