Science assignment

Chapter Review

Summary

Section 1.1 Biology is the scientific study of life. We know about only a fraction of the organisms that live on Earth, in part because we have explored only a fraction of its inhabited regions.

Section 1.2 Biologists think about life at different levels of organization, with new properties emerging at successively higher levels. All matter consists of atoms, which bond together to form molecules. Organisms are individuals that consist of one or more cells, the organizational level at which life emerges. A population is a group of interbreeding individuals of a species in a given area; a community is all populations of all species in a given area. An ecosystem is a community interacting with its environment. The biosphere includes all regions of Earth that hold life.

Section 1.3 Life has underlying unity in that all living things have similar characteristics:

1. All organisms require energy and nutrients to sustain themselves. Producers harvest energy from the environment to make their own food by processes such as photosynthesis; consumers ingest other organisms, or their wastes or remains.

2. Organisms keep the conditions in their internal environment within ranges that their cells tolerate—a process called homeostasis.

3. DNA contains information that guides an organism’s growth, development, and reproduction.

The passage of DNA from parents to offspring is inheritance.

Section 1.4 The many types of organisms that currently exist on Earth differ greatly in details of body form and function. Biodiversity is the sum of differences among living things. Bacteria and archaea are prokaryotes, single-celled organisms whose DNA is not contained within a nucleus. The DNA of single-celled or multicelled eukaryotes (protists, plants, fungi, and animals) is contained within a nucleus.

Each species has a two-part name. The first part is the genus name. When combined with the specific epithet, it designates the particular species. With taxonomy, species are ranked into ever more inclusive taxa on the basis of shared traits.

Section 1.5 Critical thinking, the self-directed act of judging the quality of information as one learns, is an important part of science. Generally, a researcher observes something in nature, forms a hypothesis (testable explanation) for it, then makes a prediction about what might occur if the hypothesis is correct. Predictions are tested with observations, experiments, or both. Experiments typically are performed on an experimental group as compared with a control group, and sometimes on model systems. Conclusions are drawn from data. A hypothesis that is not consistent with data is modified or discarded. The scientific method consists of making, testing, and evaluating hypotheses, and sharing results with the scientific community.

Biological systems are usually influenced by many interacting variables. Research approaches differ, but experiments are designed in a consistent way, in order to study a single cause-and-effect relationship in a complex natural system.

Section 1.6 Small sample size increases the potential for sampling error in experimental results. In such cases, a subset may be tested that is not representative of the whole. Researchers design experiments carefully to minimize sampling error and bias, and they use probability calculations to check the statistical significance of their results.

Science helps us be objective about our observations because it is concerned only with testable ideas about observable aspects of nature. Opinion and belief have value in human culture, but they are not addressed by science. A scientific theory is a long-standing hypothesis that is useful for making predictions about other phenomena. It is our best way of objectively describing nature. A law of nature is a phenomenon that occurs without fail, but has an incomplete scientific explanation.

Chapter 1: Invitation to Biology Chapter Review

Book Title: Biology Today and Tomorrow with Physiology

Printed By: Kristina Mack ([email protected]) © 2016 Cengage Learning, Cengage Learning

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