Scientific Study of Lifeeeeeeeeeeeeeeeeeeeeee.pptx

biology study oflife

1. Biology is the study of life. The word "biology" is derived from the Greek words "bios" (meaning life) and "logos" (meaning "study"). In general, biologists study the structure, function, growth, origin, evolution and distribution of living organisms.

2. Biology is important because it helps us understand how living things work and how they function and interact on multiple levels( Encyclopedia Britannica ). Advances in biology have helped scientists do things such as develop better medicines and treatments for diseases, understand how a changing environment might affect plants and animals, produce enough food for a growing human population and predict how eating new food or sticking to an exercise regimen might affect our bodies.

3. Scientific Study of Life Learning Targets: Explain what is life Describe the characteristics of life Identify the three main branches of the tree of life and examples Analyze scenarios or problems using the process of scientific method Identify the different concepts of scientific study of life

4. A combination of characteristics distinguishes life: Organization Energy use Internal constancy Reproduction and development Evolution

5. A. Life is Organized Atoms form molecules . These molecules form the organelles inside many cells . An organism consists of one or more cells. In most multicellular organisms, cells form tissues and then organs and organ systems . Whether unicellular or multicellular, multiple individuals of the same species make up populations; multiple populations form communities . Ecosystems include living communities plus their nonliving environment. The biosphere is composed of all the world’s ecosystems.

6. Emergent properties arise from interactions among the parts of an organism.

7. B. Life Requires Energy Life requires energy to maintain its organization and functions. Producers make their food, using energy and nutrients extracted from the nonliving environment. Consumers eat other organisms, living or dead. Decomposers recycle nutrients to the nonliving environment.

8. C. Life Maintains Internal Constancy Organisms must maintain homeostasis , an internal state of constancy in changing environmental conditions.

9. D. Life Reproduces Itself, Grows, and Develop Organisms reproduce asexually, sexually, or both. Asexual reproduction yields virtually identical copies of one parent, whereas sexual reproduction generates tremendous genetic diversity by combining and scrambling DNA from two parents.

10. E. Life Evolves In natural selection , environmental conditions select for organisms with inherited traits that increase the chance of survival and reproduction. Evolution through natural selection explains how common ancestry unites all species, producing diverse organisms with many similarities.

11. The Tree of Life Includes Three Main Branches Taxonomy is the science of classification. Biologists classify types of organisms, or species , according to probable evolutionary relationships. A genus , for example, consists of closely related species. The two broadest taxonomic levels are domain and kingdom.

12. The three domains of life are Archaea, Bacteria, and Eukarya. Within each domain, mode of nutrition and other features distinguish the kingdoms .

13. Scientists Study the Natural World A. The Scientific Method Has Multiple Interrelated Parts Scientific inquiry, which uses the scientific method , is a way of using evidence to evaluate ideas about the natural world. A scientist makes observations, raises questions, and uses reason to construct a testable explanation, or hypothesis . Specific predictions follow from a scientific hypothesis.

14. After collecting data and making conclusions, based on the evidence, the investigator may seek to publish scientific results. Peer review ensures that published studies meet high standards for quality.

15. B. An Experimental Design is a Careful Plan An experiment is a test of a hypothesis carried out in controlled conditions. Sample size is the number of individuals assigned to each treatment. Variables are changeable elements in an experiment. The independent variable is the factor that the investigator manipulates. The dependent variable is what the investigator measures to determine the outcome of the experiment. Standardized variables are held constant for all subjects, including the control group (often a set of subjects receiving no treatment or a placebo ).

16. Example: Experimental Design Components Example #1 Example #2 Sample Size 100 infants Variables Independent variable Dose of vaccines Dependent Variable Number of children with illness of rotavirus Standardized Variable Age and health of children in study Control Lacking active ingredient in vaccine

17. C. Theories Are Comprehensive Explanations A theory is more widely accepted and broader in scope than a hypothesis. The acceptance of scientific ideas may change as new evidence accumulates.

18. D. Scientific Inquiry Has Limitations The scientific method does not always yield a complete explanation, or it may produce ambiguous results. Science cannot answer all questions—only those for which it is possible to develop testable hypotheses. E. Biology Continues to Advance Technology is the practical application of scientific knowledge. Advances in science lead to new technologies. and vice versa.