KEY CONCEPT Biology is the study of all forms of life.

1. 1.1 The Study of Life KEY CONCEPT Biology is the study of all forms of life.

2. biosphere = everywhere life exists Earth is home to an incredible diversity of life. • The biosphere includes all living things and all the places they are found.

3. Earth is home to an incredible diversity of life. • Every part of the biosphere is connected with every other part. • The biosphere includes many environments. • land environments • saltwater and freshwater environments

4. Biodiversity is the variety of life. • Biodiversity generally increases from the poles to the equator. • Biodiversity is greater in areas with consistently warm temperatures. Biodiversity is greater closer to the equator.

5. A species is one particular type of living thing. • Members of a species can interbreed to reproduce. • There are about 2 million different living species have been identified. Honeypot ants live in deserts. Some of the ants act as storage tanks for other ants in the colony.

6. All organisms share certain characteristics. • An organism is any individual living thing. • All are made of one or more cells. • All need energy for metabolism. • All respond to their environment. • All have DNA that they pass on to offspring. Reproductive strategies differ among species. The male gold-specs jawfish protects unhatched eggs by holding it in his mouth.

7. 1.2 Unifying Themes of Biology KEY CONCEPTUnifying themes connect concepts from many fields of biology.

8. All levels of life have systems of related parts. • A system is an organized group of interacting parts. • A cell is a system of chemicals and processes. • A body system includes organs that interact. • An ecosystem includes living and nonliving things that interact.

9. Structure and function are related in biology. • Structure determines function. • Proteins with different structures perform different functions. • Heart muscle cells have a different structure and function than stomach muscle cells. • Different species have different anatomical structures with different functions.

10. Organisms must maintain homeostasis to survive in diverse environments. • Homeostasis is the maintenance of constant internal conditions. • Homeostasis is usually maintained through negative feedback. • Negative feedback systems return a condition to its normal (set) point.

11. Behaviors and adaptations can help maintain homeostasis. The polar bear can maintain homeostasis in very cold climates. Its hollow hair is one adaptation that helps the bear retain its body heat.

12. Evolution explains the unity and diversity of life. • Evolution is the change in living things over time. • The genetic makeup of a population of a species changes. • Evolution can occur through natural selection of adaptations. • Adaptations are beneficial inherited traits that are passed to future generations. Through evolution, some orchids have flowers that look like insects and some insects look like parts of plants.

13. 1.3 Scientific Thinking and Processes KEY CONCEPTScience is a way of thinking, questioning, and gathering evidence.

14. Like all science, biology is a process of inquiry. • Scientists make careful and systematic observations. • Scientists record observations as data. • Quantitative data: observations recorded as measurements—always involve a number • Qualitative data: descriptive data (color, sound, shape, texture etc.) • Scientists form a hypothesis as a possible answer to a question.

15. Scientists test their hypotheses and analyze their data. • Graphs are frequently used to display data (3 types) • Line graphs • X-axis: independent variable • Y-axis: dependent variable • Used to display numerical data that is obtained by counting • Bar graphs • X-axis: independent variable • Y-axis: dependent variable • Most useful for showing trends or continuous change • Pie graphs • Uses circle divided into sections to display data • Each section represents a part of the whole • All sections placed together equal 100% of the whole

16. Biologists use experiments to test hypotheses. • Observational studies allow scientists to describe a phenomenon.

17. Experimental studies allow scientists to determine what causes a phenomenon. • Independent variables are manipulated. • Dependent variables are observed and measured. • Constants are conditions that are kept the same.

18. A theory explains a wide range of observations. • Theories explain a wide range of observations and experimental results. • A theory is supported by a wide range of scientific evidence. • Theories can change based on new evidence. For many years, scientific evidence indicated that stomach ulcers were caused by stress. Then new evidence showed that the ulcers are actually caused by bacteria.

19. 1.4 Biologists’ Tools & Technology KEY CONCEPTTechnology continually changes the way biologists work.

20. stoma Imaging technologies provide new views of life. • A microscope provides an enlarged image of an object. • light microscopes (LM)

21. stoma Imaging technologies provide new views of life. • A microscope provides an enlarged image of an object. • light microscopes (LM) • scanning electron microscopes (SEM)

22. stoma Imaging technologies provide new views of life. • A microscope provides an enlarged image of an object. • light microscopes (LM) • scanning electron microscopes (SEM) • transmission electron microscopes (TEM)

23. Imaging technology is used in medicine. • X-ray images • magnetic resonance imaging (MRI) An x-ray of the human knee shows dense tissues, such as bone, in detail. An MRI shows both soft and dense tissue in detail.

24. Complex systems are modeled on computers. Normal heartbeat • Computer models are used to study systems that cannot be studied directly. • Computer models are used when experiments are not safe, ethical, or practical. Heart attack

25. The tools of molecular genetics give rise to new biological studies. • A gene is a segment of DNA that stores genetic information.

26. Through our understanding of DNA, we can study genetics on a molecular level. • molecular genetics

27. 1.5 Biology and Your Future KEY CONCEPTUnderstanding biology can help you make informed decisions.

28. brain lungs heart liver kidneys • Knowledge of biology helps you understand your health. • food allergies • potential effects of obesity • cancer • effects of alcohol, tobacco, and other drugs Nonsmoker (Normal enzyme levels) Smoker (Lower enzyme levels)

29. Knowledge of biology can help you understand environmental issues. • interactions in ecosystems • pollution • biodiversity Deformities in frogs can be an indication of chemical polution in an ecosystem.

30. Biotechnology offers great promise but also raises many issues. • Biotechnology is the use and application of living things and biological processes. Biotechnology is being used in the search of alternative energy source, as shown in the bioreactor that used algae to produce hydrogen gas.

31. Biotechnology is the use and application of living things and biological processes. • DNA testing in medicine and forensics

32. safety of genetically modified crops • Questions are raised about the use of biotechnology. • spread of undesirable genes • decrease in biodiversity • ethical considerations

33. Biology presents many unanswered questions. • Over the past 50 years, biological knowledge has greatly increased.

34. How are memories stored in the brain? • There are still many questions to answer in biology.

35. capsid nucleic acid lipid envelope surface proteins • How are memories stored in the brain? • There are still many questions to answer in biology. • How do viruses mutate? • Does life exist on planets other than Earth?