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Chapter 1 Exploring Life Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings.

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Presentation on theme: "Chapter 1 Exploring Life Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings."— Presentation transcript:

1 Chapter 1 Exploring Life Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

2 Biology - the scientific study of life The phenomenon we call life – We recognize life by what living things do Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

3 Images : Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings HIGHLY ORDERED

4 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings EVOLUTIONARY ADAPTATION

5 Image from: Venus fly trap © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Image from: RESPOND TO ENVIRONMENT

6 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings REGULATION Living things adjust and control cell processes to maintain conditions suitable for life HOMEOSTASIS

7 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings ENERGY PROCESSING

8 Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings GROWTH & DEVELOPMENT

9 Images: Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Planaria animation: REPRODUCTION

10 Ecosystems Communities Organisms Populations Biosphere A Hierarchy of Biological Organization

11 8 Cells 6 Organs and organ systems 7 Tissues 10 Molecules 9 Organelles 50 µm 10 µm 1 µm Atoms

12 New properties emerge with each step up in hierarchy of biological order Structural arrangement and interaction of parts is important to function!

13 EMERGENT PROPERTIES ~ the sum is greater than the parts Individual amino acids don ’ t catalyze chemical reactions… but proteins do!

14 11 MAJOR THEMES that unify biology Connect concepts and provide a framework for understanding

15 Unifying Themes in Biology connect concepts & provide framework for understanding Evolution ~ biology’s core theme; differential reproductive success Emergent Properties ~ the sum is greater than the parts The Cell ~ basic structure of all organisms Heritable Information ~ DNA Structure & Function ~ form follows function Environmental Interaction ~ organisms are open systems Energy and life ~ work requires energy that flows from sunlight to producers to consumers Regulation ~ feedback mechanisms Unity & Diversity ~ universal genetic code Scientific Inquiry ~ observation; testing; repeatability Science, Technology & Society ~ functions of our world

16 Evolution – Evolution, biology’s core theme, explains both the unity and diversity of life. The Darwinian theory of natural selection accounts for adaptation of populations to their environment through the differential reproductive success of varying individuals. 11 MAJOR THEMES that unify biology

17 EVOLUTION is the CORE THEME SLIDE FROM BIOLOGY ZONE by Kim B. Foglia

18 11 MAJOR THEMES that unify biology Image from Pearson Education © 2005, publishing as Benjamin Cummings Energy and Life – All organisms must perform work, which requires energy. Energy flows from sunlight to producers to consumers. Producers (plants and other photosynthetic organisms) Consumers (including animals) Sunlight Chemical energy Heat Ecosystem

19 11 MAJOR THEMES that unify biology Image from Pearson Education © 2005, publishing as Benjamin Cummings Continuity and Change (Unity & Diversity) – All species tend to maintain themselves from generation to generation using the same genetic code. However, there are genetic mechanisms that lead to change over time, or evolution.

20 Diversity is a hallmark of life BUT... Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

21 ... as diverse as life is, there is also evidence of remarkable unity Cilia of Paramecium. The cilia of Paramecium propel the cell through pond water. Cross section of cilium, as viewed with an electron microscope 15 µm 1.0 µm 5 µm 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.

22 11 MAJOR THEMES that unify biology Images from Pearson Education © 2005, publishing as Benjamin Cummings Structure and Function – Form and function are correlated at all levels of biological organization

23 11 MAJOR THEMES that unify biology Regulation - Everything from cells to organisms to ecosystems is in a state of dynamic balance that must be controlled by positive or negative feedback mechanisms.

24 In feedback regulation – The output, or product, of a process regulates that very process

25 In negative feedback – An accumulation of an end product slows the process that produces that product B A C D Enzyme 1 Enzyme 2 Enzyme 3 D D D D D D D D DD C B A Negative feedback Example: sugar breakdown generates ATP; excess ATP inhibits an enzyme near the beginning of the pathway

26 In positive feedback (less common) – The end product speeds up production WW X Y Z Z Z Z Z Z Z Z Z Z Z ZZ Z ZZ Z Z Z Y X Enzyme 4 Enzyme 5 Enzyme 6 Enzyme 4 Enzyme 5 Enzyme 6 Positive feedback EXAMPLE: Chemicals released by platelets that accumulate at injury site, attract MORE platelets to the site.

27 11 MAJOR THEMES that unify biology Image from BIOLOGY ZONE by Kim B. Foglia Interdependence in Nature – No organism “is an island”. Organisms are open systems that exchange materials and energy with their surroundings.

28 11 MAJOR THEMES that unify biology Image from Pearson Education © 2005, publishing as Benjamin Cummings Science as a Process - Science is a way of knowing. It can involve a discovery process using inductive reasoning, or it can be a process of hypothesis testing.

29 11 MAJOR THEMES that unify biology Image from Pearson Education © 2005, publishing as Benjamin Cummings Science, Technology, and Society – Scientific research often leads to technological advances that can have a positive and/or negative impacts on society as a whole.

30 11 MAJOR THEMES that unify biology Image from Pearson Education © 2005, publishing as Benjamin Cummings Cells are every organism ’ s basic units of structure and function. The TWO main types of cells are: PROKARYOTES (bacteria & archaea) EUKARYOTES (protists, fungi, plants & animals)

31 11 MAJOR THEMES that unify biology HERITABLE INFORMATION- The continuity of life depends on the inheritance of biological information in the form of DNA molecules. This genetic information in encoded in the nucleotide sequences of the DNA

32 11 MAJOR THEMES that unify biology Image from Pearson Education © 2005, publishing as Benjamin Cummings EMERGENT PROPERTIES- The living world has a hierarchical organization, extending from molecules to the biosphere. With each step upward in level, system properties emerge as a result of interactions among components at the lower levels.

33 How can we understand biological systems? DILEMMA: Because of EMERGENT PROPERTIES we can ’ t fully explain a higher level of order by breaking it into parts, but... organisms are too complex to analyze without taking them apart! TWO STRATEGIES : REDUCTIONISM SYSTEMS BIOLOGY

34 REDUCTIONISM Reducing complex systems to simpler components that are more manageable to study EXAMPLE: By studying the molecular structure of DNA, James Watson & Francis Crick were able to infer how this molecule could serve as the chemical basis of inheritance

35 The study of DNA structure has led to further study of heredity, such as the Human Genome Project Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

36 https://www.genome-sci.jp/english/images/zu2.gif SYSTEMS BIOLOGY tries to understand how all parts are functionally integrated

37 Systems biology Seeks to create models – Diagrams – Graphs – 3-D objects – Computer programs – Mathematical equations models of ideas, structures, and processes help us understand scientific phenomena and make predictions To lungs To body Right artium Right ventricle From lungs From body Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

38 Concept 1.5: Biologists use various forms of inquiry to explore life At the heart of science is inquiry – A search for information and explanation, often focusing on specific questions Biology blends two main processes of scientific inquiry – Discovery science – Hypothesis-based science

39 Discovery science – Describes natural structures and processes as accurately as possible through careful observation and analysis of data Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

40 Types of Data DATA are recorded observations Can be: – Quantitative involves analysis of numerical data (measure, count, etc) – Qualitative involves analysis of data such as words (e.g., from interviews), pictures (e.g., video), or objects (e.g., an artifact). Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

41 Induction in Discovery Science In inductive reasoning – Scientists derive generalizations based on a large number of specific observations EX: “ The sun always rises in the East. ” “ All living things are made of cells. ”

42 Hypothesis-Based Science (Deductive reasoning) Inquiry that asks specific questions – Usually involves the proposing and testing of hypothetical explanations, or hypotheses Hypothesis – Is a tentative answer to a well-framed question, an explanation on trial – Makes predictions that can be tested – Usually expressed as an: If…., then …. statement

43 Deduction: The “ If…then ” Logic of Hypothesis-Based Science In deductive reasoning – The logic flows from the general to the specific If a hypothesis is correct – Then we can expect a particular outcome

44 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 Prediction: Replacing bulb will fix problem Test prediction Test does not falsify hypothesis Test prediction Test falsifies hypothesis Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

45 A Closer Look at Hypotheses in Scientific Inquiry A scientific hypothesis must have two important qualities – It must be testable – It must be falsifiable An hypothesis can only be proven to be FALSE, never proven to be TRUE!

46 The Myth of the Scientific Method The scientific method – is an idealized process of inquiry There is not “ ONE ” method May design experiment, then backtrack when realize need more observations May redirect research if realize been “ barking up wrong tree ” Hind sight is 20/20

47 EXPERIMENTAL DESIGN A CONTROLLED experiment must see the effect of ONE VARIABLE at a time Hard to do in field/lab Don ’ t eliminate unwanted variables…. cancel their effects by using a CONTROL GROUP Must be repeated (at least 3 X) Can ’ t ignore or rule out data which do not support the hypothesis

48 VARIABLES A variable is any factor, trait, or condition that can exist in differing amounts or types. – independent variable is the one that is changed by the scientist. – dependent variable is observed to see how it responds to the change made to the independent variable. The new value of the dependent variable is caused by and depends on the value of the independent variable. – controlled variables. are quantities that a scientist wants to remain constant, and must be observed as carefully as the dependent variables.

49 HYPOTHESISIndependent variable (What I change) Dependent variable (What I observe) Controlled variables (What I keep the same) If fertilizer is added, then a plant will grow bigger. Measure amount of fertilizer (grams) Growth of the plant measured by its height Growth of the plant measured by the number of leaves There are other ways to measure growth Same size pot Same type of plant Same type and amount of soil Same amount of water and light Make measurements of growth for each plant at the same time The many variables above can each change how fast a plant grows, so to insure a fair test of the fertilizer, each of them must be kept the same for every pot.

50 “ IT ’ S JUST A THEORY ” In every day conversation, a theory often implies an untested guess. In science, the word “ theory ” means something different than in common usage. Broader than a hypothesis General enough to spin off more hypotheses Supported by a massive body of evidence

51 “ IT ’ S JUST A THEORY ” A theory is a well supported, testable explanation of natural phenomena. EX: Cell Theory, Gravitational theory, or Atomic theory

52 TECHNOLOGY applies scientific knowledge for a specific purpose Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings


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