Chapter 1

1. Chapter 1

2. Biology’s Most Exciting Era • Biology: scientific study of life

3. Figure 1.1 • The phenomenon we call life • Defies a simple, one-sentence definition

4. (b) Evolutionary adaptation (a) Order (c) Response to the environment (e) Energy processing (d) Regulation (f) Growth and development (g) Reproduction Figure 1.2 • Some properties of life

5. 1 The biosphere Figure 1.3 A Hierarchy of Biological Organization • From the biosphere to organisms

6. 9Organelles 1 µm Cell 8Cells Atoms 10Molecules 10 µm 7Tissues 50 µm 6Organs and organ systems Figure 1.3 • From cells to molecules

7. Ecosystem Dynamics • 2 major processes • Cycling of nutrients • Flow of energy from sunlight  producers  consumers

8. Sunlight Ecosystem Producers (plants and other photosynthetic organisms) Heat Chemical energy Consumers (including animals) Heat Figure 1.4 • Energy flows through an ecosystem • Entering as sunlight and exiting as heat

9. 25 µm Figure 1.5 Cells • Lowest level of organization that can perform all activities required for life

10. Sperm cell Nuclei containing DNA Embyro’s cells with copies of inherited DNA Fertilized egg with DNA from both parents Egg cell Offspring with traits inherited from both parents Figure 1.6 Cell’s Heritable Information • Chromosomes made partly of DNA, the substance of genes • transmit information from parents to offspring

11. Nucleus DNA Cell A C Nucleotide T A T A C C G T A G T A (a) DNA double helix. This model shows each atom in a segment of DNA.Made up of two long chains of building blocks called nucleotides, a DNA molecule takes the three-dimensional form of a double helix. (b) Single strand of DNA. These geometric shapes and letters are simple symbols for the nucleotides in a small section of one chain of a DNA molecule. Genetic information is encoded in specific sequences of the four types of nucleotides (their names are abbreviated here as A, T, C, and G). Figure 1.7 The molecular structure of DNA

12. Two Main Forms of Cells • Eukaryotic • Prokaryotic

13. Eukaryotic cells • Subdivided by internal membranes into various membrane-enclosed organelles

14. EUKARYOTIC CELL PROKARYOTIC CELL DNA (no nucleus) Membrane Membrane Cytoplasm Organelles 1 µm Figure 1.8 Nucleus (contains DNA) • Prokaryotic cells • Lack membrane-enclosed organelles

15. The study of DNA structure, an example of reductionism • Has led to the Human Genome Project Figure 1.9

16. Species Genus Family Order Class Phylum Kingdom Domain Ursusameri- canus (American black bear) Ursus Ursidae Carnivora Mammalia Chordata Animalia Eukarya Figure 1.14 Taxonomy • Classifying life

17. Bacteria are the most diverse and widespread prokaryotes and are now divided among multiple kingdoms. Each of the rod-shapedstructures in this photo is a bacterial cell. Kingdom Plantae consists of multicellula eukaryotes that carry out photosynthesis, the conversion of light energy to food. Protists (multiple kingdoms) are unicellular eukaryotes and their relatively simple multicellular relatives.Pictured here is an assortment of protists inhabiting pond water. Scientists are currently debating how to split the protistsinto several kingdoms that better represent evolution and diversity. 4 µm 100 µm DOMAIN ARCHAEA Kindom Animalia consists of multicellular eukaryotes thatingest other organisms. Kindom Fungi is defined in part by thenutritional mode of its members, suchas this mushroom, which absorb nutrientsafter decomposing organic material. Many of the prokaryotes known as archaea live in Earth‘s extreme environments, such as salty lakes and boiling hot springs. Domain Archaea includes multiple kingdoms. The photoshows a colony composed of many cells. 0.5 µm Figure 1.15 • Life’s three domains

18. Carolus Linnaeus’s Systema Naturae

19. 15 µm 1.0 µm Cilia of Paramecium.The cilia of Parameciumpropel the cell throughpond water. 5 µm Cross section of cilium, as viewed with an electron microscope Cilia of windpipe cells. The cells that line the human windpipe are equipped with cilia that help keep the lungs clean by moving a film of debris-trapping mucus upward. Figure 1.16 Unity in the Diversity of Life • As diverse as life is there is also evidence of remarkable unity

20. Figure 1.17 • Evolution accounts for life’s unity and diversity • The history of life • Is a saga of a changing Earth billions of years old

21. Figure 1.18 • The evolutionary view of life • Came into sharp focus in 1859 when Charles Darwin published On the Origin of Species by Natural Selection

23. Figure 1.19 • The Origin of Species articulated two main points • Descent with modification (evolution) • Natural selection

24. Population of organisms Overproduction and struggle for existence Hereditary variations Differences in reproductive success Evolution of adaptations in the population Figure 1.20 Natural Selection • Darwin’s mechanism for evolution

25. 1Populations with varied inherited traits 2Elimination of individuals with certain traits. 3Reproduction of survivors. 4Increasing frequency of traits that enhance survival and reproductive success. Figure 1.21

26. Figure 1.22 • The products of natural selection • Are often exquisite adaptations of organisms to the special circumstances of their way of life and their environment

27. Large ground finch Large tree finch Smallground finch Large cactus ground finch Camarhynchuspsitacula Greenwarbler finch Geospiza magnirostris Graywarbler finch Geospizafuliginosa Mediumtree finch Sharp-beaked ground finch Woodpecker finch Mediumground finch Geospiza conirostris Certhideaolivacea Certhideafusca Geospiza difficilis Camarhynchuspauper Cactusground finch Cactospizapallida Mangrovefinch Geospiza fortis Small tree finch Geospizascandens Camarhynchusparvulus Cactospiza heliobates Vegetarianfinch Cactus flowereater Seed eater Seed eater Platyspizacrassirostris Insect eaters Bud eater Ground finches Tree finches Warbler finches Common ancestor fromSouth American mainland Figure 1.23 Natural selection • Ancestral species “split” into two or more descendant species, resulting in a “tree of life”

29. Each species is on twig of a branching tree of life • Extending back in time through ancestral species more and more remote • All of life • Is connected through its long evolutionary history

30. The Myth of the Scientific Method • The scientific method • Is an idealized process of inquiry • Very few scientific inquiries • Adhere to the “textbook” scientific method

31. The Nature of Science Science: observation of the world and the constant testing of theories against nature, with the requirement that everything that is to be called science must be testable The character of science matches the American character Practical, pragmatic, classless, based on evidence Healthy skepticism

32. Rational approach to questions Dull slog through failures to reach a conclusion Answers lead to more questions What is a fact, law, hypothesis, theory? Can only address question that deal with the natural world

33. What science is not Pseudoscience e.g. astrology

34. Limitations of Science • Science cannot address supernatural phenomena • hypotheses must be testable and falsifiable and experimental results must be repeatable

35. Theories in Science • Broad in scope • Generate new hypotheses • Supported by a large body of evidence • Explain • Incorporates confirmed observations, laws, and successfully verified hypotheses

36. Law – description of how a natural phenomenon will occur • Fact – natural phenomenon repeatedly confirmed by observation, e.g. Venus takes 225 days to go around the sun

37. Figure 1.31 The Culture of Science • Social activity • Cooperation and competition

38. Table 1.1 Underlying themes