1. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings PowerPoint ® Lecture Presentations for Biology Eighth Edition Neil Campbell and Jane Reece Lectures by Chris Romero, updated by Erin Barley with contributions from Joan Sharp Introduction: Themes in the Study of Life Chapter 1

2. Overview: Inquiring About the World of Life Evolution: process of change transforming life Biology: scientific study of life Scientific Inquiry: biologists ask questions – How a single cell develops into an organism? – How the human mind works? – How living things interact in communities? What defines Life: it’s what we do (next slide)!

3. Order Evolutionary adaptation Response to the environment Reproduction Growth and development Energy processing Regulation Important Properties of Life

4. Concept 1.1: Themes connect biological concepts Themes help to organize biological information Evolution: one heck of a big theme, indeed! All organisms living on Earth are modified descendents of common ancestors

5. Theme 1.1A: New properties emerge at each level in the biological hierarchy The study of life can be divided into different levels of biological organization (see text p. 4-5) 1. The biosphere 3. Communities 4. Populations 5. Organisms 2. Ecosystems 6. Organs and organ systems 8. Cells Cell 9.Organelles Atoms 10. Molecules 7. Tissues 10 µm 1 µm 50 µm

6. Emergent Properties Emergent properties result from the arrangement and interaction of parts as complexity increases within a system Example: An Emergent property in Biology – Photosynthesis (process): involves the specific interaction of components in a Chloroplast Example: A Non-biological Emergent property – A functioning bicycle emerges only when all of the necessary parts connect in the correct way

7. Reductionism Reductionism: the reduction of complex systems to simpler components that are more manageable to study – For example, molecular structure of chlorophyll An understanding of biology connects reductionism (study the one) with emergent properties (integrated function) – For example, new understanding comes from studying the interactions of chlorophyll with other molecules to produce photosynthesis

8. Systems Biology Systems biology constructs models for the dynamic behavior of whole biological systems A system is a combination of components that function together (i.e. the cell or the earth) The systems approach poses questions like: – How does a drug for blood pressure affect other organs? – How does increasing CO 2 alter the biosphere?

9. Theme 1.1B: Organisms interact with their environments, exchanging matter and energy Every organism interacts with its environment and that interaction affects each other. Ecosystem Dynamics & Energy Conversion (see next slide)

10. Ecosystem Dynamics Sunlight (Energy) Ecosystem Heat Cycling of chemical nutrients Producers (plants and other photosynthetic organisms) Chemical energy Consumers (such as animals) 1. Nutrients from the soil are returned to the soil 2. Energy flows from Producers to Comsumers 1. Work (life processes) requires energy 2. Energy is transformed from kinetic (light) to metabolic (chemical) 3. Energy flows through an ecosystem: entering as light and exiting as heat Energy Conversion

11. Theme 1.1C: Structure and function are closely correlated at all levels of biological organization (a) Wings (c) Neurons (b) Bones Infoldings of membrane Mitochondrion (d) Mitochondria 0.5 µm 100 µm

12. Theme 1.1D: Cells are an organism’s basic units of structure and function The cell is the lowest level of organization that can perform all activities required for life All cells: – Are enclosed by a membrane – Use DNA as their genetic information The ability of cells to divide is the basis of all reproduction, growth, and repair of multicellular organisms

13. A eukaryotic cell (plants, animals, fungi) has membrane-enclosed organelles, the largest of which is usually the nucleus A prokaryotic cell (bacteria, archaea) is simpler and usually smaller, and does not contain a nucleus or other membrane-enclosed organelles Other differences too: main one is organellar

14. 1 µm Organelles Nucleus (contains DNA) Cytoplasm Membrane DNA (no nucleus) Membrane Eukaryotic cell Prokaryotic cell

15. Theme1.1E: The continuity of life is based on heritable information in the form of DNA Chromosomes contain most of a cell’s genetic material (genes) as DNA (deoxyribonucleic acid) DNA is the substance of genes Genes are the units of inheritance that transmit information from parents to offspring Thus an organism’s genome is its entire set of genetic instructions (about 30,000 genes), organized on chromosomes (we have 23)

16. DNA Structure and Function Each chromosome has one long DNA molecule (chain) with hundreds or thousands of genes Each link of a chain is one of four kinds of chemical building blocks called nucleotides Each DNA molecule is made up of two long chains arranged in a double helix DNA is transcribed into RNA, RNA then translated into a protein (functional molecule) DNA controls development and maintenance

17. Nucleus DNA Cell Nucleotide (a) DNA double helix(b) Single strand of DNA

18. Systems Biology at the Levels of Cells and Molecules Outer membrane and cell surface Cytoplasm Nucleus Advances are due to: 1. “High-throughput” technology, which yields enormous amounts of data 2. Bioinformatics, which is the use of computational tools to process a large volume of data 3. People: Interdisciplinary research teams

19. Theme 1.1F: Feedback mechanisms regulate biological systems Feedback mechanisms allow biological processes to self-regulate Negative feedback means that as more of a product accumulates, the process that creates it slows and less of the product is produced Positive feedback means that as more of a product accumulates, the process that creates it speeds up and more of the product is produced

20. Excess D blocks a step (a) Negative feedback Negative feedback D D D D C B A Enzyme 1 Enzyme 2 Enzyme 3 –

21. Excess Z stimulates a step (b) Positive feedback Z Positive feedback Enzyme 4 Enzyme 5 Enzyme 6 Z Z Z Y X W +

22. Concept 1.2: The Core Theme: Evolution accounts for the unity and diversity of life Evolution unifies biology at different scales of size throughout the history of life on Earth

23. Organizing the Diversity of Life Approximately 1.8 million species have been identified and named to date, and thousands more are identified each year Estimates of the total number of species that actually exist range from 10 million to over 100 million Most species have gone to extinction

24. Grouping Species: The Basic Idea Taxonomy is the branch of biology that names and classifies species into groups of increasing breadth (see next slide)

25. SpeciesGenusFamilyOrderClassPhylumKingdomDomain Ursus americanus (American black bear) Ursus Ursidae Carnivora Mammalia Chordata Animalia Eukarya Taxonomy Tool: Drunk King Philip Came Over From Greece Stoned

26. (a) DOMAIN BACTERIA (prokaryotic) (b) DOMAIN ARCHAEA (prokaryotic) (c) DOMAIN EUKARYA (eukaryotic) Several Protist Kingdoms Kingdom Fungi Kingdom Plantae Kingdom Animalia The Three Domains of Life

27. Unity in the Diversity of Life A striking unity underlies the diversity of life Cilia of Paramecium Cross section of a cilium, as viewed with an electron microscope Cilia of windpipe cells 15 µm 5 µm 0.1 µm

28. Charles Darwin: Theory of Natural Selection Fossils and other evidence document the evolution of life on Earth over billions of years Charles Darwin published On the Origin of Species by Means of Natural Selection in 1859 Darwin made two main points: – Species have arisen by “descent with modification” from common ancestors using natural selection as the mechanism Darwin’s theory explained the duality of unity and diversity

29. Darwin observed that: – Individuals in a population have heritable, variable traits. More offspring are produced than survive. Competition is inevitable. Species generally suit their environment. Darwin inferred that: – Individuals that are best suited to their environment are more likely to survive and reproduce; producing more individuals in the population with the advantageous traits Natural selection is often evident in adaptations of organisms to their way of life & environment

30. Example of Natural Selection Population with varied inherited traits (in this case, color). Elimination of individuals with certain Traits (light color). Reproduction of survivors (dark colored bugs). Increasing frequency of traits that enhance survival and reproductive success. 43 21

32. The Tree of Life “Unity in diversity” arises from “descent with modification” – For example, the forelimb of the bat, human, and flipper share common skeletal architecture Darwin proposed that natural selection could cause an ancestral species to give rise to two or more descendent species Evolutionary relationships are often illustrated with tree-like diagrams that show ancestors and their descendents (see next slide)

33. Fig. 1-22 COMMON ANCESTOR Warbler finches Insect-eaters Seed-eater Bud-eater Insect-eatersTree finches Green warbler finch Certhidea olivacea Gray warbler finch Certhidea fusca Sharp-beaked ground finch Geospiza difficilis Vegetarian finch Platyspiza crassirostris Mangrove finch Cactospiza heliobates Woodpecker finch Cactospiza pallida Medium tree finch Camarhynchus pauper Large tree finch Camarhynchus psittacula Small tree finch Camarhynchus parvulus Large cactus ground finch Geospiza conirostris Cactus ground finch Geospiza scandens Small ground finch Geospiza fuliginosa Medium ground finch Geospiza fortis Large ground finch Geospiza magnirostris Ground finches Seed-eaters Cactus-flower- eaters Niche’ driven modifications

34. Concept 1.3: Scientists use two main forms of inquiry in their study of nature Inquiry: search for information and explanation There are two main types of scientific inquiry: Discovery science describes nature. Hypothesis-based science explains nature.

35. Discovery Science Describes natural structures and processes Based on observation and analysis of data: recorded observations or items of information Types of Data two categories Qualitative (descriptive) or Quantitative (measured) Inductive reasoning draws conclusions through the logical process of induction: many repeated and specific observations lead to important generalizations. Example: sunrise in the east.

36. Hypothesis-Based Science Observations will lead us to ask questions and propose hypothetical explanations: hypotheses Hypothesis : tentative answer to a well-framed question. Example: Eastern sunrise because… A scientific hypothesis leads to predictions that can be tested by observation or experimentation Deductive reasoning uses general premises to make specific predictions. “If…Then” Logic (see next slide)

37. Example of Scientific Method Observation Your flashlight doesn’t work Question Why doesn’t your flashlight work? Hypothesis #1: Dead batteries Hypothesis #2: Burnt-out bulb Prediction: Replacing batteries will fix problem Prediction: Replacing bulb will fix problem Test prediction Test falsifies hypothesis Test does not falsify hypothesis So test it!

38. A Closer Look at Hypotheses in Scientific Inquiry Hypothesis-based science often makes use of two or more alternative hypotheses (last slide) A hypothesis must be testable and falsifiable Observations and results must be repeatable Experiments must be under controlled conditions meaning that control groups are used to cancel the effects of unwanted variables Failure to falsify a hypothesis does not prove that hypothesis (example: a replaced bulb)

39. Limitations of Science In science, observations and experimental results must be repeatable Science cannot support or falsify supernatural explanations, which are outside the bounds of science

40. Theories in Science In the context of science, a theory is: – Broader in scope than a hypothesis – General, and can lead to new testable hypotheses – Supported by a large body of evidence in comparison to a hypothesis

41. Model Building in Science Models are representations of natural phenomena and can take the form of: – Diagrams – Three-dimensional objects – Computer programs – Mathematical equations

42. From body From lungs Right atrium Left atrium Left ventricle Right ventricle To lungsTo body

43. The Culture of Science Most scientists work in teams, which often include graduate and undergraduate students Good communication is important in order to share results through seminars, publications, and websites

44. Science, Technology, and Society The goal of science is to understand natural phenomena The goal of technology is to apply scientific knowledge for some specific purpose Science and technology are interdependent Biology is marked by “discoveries,” while technology is marked by “inventions” Ethical issues can arise from new technology

45. You should now be able to: 1.Briefly describe the unifying themes that characterize the biological sciences 2.Distinguish among the three domains of life, and the eukaryotic kingdoms 3.Distinguish between the following pairs of terms: discovery science and hypothesis- based science, quantitative and qualitative data, inductive and deductive reasoning, science and technology

47. A Case Study in Scientific Inquiry: Investigating Mimicry in Snake Populations Many poisonous species are brightly colored, which warns potential predators Mimics are harmless species that closely resemble poisonous species Henry Bates hypothesized that this mimicry evolved in harmless species as an evolutionary adaptation that reduces their chances of being eaten

48. This hypothesis was tested with the poisonous eastern coral snake and its mimic the nonpoisonous scarlet kingsnake Both species live in the Carolinas, but the kingsnake is also found in regions without poisonous coral snakes If predators inherit an avoidance of the coral snake’s coloration, then the colorful kingsnake will be attacked less often in the regions where coral snakes are present

49. Fig. 1-25 South Carolina North Carolina Key Scarlet kingsnake (nonpoisonous) Eastern coral snake (poisonous) Range of scarlet kingsnake only Overlapping ranges of scarlet kingsnake and eastern coral snake

50. Field Experiments with Artificial Snakes To test this mimicry hypothesis, researchers made hundreds of artificial snakes: – An experimental group resembling kingsnakes – A control group resembling plain brown snakes Equal numbers of both types were placed at field sites, including areas without poisonous coral snakes

51. Fig. 1-26 (a) Artificial kingsnake (b) Brown artificial snake that has been attacked

52. After four weeks, the scientists retrieved the artificial snakes and counted bite or claw marks The data fit the predictions of the mimicry hypothesis: the ringed snakes were attacked less frequently in the geographic region where coral snakes were found

53. Fig. 1-27 Artificial kingsnakes Brown artificial snakes 83% 84% 17% 16% Coral snakes absent Coral snakes present Percent of total attacks on artificial snakes 100 80 60 40 20 0 RESULTS