Introduction to Biology Chapter 1

Biology is the study of LIFE!

Big Ideas and Recurring Principles Umbrella Concepts Big Ideas and Recurring Principles

Big Ideas in AP Biology Big Idea 1: The process of evolution drives the diversity and unity of life.

Organizing Life’s Diversity Making sense out of the diversity Hierarchical scheme AP Link—

“Nothing in biology makes sense except in the light of evolution.” — Theodosius Dobzhansky

Evolution core theme of biology Charles Darwin

Evolution evolutionary adaptation is a product of natural selection Organisms don’t adapt; Organisms have adaptations.

Unity & Diversity Dual aspects of life on earth Unity Diversity What do organisms have in common? Why do similarities exist? Diversity What differences are there between organisms? ANY Thoughts??

Evolution explains unity & diversity common biochemistry & physiology evolutionary relationships connected through common ancestor Diversity natural selection adaptations allow different individuals to survive in different environments

Big Ideas in AP Biology Big Idea 2: Biological systems utilize free energy and molecular building blocks to grow, to reproduce and to maintain dynamic homeostasis.

Energy Transfer Entropy rules! life is an open system organisms continuously interact with the environment stuff comes in stuff goes out energy is used Entropy rules!

Energy Transfer

Levels of organization

Form follows function structure & function are correlated at all levels of biological organization

Big Ideas in AP Biology Big Idea 3: Living systems store, retrieve, transmit and respond to information essential to life processes.

Continuity & Change Continuity of life is based on heritable information in the form of DNA DNA – the genetic material – carries biological information from 1 generation to the next

Which science is growing the fastest in new knowledge? MOLECULAR BIOLOGY!! Genomics & proteomics projects are driving research

Big Ideas in AP Biology Big Idea 4: Biological systems interact, and these systems and their interactions possess complex properties.

Regulation Organisms need to maintain a “steady state” in the face of changing conditions Homeostasis achieve this through feedback monitor the body like a thermostat turn on when it’s needed, off when its not

Interdependence no organism is an island standing alone

Science, Technology & Society science & technology must function within the framework of society bioethics

Themes Science as a process of inquiry Evolution Energy transfer AP Biology Themes Science as a process of inquiry questioning & investigation Evolution Energy transfer Continuity & Change Relationship of structure to function Regulation Interdependence in nature Science, technology & society

The Scientific Method & Experimental Design

What is Inquiry? Begins with observations you make about the natural world, followed by a question. What is causing that? Use a variety of methods to answer the questions you raise Lab & field investigations, models, simulations, data sets Scientific method of investigation is cyclic, not linear…why?

The Scientific Method: Make Observation Statement of problem, ask a question Hypothesis: propose a tentative answer Design & conduct an experiment (Use quantifiable data  math is extremely important) Use statistical tests to evaluate the significance of your results (Χ2 test, null hypothesis) Acceptance or rejection of hypothesis.

Data Are recorded observations Can be quantitative or qualitative Figure 1.24

The Role of Hypotheses in Inquiry In science, a hypothesis Is a tentative answer to a well-framed question, an explanation on trial Makes predictions that can be tested

We all use hypotheses in solving everyday problems Observations Questions Hypothesis # 1: Dead batteries Hypothesis # 2: Burnt-out bulb Prediction: Replacing batteries will fix problem Replacing bulb Test prediction Test does not falsify hypothesis Test falsifies hypothesis Figure 1.25 We all use hypotheses in solving everyday problems

A Closer Look at Hypotheses in Scientific Inquiry A scientific hypothesis must have two important qualities It must be testable It must have the potential of being rejected "No amount of experimentation can ever prove me right, one single experiment can prove me wrong." --- Albert Einstein.

Designing Controlled Experiments In controlled experiments we start with two (or more) groups that are as similar as possible and we devise a method to manipulate only ONE variable. Independent Variable =the variable that is manipulated Dependent Variable = the response that is measured

Null Hypothesis The premise that any observed differences are simply the result of random differences When quantified observations, or data, are collected, statistical methods are used to calculate the likelihood that the null hypothesis is correct.

Experiments Most mammals, like those who attacked the artificial snake shown in the figure below, cannot see color. With this idea in mind, choose the experiment that would best test whether the color of the artificial snakes were important.

Choose the experiment that would best test whether the color of the artificial snakes were important. Compare attack rates on red-black-white ringed artificial snakes to attack rates on black-brown-white ringed artificial snakes in areas without coral snakes. Measure attack rates on black-brown-white ringed snakes in areas with many coral snakes. Compare attack rates on black-brown-white striped artificial snakes to attack rates on black-brown-white ringed artificial snakes in areas with many coral snakes. Compare attack rates on black-brown-white ringed artificial snakes to attack rates on plain brown artificial snakes in areas with many coral snakes. Compare attack rates on red-black-white ringed artificial snakes to attack rates on black-brown-white artificial snakes in areas with many coral snakes. Answer: e This question is designed to make students think about experimental design. To have meaning, an experiment to test the proposed question should compare colored (red-black-white) to black-brown-white models and the experiment should be conducted in an area with coral snakes. Answer a is wrong because the question is only relevant in areas where there are coral snakes. Answer b is wrong because there needs to be a comparison, not just a measurement. Answer c is wrong because two variables (color and ring/stripe) are being manipulated simultaneously and so the cause of any differences could not be distinguished. Answer d is not the best because there is no difference in color; however, this would be a reasonable experiment to conduct and would test for the effect of rings, though not effect of color. Answer e is the best because it compares color differences in an area with coral snakes.