Unit I

Part I Biology: The Study of Life

Chapter IBiology:The Study of LifeBy: Dr. Iis Nur Asyiah

Introduction to BiologyObjectives :Define biology.Identify possible benefits from studying biology.Summarize the characteristics of living thingsMain Idea :All living things share the characteristics of life.

The Science of lifePeople have always been curious about living thingshow many different kinds there are, where they live, what they are like, how they relate to each other, and how they behave. The concepts, principles, and theories that allow people to understand the natural environment form the core of biology, the study of life.

Predict the types of questions you would ask if you observed chimpanzee behavior.Figure 1.1

What do biologists do?Study the diversity of lifeJane Goodall, shown in Figure 1.1, studied chimpanzees in their natural environments. She studied and recorded chimpanzee reproductive habits and their aggressive nature. She learned that they use tools. Goodalls data provided a better understanding of chimpanzees, and as a result, scientists know how to best protect them.

Through your study of biology, you will come to appreciate the great diversity of life on Earth and the way all living organisms fit into the dynamic pattern of life on our planet.

BioFactsThere are approximately 200 billion stars that make up the Milky Way galaxy.Humans are 1 out of an estimated 100 million species of life on Earth.The human brain is made up of 100 billion neurons.

Research diseasesMany biologists research diseases. Questions such as What causes the disease?, How does the body fight the disease?, and How does the disease spread? often guide biologists research. Biologists worldwide are researching new medicines for such things as lowering cholesterol levels, fighting obesity, reducing the risk of heart attacks, and preventing Alzheimers disease.

Develop technologiesWhen you hear the word technology, you might think of high-speed computers, cell phones, and DVD players. However, technology is defined as the application of scientific knowledge to solve human needs and to extend human capabilities. Figure 1.3 shows how new technologya bionic handcan help someone who has lost an arm.Figure 1.3 A prosthetic bionic hand is new technologythat can help extend human capabilities.

Figure 1.3 A prosthetic bionic hand is new technology that can help extend human capabilities.

Improve agriculture Some biologists study the possibilities of genetically engineering plants to grow in poor soils or to resist insects, fungal infections, or frost damage. Other biologists research agricultural issues to improve food production to feed the worlds growing human population.

Figure 1.4 Joanne Chory, a plant biologist,researches how plants respond to light.

Preserve the environment Environmental biologists seek to prevent the extinction of animals and plants by developing ways to protect them. Some biologists study the reproductive strategies of endangered species while they are in captivity. Other biologists work in nature preserves that provide safe places for endangered species to live, reproduce, and have protection against poachers.

Biologists study the interactionsof the environmentBecause no living things, including humans, exist in isolation, the study of biology must include the investigation of living interactions. For example, learning about a population of wild rabbits would require finding out what plants they eat and what animals prey on them. The study of one living thing always involves the study of the others with which it interacts.

Apa yang akan terjadi apabila semua kucing di dunia ini mati?..............

The Characteristics of LifeHave you ever tried to define the word alive? If you were to watch a grizzly bear catch a salmon from a river, you obviously would conclude that the bear and salmon are both alive. Is fire alive? Fire moves, increases in size, has energy, and seems to reproduce, but how does fire differ from the bear and salmon?

Made of one or more cellsAll organisms are made of one or more cells. The cell is the basic unit of life. Some organisms, such as the Paramecium sp., are unicellular.

Displays organizationThe levels of organization in biological systems begin with atoms and molecules and increase in complexity. Each organized structure in an organism has a specific function.

Grows and developsGrowth results in an increase in mass. Development results in different abilities. A bullfrog tadpole grows and develops into an adult bullfrog.

Living things make more living things/Reproduces

Living things adjust to their surroundings/Responds to stimuliOrganisms live in a constant interface with their surroundings, or environment, which includes the air, water, weather, temperature, any other organisms in the area, and many other factors.

Reactions to internal and external stimuli are called responses. This cheetah responds to the need for food by chasing a gazelle. The gazelle responds by running away.

Explain How does this plant respond tostimuli to obtain food?

Requires energyEnergy is required for all life processes. Many organisms, like this squirrel, must take in food. Other organisms make their own food.

Maintains homeostasisAll organisms keep internal conditions stable by a process called homeostasis. For example, humans perspire to prevent their body temperature from rising too high.

Living things adapt and evolve

The Nature of ScienceObjectives :Explain the characteristics of science.Compare something that is scientific with something that is pseudoscientific.Describe the importance of the metric system and SI.Main idea :Science is a process based on inquiry that seeks to develop explanations.

What is science?Have you ever wondered how science is different from art, music, and writing? Science is a body of knowledge based on the study of nature.Biology is a science, as are chemistry, physics, and Earth scienceThe nature, or essential characteristic, of science is scientific inquiry

Scientific inquiry is both a creative process and a process rooted in unbiased observations and experimentation. Sometimes scientists go to extreme places to observe and experiment

This volcanologist is near molten lava flowing from Mount Etna. Lava temperatures can reach 750C.

Relies on evidence : That person probably meant that he or she had a possible explanation about something. Scientific explanations combine what is already known with consistent evidence gathered from many observations and experiments.

Expands scientific knowledge :How can you know what information is science-based? Most scientific fields are guided by research that results in a constant reevaluation of what is known.

Challenges accepted theories : Scientists welcome debate about one anothers ideas. They regularly attend conferences and meetings where they discuss new developments and findings. Often, disagreements occur among scientists. Then additional investigations and/or experiments are done to substantiate claims.

Questions results : Observations or data that are not consistent with current scientific understanding are of interest to scientists. These inconsistencies often lead to further investigations.

Tests claims : Whenever biologists engage in research, they use standard experimental procedures. Science-based information makes claims based on a large amount of data and observations obtained from unbiased investigations and carefully controlled experimentation.

Undergoes peer review : Before it is made public, science-based information is reviewed by scientists peersscientists who are working in the same field of study.Uses metric system : Scientists can repeat the work of others as part of a new experiment. Using the same system of measurements helps make this possible. Most scientists use the metric system when collecting data and performing experiments.

Section 1.3The Methods of BiologyObjectivesCompare different scientific methods.Differentiate among hypothesis, theory, and principle.

What is science?Have you ever wondered how science is different from art, music, and writing? Science is a body of knowledge based on the study of nature. Biology is a science, as are chemistry, physics, and Earth science. The nature, or essential characteristic, of science is scientific inquiry.Science is a process based on inquiry that seeks to develop explanations.

Why does rain bring out the worms?If you have ever Wondered why earthworms appear after a rain, then you have used methods like scientists use to develop experiments. Scientists use many different methods to answer questions, but all scientific inquiries share some common methods.

Scientific MethodsScientific methods are used by scientists to answer questions and solve problems. The development of the cell theory, one of the most useful theories in biological science, illustrates how the methods of science work. In 1665, Robert Hooke first observed cells in cork. He made the drawing on the right, showing what he saw.

ObservingThe first step toward scientific discovery often takes place when a scientist observes something no one has noticed before. After Hookes discovery, other scientists observed cells in a variety of organisms.

B. Making a hypothesis A hypothesis is a testable explanation or answer to a question. In 1824, Ren Dutrochet hypothesized that cells are the basic unit of life. A scientific hypothesis must have two important qualitiesIt must be testableIt must be falsifiable

Collecting data Data can support or disprove a hypothesis. Over the years, scientists who used microscopes to examine organisms found that cells are always present.

D. Publishing results Results of an investigation are useful only if they are made available to other scientists for a peer review. Many scientists published their observations of cells in the scientific literature. Scientists will analyze the procedure, examine the evidence, identify faulty reasoning, point out statements that go beyond the evidence, and suggest alternative explanations for the same observations.

E. Forming a theory A theory is a hypothesis that is supported by a large body of scientific evidence. By 1839, many scientific observations supported the hypothesis that cells are fundamental to life. The hypothesis became a theory.

F. Developing new hypotheses A new theory may prompt scientists to ask new questions or form additional hypotheses. In 1833, Robert Brown hypothesized that the nucleus is an important control center of the cell.

G. Revising the theory Theories are revised as new information is gathered. The cell theory gave biologists a start for exploring the basic structure and function of all life. Important discoveries, including the discovery of DNA, have resulted.

Scientific MethodsObservationHypothesisExperimentTheory

REVIEWWhat is biology?Living things abound almost everywhere on Earthin deep ocean trenches, atop the highest mountains, in dry deserts, and in wet tropical forests. Biology is the study of living organisms and the interactions among them. Biologists use a variety of scientific methods to study the details of life.

Soal quiz

Why is energy required for living things? How do living things obtain energy?