1. INTRODUCTION TO BIOLOGY Ch 1 Concepts and Connections

2. –Biology is connected to many important issues in our lives Environmental problems and solutions Genetic engineering Medicine

3. What is Biology? Scientific study of life Lays the foundation for asking basic questions about life and the natural world

4. Evolution of Biology As a Science Through the Middle Ages –Major scientific discoveries were made in early Egypt, Babylonia, and Greece –Between 200 and 1200 AD there were almost no important scientific advances –No real distinction made between science and theology –Not much questioning of anything

5. Evolution of Biology As a Science New Era in Biological Sciences –Did not begin until the middle of the nineteenth century –Began when Pasteur finally disproved “spontaneous generation” –Darwin’s work on evolution was the beginning of the same kind of revolution in biology that Newton’s began in physics

6. Spontaneous Generation This was the prevailing scientific view for over 300 years Living things can come from non living things. Organisms are regularly generated from non living materials –Put Garbage in the street Rats generate spontaneously –Hang meat in open stalls Maggots appear –Put broth on the window sill to cool Bacteria grow

7. Disproving Spontaneous Generation Louis Pasteur –Boiled nutrient mixture in flask with long s-shaped necks –Almost all flasks treated this way remained free of bacterial growth as long as the neck was unbroken –When Pasteur tilted the flask so that the broth reached the lowest point in the neck, where any airborne particles would have settled, the broth rapidly became cloudy with life –Concluded that microorganisms were brought into flask on dust particles rather than generated from the nutrient mixture

8. Pasteur’s Experiment

9. THE SCOPE OF BIOLOGY Life’s levels of organization define the scope of biology –Life’s structural hierarchy Defines the scope of biology, the scientific study of life Biosphere Ecosystem Florida coast Community All organisms on the Florida coast Population Group of brown pelicans Organism Brown pelican Organ system Nervous system Organ Brain Tissue Nervous tissue Cell Nerve cell Organelle Nucleus Molecule DNA Atom Nucleus Brain Spinal cord Nerve Figure 1.1

10. LEVELS OF ORGANIZATION The levels in which life is organized are from the largest to the smallest : Biosphere Each level is built of parts from the lower levels. Ecosystem With each step up in the organizational levels new Community properties emerge. Population Organism Organ system Organ Tissue Cell Organelles Molecules Atoms

11. –An ecosystem consists of all the organisms living in a par ticular area As well as the nonliving environmental components –All the living organisms in an ecosystem Make up a community

12. –A population Consists of a localized group of individuals of a species –An individual living entity Is an organism

13. Living organisms and their environments form interconnecting webs –Ecosystems are characterized by the cycling of chemical nutrients from the atmosphere and soil To producers to consumers to decomposers and back to the environment

14. Living things do not exist by themselves Living things interact with the non-living components of the environment. PRODUCERS- plants use carbon dioxide, minerals, water, sunlight energy. COMSUMERS- animals use plants, minerals, water, oxygen. DECOMPOSERS- such as prokaryotes and fungi recycle organic matter back to the environment

15. Two main processes in an ecosystem Recycle of chemicals Energy flow Organisms are open systems that exchange materials and energy with their surroundings.

16. –Energy flows one-way through an ecosystem From the sun to producers to consumers and exits as heat Sun Air CO 2 O2O2 H2OH2O Chemical energy Inflow of light energy Loss of heat energy Producers Cycling of Chemical nutrients Consumers Decomposers Soil Ecosystem Figure 1.2

17. Cells are the structural and functional units of life –A cell Is the basic unit of life

18. All organisms are composed of cells Two type of cells: Prokaryotic cells found in bacteria and archaea Eukaryotic cells found in plants and animals What do they have in common? All cells use DNA as the genetic material

19. –Eukaryotic cells Contain membrane-enclosed organelles, including a DNA-containing nucleus –Prokaryotic cells Lack such organelles Nucleus (contains DNA) Eukar yotic cell Prokar yotic cell DNA (no nucleus) Organelles 25,000  Figure 1.3

20. –All organisms share a common set of features Ordered structures Regulation of internal conditions Figure 1.4BFigure 1.4C

21. How Do We Know If It is Alive? Characteristics of life: 1. Order –All organisms are highly organized –Maintain that organization by expending energy –Each type usually has definite form and shape –All organisms are composed of cells Non-living things do not maintain their organization by expending energy

22. How Do We Know If It is Alive? Characteristics of life: 2. Growth and Development –Organisms develop new parts between or within older parts Non-living things can grow only by addition of material to the outside

23. Characteristics of life: 3. Reproduction- DNA –Each kind of living thing reproduces itself in kind –Information needed to develop and reproduce is segregated within the organism –Information needed to develop and reproduce is passed to offspring Non-living things do not reproduce

24. Characteristics of life: 4. Energy Use Organisms cannot live without energy Metabolism is the sum total of all reactions involved in getting and using energy

25. Characteristics of life: 5. Irritability –Response to environmental stimuli Many forms May not be proportional to stimulus Organism not usually permanently altered by the stimulus Non-living things may react to stimuli –Always a quantitative relationship between the stimulus and the effect

26. Characteristics of life: 6. Regulation of internal conditions This is also known as Homeostasis. The body tries to maintain a state of equilibrium. Examples: thermoregulation ( maintaining temperature within certain limits) Excretion and hydration

27. Characteristics of life: 7. Evolution and Adaptation –Groups of organisms change over time –Changes make organisms more able to live in the particular local environment Non-living things do not change nor adapt to the environment

28. Characteristics of life: 1.ORDER: all living things have complex organization, are composed of the same chemical substances and made up of cells 2. REGULATION: organisms regulate their internal environment, this is called HOMEOSTASIS 3. GROWTH AND DEVELOPMENT: genes control the pattern of growth and development. 4. ENERGY USE: all organism engage in metabolism.Energy is taken in and transformed to a usable form 5. RESPONSE TO THE ENVIRONMENT: Sense and respond to the outside environment 6. REPRODUCTION: Have the capacity to reproduce based on instructions in DNA 7. EVOLUTION: organisms change over time

29. The diversity of life can be arranged into three domains –Organisms are grouped (classified) Into the prokaryotic domains Bacteria and Archaea and the eukaryotic domain Eukarya

30. The three domains of life Domain Archaea (oldest, most primitive) Domain Bacteria Domain Eukarya plants animals fungi

31. SEM 25,000  Figure 1.5B –Domains Bacteria and Archaea SEM 3,250  Figure 1.5A

32. –Domain Eukarya includes Protists (protozoans and algae, falling into multiple kingdoms) The kingdoms Fungi, Plantae, and Animalia 275  Protists (multiple kingdoms) Kingdom Fungi Kingdom Animalia Kingdom Plantae Figure 1.5C

33. Diversity of Life Millions of living species Additional millions of species now extinct Classification scheme attempts to organize this diversity

34. EVOLUTION, UNITY, AND DIVERSITY The unity of life: All forms of life have common features –DNA is the genetic information For constructing the molecules that make up cells and organisms

35. –Each species’ genetic instructions Are coded in the sequences of the four building blocks making up DNA’s two helically coiled chains A C T A T A C C G T A G T A Figure 1.4A

36. Figure 1.10 Classifying life

37. Structure and Function Correlated at all levels of life A bird’s shape and it’s skeleton –Make flight possible Aerodynamic shape of wing Honeycombed construction of bone A cell’s form fits its specialized function –Nerve cells have long extensions that transmit signals At the sub-cellular level –Inner membrane of mitochondrion is folded to provide more surface area

38. Evolution explains the unity and diversity of life –Charles Dar win Synthesized the theory of evolution by natural selection Figure 1.6A

39. Darwin’s Voyage At age 22, Charles Darwin began a five- year, round-the-world voyage aboard the Beagle In his role as ship’s naturalist he collected and examined the species that inhabited the regions the ship visited

40. Voyage of the Beagle

41. Darwin’s Theory Rejects the notion that living creatures are immutable products of a sudden creation. A population can change over time when individuals differ in one or more heritable traits that are responsible for differences in the ability to survive and reproduce

42. On the Origin of Species Darwin’s book Published in 1859 Laid out in great detail his evidence in support of the theory of evolution by natural selection

43. Two Parts of Darwin’s Theory Descent with modification –Change is the rule rather than the exception –Organisms living today have descended by gradual changes from ancient ancestors quite unlike themselves Natural selection determines the course of the change –It is a completely mechanistic process without conscious purpose or design –individuals differ in one or more heritable traits that are responsible for differences in the ability to survive and reproduce

44. THE PROCESS OF SCIENCE –Science Is a way of knowing Scientists are always asking questions about nature and looking for answers about natural phenomena Scientists use two main approaches to learn about nature.

45. Discovery Science –In discovery science Scientists describe some aspect of the world and use inductive reasoning to draw general conclusions

46. Inductive Logic Using observations and facts to arrive at generalizations or hypotheses Observation: Eagles, swallows, and robins have feathers Hypothesis: All birds have feathers

47. Hypothesis-Based Science –In hypothesis-based science Scientists attempt to explain obser vations by testing hypotheses

48. With hypothesis-based science, we pose and test hypotheses –Hypothesis-based science involves Obser vations, questions, hypotheses as tentative answers to questions Deductions leading to predictions, and then tests of predictions to see if a hypothesis is falsifiable

49. A Case Study from Ever yday Life –Deductive reasoning is used in testing hypotheses as follows If a hypothesis is correct, and we test it, then we can expect a par ticular outcome Observations Question 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 Figure 1.8A

50. Deductive Logic Drawing a specific conclusion based on a generalization –Generalization - Birds have feathers –Example - Eagles are birds –Conclusion - Eagles have feathers

51. Scientific Method Observe phenomenon Develop hypotheses Make predictions Devise test of predictions ( experiment) Carry out experiment and analyze results Draw conclusion

52. Figure 1.19 Idealized version of the scientific method

53. Figure 1.21 Controlled experiments to test the hypothesis that selective predation affects the evolution of guppy populations

54. Experimental Design Control group –A standard for comparison –Identical to experimental group except for variable being studied Sampling error –Minimize by using large samples –Experiment must be repeatable

55. Fig. 1.10, p. 12 CONTROL GROUP The variable being tested is absent EXPERIMENTAL GROUP The variable being tested is present Draw samples from some aspect of nature Compile results Compare and analyze the test results Report on experimental design, test results, and conclusions drawn from results

56. Scientific Theory A hypothesis that has been tested for its predictive power many times and has not yet been found incorrect Has wide-ranging explanatory power –Darwin’s Theory of Evolution by Natural Selection

57. Limits of Science Scientific approach cannot provide answers to subjective questions Cannot provide moral, aesthetic, religious or philosophical standards

58. Science and the Supernatural Science has run up against religious belief systems –Copernicus suggested that sun, not the Earth, was center of universe –Darwin suggested that life was shaped by evolution, not a single creation event

59. Asking Questions Scientists still ask questions that challenge widely held beliefs The external world, not internal conviction, is the testing ground for scientific beliefs

60. 1. What are the three domains of life/ 2. What theory explains the “unity and diversity of life”? 3. What is evolution? Who was the first person that proposed this theory? 4. How do scientist go about finding answers to questions? 5. What are three requirements for an experiment to be valid? 6. What is the meaning of the word “theory” in science? 7.What are the limitations of the scientific method?