Biology For Dummies®

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This table shows you many roots to help you decipher words you hear in biology class. Greek or Latin Root Look for words that mean and and or to help determine which probabilities to multiply ( and) and which to add ( or). The most important characteristic of a cell is that it can reproduce by dividing. If cells did not reproduce, you or any other living thing would not continue to live. Cell division is the process by which cells duplicate and replace themselves. If you did not replace your red blood cells, for example, you would have a life span only as long as that of red blood cells — a mere 120 days. Yet as humans draw more heavily upon the Earth’s resources, we’re putting stress on many other species and possibly driving them to extinction. The great lesson of biological evolution (a topic we cover in Chapter 12) is that not only do populations change over time but they’re also capable of going extinct. The challenge that humans face today is discovering ways to get what we need but still live in balance with the Earth’s various ecosystems. Getting Up Close and Personal with the Anatomy and Physiology of Animals

Circulatory system: Transports materials throughout the body. Consists of your heart, blood, and blood vessels (see Chapter 15). 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. 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. Homeostasis is the balance, or equilibrium, of the body. Regulation of all the body’s systems seeks to keep the body in homeostasis. Flowers may also have a ring of green, leaf-like structures called sepals. Sepals help protect the flower when it’s still in the bud. In some flowers, the sepals look just like the petals and help attract pollinators. Scientists call the ring of sepals in the flower the calyx.Scientists interpret the results of their experiments through deductive reasoning, using their specific observations to test their general hypothesis. When making deductive conclusions, scientists consider their original hypothesis and ask whether it could still be true in light of the new information gathered during the experiment. If so, the hypothesis can remain as a possible explanation for how things work. If not, scientists reject the hypothesis and try to come up with an alternate explanation (a new hypothesis) that could explain what they’ve seen. In the earlier worm example, the marine biologist discovers that the internal structures of the wormlike creature look very similar to another type of worm he’s familiar with. He can therefore conclude that the new animal is likely a relative of that other type of worm. Release carbon dioxide (CO 2): Cells return CO 2 to the environment as waste, which is great for the autotrophs that require CO 2 to produce the food that heterotrophs eat. (See how it’s all connected?) A stalk called the peduncle supports the flower, which may also have a swollen base called the receptacle.

Hemoglobin is an example of the other major type of proteins: globular proteins. Globular proteins serve a larger variety of functions than the fibrous proteins. For example, the globular proteins include such useful proteins as enzymes, antibodies, and transport proteins. technicalstuff The Technical Stuff icon marks extra information that isn’t necessary to understanding the material in the chapter. If you want to take your understanding of biology to a higher level, or if you just want to build your knowledge base of interesting facts, incorporate these paragraphs into your reading. If you just want the basics and don’t want to bother with nonessential information, skip them.

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Inductive reasoning uses specific observations to generate general principles, like those in a hypothesis. After fertilization of the eggs by sperm, the ovules within a flower become seeds, and the ovary becomes a fruit. Seeds protect the embryo, and fruits help scatter the seeds away from the parent plant.

remember Systems thinking is an approach that seeks to understand the whole system by looking at the connections between the parts of the system. Systems thinking is a very powerful approach for solving complex problems because it makes people widen their perspective and consider many different components that could contribute to the situation. By taking a wider view and considering the big picture, people are more likely to identify how they can change a system to solve a problem. Nervous system: Controls your body functions via electrical signals. Made up of your brain, spinal cord, and nerves (see Chapter 18).The scientific method starts when scientists notice something and ask questions like What’s that? or How does it work? just like a child might when he sees something new. Instead of traveling across the oceans to explore the world and catalog living things like the discovery scientists of 200 years ago, scientists from all over the world set out to explore the very tiny, but very complex, landscape of the 46 human chromosomes that contain the collection of all the genes found in humans. Each of the 25,000 genes they located provides information about inherited traits. The traits range from little things, such as whether you can curl your tongue or not, to truly important things, such as whether you have a genetic risk for developing breast cancer or cystic fibrosis. By finding out where genes are located, scientists can turn their attention to using this newfound information to develop hypotheses about cures and gene therapies. Designing experiments

When solving genetics problems, it pays to know what patterns to look for. The parent genotypes and offspring phenotypic ratios in this table can help you figure out what kind of inheritance is at work. Parent Genotypes Hemoglobin is a transport protein found in red blood cells: It carries oxygen around the body. A hemoglobin molecule is shaped kind of like a 3-D four-leaf clover without a stem. Each leaf of the clover represents a certain chain of protein. In the center of the clover, but touching each protein chain, lies a heme group. At the very center of a heme group is an atom of iron.

What should I know before starting biology?

How living things grow, develop, and reproduce, including how these processes are regulated by DNA, hormones, and nerve signals remember Everything an organism’s body does happens because its cells make those actions happen, whether that organism is a single-celled E. coli bacteria or a human being made up of approximately 10 trillion cells. Use deductive reasoning to decide whether your experiment supports or rejects your hypothesis and to compare your results with those of other scientists. Bryophytes are plants, such as mosses, that don’t have a vascular system and don’t produce flowers or seeds. Bryophytes also don’t have a true root system. Instead, many rely upon delicate anchoring structures called rhizoids.