The Science of Biology Chapter 1

What are the Goals of Science All objects in the universe, and all interactions among these objects, are governed by universal, natural laws. The same, natural laws apply whether the objects or events are large or small. Aristotle and other Greek philosophers were among the first to try to view the universe this way. They wanted to explain the world around them in terms of events and processes they could observe.

What are the Goals of Science 1. To provide natural explanations for events in the natural world. 2. To use those explanations to understand patterns in nature and to make useful predictions about natural events.

What is the Scientific Method? How Scientists Work What is the Scientific Method? Techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge.

How Scientists Work What are the steps of the scientific method? Observation of Phenomena Creating a question Forming a hypothesis Controlled Experiment Analyze Data & Make Conclusion Repeat Peer Review

How Scientists Work What are the steps of the scientific method? Observation of Phenomena What are phenomena? Facts or occurrences that can be observed. 2. Creating a question (5W’s & 1H) Who, What, When, Where, Why & How.

How Scientists Work What are the steps of the scientific method? Forming a hypothesis Definition: a possible answer to why the phenomena occurred. The scientist expects his hypothesis to be correct; it is a prediction. Written as an “If . . . then . . .” statement. “If” part = manipulated/independent variable. “Then” part = responding/dependent variable

How Scientists Work What are the steps of the scientific method? Controlled Experiment: tests the hypothesis Has two parts: Control group – no variables; for comparison Experimental group – has both of the variables

How Scientists Work What are the steps of the scientific method? Controlled Experiment: Manipulated/Independent variable – deliberately changed; it is the difference between the control & experimental groups. Responding/Dependent variable – the change that is caused by the manipulated variable. It can be observed & measured.

How Scientists Work What are the steps of the scientific method? Analyze Data & Make Conclusion What is data? Information collected from the experiment Two types: A. Quantitative (numbers) B. Qualitative (descriptive) Conclusion: Is the hypothesis correct? Why? Repeat Why? Consistent data supports your conclusion.

How Scientists Work What are the steps of the scientific method? Peer Review: Other scientists review your work and give their opinions on the validity of your conclusion. How is this done? A. E-mail B. Presentations at a conference, webinars, etc. C. Publish in a scientific journal like Nature or Science

How Scientists Work What is a theory? It is a hypothesis that has lots of evidence to support. Book Definition: A well-tested explanation that unifies a broad range of observations and hypotheses that enables scientists to make accurate predictions about new situations. Scientists use theories to help make predictions, but theories are not laws. A theory can be changed or discarded with the discovery of new evidence.

Studying Life What is biology? The study of life. Bio = life; logy = study of What are some of the branches of biology? Zoology – study of animals Botany – study of plants Biochemistry – study of life’s chemistry Paleontologists – study ancient life

Studying Life Prior to the Renaissance & Enlightenment: Most Europeans believed in abiogenesis/spontaneous generation (life just magically appears from non-living things). During the Enlightenment, application of the scientific method proved the theory of biogenesis (life only comes from other living things).

Studying Life What are the characteristics of life? (Central Themes) Made up of cells Reproduce Universal genetic code Growth & Development Obtain & use materials & energy Respond to stimuli Homeostasis Evolve

Studying Life What are the characteristics of life? All living things are made up of cells. Multicellular – made of many cells; must have some specialized cells (cells that have special shapes & functions) Unicellular – made of only one cell

Studying Life What are the characteristics of life? A living things reproduce. Two types of reproduction: A. Asexual – offspring is genetically identical to the parent. Pros: easy to do. Cons: no genetic variety B. Sexual – offspring is genetically different than the parents Pros: lots of genetic variety Cons: harder to do

Studying Life What are the characteristics of life? All living things use a universal genetic code. All organisms use DNA to pass on information to the next generation. DNA contains the information to produce proteins. Proteins control the chemistry of life.

Studying Life What are the characteristics of life? All living things grow and develop. Growth – get bigger by producing more cells or making the cells that one has bigger. Development – change in form and function. Some of the cells of the organism can do new things.

Studying Life What are the characteristics of life? All living things obtain and use materials and energy. Materials = the basic biomolecules (carbohydrates, lipids, proteins & nucleic acids) Energy = the ability to do work. Typically stored in chemical bonds.

Studying Life What are the characteristics of life? All living things respond to their environment. Stimuli = environmental signal that cause a response All living things maintain a stable internal environment. This process is known as homeostasis. A stable internal environment makes the chemistry of life easier to occur.

Studying Life What are the characteristics of life? 8. Taken as a group, living things evolve. Evolution occurs by a process called natural selection. Individuals with the best traits reproduce more often and pass on these good traits to the next generation.

Studying Life Tissue: group of similar cells working together Levels of Biological Organization: Tissue: group of similar cells working together Organ: group of similar tissues working together Population: members of same species in a given area Community: many populations in an are Ecosystem: community plus nonliving (abiotic) factors Biosphere: all the places on the planet where life exists