CHAPTER 1 Introduction: The Scientific Study of Life

1. CHAPTER 1Introduction: The Scientific Study of Life Modules 1.1 – 1.3

2. Life in the Trees • The lives of gray-headed flying foxes are closely entwined with the lives of the eucalyptus trees that form their habitat • Eucalyptus trees provide food and roosting sites for the flying foxes • Flying foxes aid in eucalyptus pollinationand help disperse the resulting seeds

3. Flying foxes are becoming an endangered species, partly because of habitat destruction

4. THE SCOPE OF BIOLOGY • Biology is the scientific study of life • Interactions between different kinds of organisms affect the lives of all • Recall the example of flying foxes and eucalyptus trees

5. 1.1 Life’s levels of organization define the scope of biology • A structural hierarchy of life, from molecules to ecosystems, defines the scope of biology • An ecosystem consists of: • all organisms living in a particular area • all nonliving physical components of the environment that affect the organisms (soil, water)

6. ECOSYSTEM LEVELEucalyptus forest • Ecosystems include: • all the organisms in an area, which make up a community • interbreeding organisms of the same species, a population • At the top of life’s hierarchy is the ecosystem COMMUNITY LEVELAll organisms ineucalyptus forest POPULATION LEVELGroup of flying foxes ORGANISM LEVELFlying fox Brain Spinal cord ORGAN SYSTEM LEVELNervous system ORGAN LEVELBrain Nerve TISSUE LEVELNervous tissue CELLULAR LEVELNerve cell MOLECULAR LEVELMolecule of DNA Figure 1.1

7. organ systems • organs • tissues • cells • molecules ECOSYSTEM LEVELEucalyptus forest • Organisms are made up of: COMMUNITY LEVELAll organisms ineucalyptus forest POPULATION LEVELGroup of flying foxes ORGANISM LEVELFlying fox Brain Spinal cord ORGAN SYSTEM LEVELNervous system ORGAN LEVELBrain Nerve TISSUE LEVELNervous tissue CELLULAR LEVELNerve cell MOLECULAR LEVELMolecule of DNA Figure 1.1

8. THE PROCESS OF SCIENCE 1.2 Scientists use two main approaches to learn about nature • In discovery science, scientists describe some aspect of the world and use inductive reasoning to draw general conclusions • Example: scientists have described how newborn flying foxes cling to their mother’s chest for the first weeks of life * Based on observations and measurements Figure 1.2

9. They propose a hypothesis • They make deductions leading to predictions • They then test the hypothesis by seeing if the predictions come true • In hypothesis-driven science, scientists use the “scientific method”

10. http://www.youtube.com/watch?v=jPaGOHwv7mQ

11. 1.3 With the scientific method, we pose and test hypotheses Observation • The main steps of the scientific method Question Hypothesis Prediction Test does notsupport hypothesis; revise hypothesis or pose new one Test supports hypothesis; make additional predictions and test them Test: Experiment oradditionalobservation Figure 1.3A

12. If a hypothesis is correct, and we test it, then we can expect a particular outcome • Case study: flashlight failure • What do we do and what are possible outcomes? Discuss with partner • Deductive reasoning is used in testing hypotheses Figure 1.3B

13. Control groups must be tested along with experimental groups for the meaning of the results to be clear • Controls provide comparison and must be repeatable • Science needs to be testable • Experiments designed to test hypotheses must be controlled experiments

14. Case study: spider mimicry Figure 1.3C So what do you notice between the spider and the fly? Explain the graph to the right. Pounce rate (% of trials in which spider jumped on fly) Control group(untreated flies) Experimental group(wing markings masked) Figure 1.3D

15. Another test of the spider mimic hypothesis: wing transplants Number of stalk andattack responsesby spiders Wingmarkings Wingwaving Normalspidermimic Mimic withmimic wing transplant Mimic withhousefly wing transplant Housefly withmimic wing transplant Normalhousefly Figure 1.3E Controls Experimentals

16. EVOLUTION, UNITY, AND DIVERSITY 1.4 The diversity of life can be arranged into three domains • Grouping organisms by fundamental features helps make the vast diversity of life manageable for study • Scientists classify organisms into a hierarchy of broader and broader groups

17. Domain Bacteria • Most classification schemes group organisms into three domains: • Domain Archaea Figure 1.4A, B

18. Domain Eukarya Figure 1.4C-F

19. Know basic characteristics of each Domain as well as the eukaryotic Kingdoms.

20. 1.5 Unity in diversity: All forms of life have common features • All organisms share a set of common features, signs of unity in life’s vast diversity • All are made of cells • All have DNA as their genetic blueprint • These orchids show the variety possible within one species Figure 1.5A

21. Each species has its own nucleotide sequence • DNA is made of chemical units called nucleotides Figure 1.5B

22. Order and regulation • Growth and development • Use of energy from the environment • Response to environmental stimuli • Ability to reproduce • Evolutionary change • The genetic information in DNA underlies all of the features that distinguish life from nonlife

23. 1.6 Evolution explains the unity and diversity of life • Charles Darwin is a central figure in biology • He synthesized the theory of evolution by natural selection • A theory in science is a comprehensive idea with broad explanatory power • Evolution is the core theme of biology Figure 1.6A

24. The theory of natural selection explains the main mechanism whereby all species of organisms change, or evolve (1) Population with varied inherited traits (2) Elimination of individuals with certain traits (3) Reproduction of survivors Figure 1.6B

25. With your group • Pick an organism and then decide which adaptations make it uniquely suitable for where it is found. Why these adaptations for this environment? Is there a better way, or what might happen in the future?

26. Evolution happens when populations of organisms with inherited variations are exposed to environmental factors that favor the success of some individuals over others • Natural selection is the editing mechanism • Evolution is based on adaptations Figure 1.6C

27. Which of the following statements is not related to Darwin's theories of evolution? (Module 1.6) •   Natural selection is not a creative process. •   Organisms seem to produce more offspring than the environment can support. •   DNA carries genetic information from generation to generation. •   Darwin called the evolutionary process "descent with modification."

28. DNA carries genetic information from generation to generation.

29. 1.7 Living organisms and their environments form interconnecting webs • The theory of natural selection applies to all levels in life’s hierarchy • In an ecosystem, these interactions make up a complex web of relationships • The functional aspects of an ecosystem come from the structure of the ecosystem’s web • This is an interaction of living and non-living components.

30. A web of interactions in a rain forest ecosystem Figure 1.7A

31. This African sunbird is consuming nectar, a plant product • Plants, or plant products, are the ultimate sources of food in an ecosystem Figure 1.7B

32. Energy flows in and out constantly Sun • Chemical nutrients cycle within an ecosystem’s web Inflowoflightenergy Lossofheatenergy Air Chemicalenergy Cyclingofchemicalnutrients Organisms Soil Figure 1.7C ECOSYSTEM

33. BIOLOGY AND EVERYDAY LIFE 1.8 Connection: Biology is connected to our lives in many ways • Biology is connected to a great number of important issues • Environmental problems and solutions • Genetic engineering • Medicine Figure 1.8A

34. Evaluating everyday reports in the press about a large range of subjects requires critical thinking and some familiarity with many areas of biology • In order to understand how rain forest destruction impacts global climate, it is important to understand biology from the molecular to the ecosystem level • Many technological advances stem from the scientific study of life Figure 1.8B