1. 1 A View of Life Lecture 1

2. 2 Objectives  Define: metabolism, homeostasis, heredity, species, natural selection, evolution, ecology  Outline and describe the properties of life.  Describe evolution and its importance.  Define and list, in order, the levels of organization from the simplest to the most complex.

3. 3 Compare and contrast the flow of energy and materials through an ecosystem. List some ways in which human activities are modifying ecosystems Explain how and why taxonomists classify organisms. List the stages of the scientific process and explain how these steps are used. Note the use of controlled studies. Objectives

4.  Living things: ◦ Comprised of the same chemical elements e.g. Carbon, Hydrogen, and Oxygen ◦ Obey the same physical and chemical laws ◦ Living organisms consist of cells (Unicellular or Multi- cellular).  The cell is the basic structural and functional unit of all living things e.g. plants, animals, and fungus  Cells are produced from preexisting cells  Cells are the smallest units that perform all vital physiological functions 4

5. 5 Living organisms can be Microscopic: Bacteria Paramecium Living organisms can be Macroscopic (Multi-cellular): Snow goose Humans Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. (Bacteria): © Dr. Dennis Kunkel/Phototake; (Paramecium): © M. Abbey/Visuals Unlimited; (Morel): © Royalty-Free Corbis; (Sunflower): © Photodisc Green/Getty Images; (Snow goose): © Charles Bush Photography BacteriaParameciumMorelSunflowerSnow goose

6.  Each level of organization has Emergent Properties  Levels range from extreme micro (e.g. Atoms, Molecules and Cells) to global (e.g. Community, Ecosystem and Biosphere)  Each level of organization is more complex than the level preceding it ◦ Emergent properties:  Interactions between the parts making up the whole  All emergent properties follow the laws of physics and chemistry 6

7. 7 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Organ Composed of tissues functioning together for a specific task Tissue A group of cells with a common structure and function Cell The structural and functional unit of all living things Molecule Union of two or more atoms of the same or different elements Atom Smallest unit of an element composed of electrons, protons, and neutrons Biosphere Regions of the Earth’s crust, waters, and atmosphere inhabited by living things Ecosystem A community plus the physical environment Community Interacting populations in a particular area Population Organisms of the same species in a particular area Organism An individual; complex individuals contain organ systems Organ System Composed of several organs working together

8.  Energy – required to maintaining organization and conducting life-sustaining processes ◦ The sun:  Ultimate source of energy for nearly all life on Earth  Certain organisms, such as plants, capture solar energy to carry on photosynthesis  Photosynthesis transforms solar energy into chemical energy (Organic Molecules)  Chemical energy is used by other organisms e.g. animals ◦ Metabolism is all the chemical reactions that occur in a cell or in an organism.  Homeostasis - Maintenance of internal conditions within certain boundaries 8

9.  Living things interact with the environment and respond to changes in the environment  Response ensures survival of the organism and it often results movement ◦ Vulture can detect and find carcass a mile away and soar toward dinner ◦ Monarch butterfly senses approach of fall and migrates south ◦ Microroganisms can sense light or chemicals ◦ Even leaves of plants follow sun  Activities as a result of Responses are termed behavior 9

10.  Organisms live and die  All living organisms must reproduce to ensure continued existence and maintain population  In most multicellular organisms reproduction: ◦ Begins with union of sperm and egg (fertilization) ◦ Followed by cell division and differentiation ◦ Developmental instructions encoded in genes  Composed of DNA  Long spiral molecule in chromosomes 10

11.  Adaptation ◦ Any modification that makes an organism more suited to its way of life ◦ Organisms become modified over long period time  Respond to environmental changes by developing new adaptations ◦ However, organisms very similar at basic level  Suggests living things descended from same ancestor  Descent with modification - Evolution  Caused by natural selection 11

12.  Despite diversity, organisms share the same basic characteristics ◦ Composed of cells organized in a similar manner ◦ Their genes are composed of DNA ◦ Carry out the same metabolic reactions to acquire energy  This suggests that they are descended from a common ancestor 12

13.  Taxonomy: ◦ Discipline of identifying and classifying organisms according to certain rules ◦ Hierarchical levels (taxa) based on hypothesized evolutionary relationships ◦ Levels are, from least inclusive to most inclusive:  Species, genus, family, order, class, phylum, kingdom, and domain  A level (e.g. phylum) includes more species than the level below it (e.g. class), and fewer species than the one above it (e.g. kingdom) 13

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15.  Bacteria ◦ Microscopic unicellular prokaryotes  Archaea ◦ Bacteria-like unicellular prokaryotes ◦ Extreme aquatic environments  Eukarya ◦ Eukaryotes – Familiar organisms 15

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17. 17 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. BACTERIA ARCHAEA EUKARYA Protists common ancestor (first cells) cell with nucleus Past Time Present Photosynthetic protist Heterotrophic Protist Plants Fungi Animals common ancestor

18. 18 Methanosarcina mazei, an archaeon 1.6 m Prokaryotic cells of various shapes Adaptations to extreme environments Absorb or chemosynthesize food Unique chemical characteristics Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Ralph Robinson/Visuals Unlimited

19. 19 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Prokaryotic cells of various shapes Adaptations to all environments Absorb, photosynthesize, or chemosynthesize food Unique chemical characteristics Escherichia coli, a bacterium 1.5m © A.B. Dowsett/SPL/Photo Researchers, Inc.

20.  Archaea – Kingdoms still being worked out  Bacteria - Kingdoms still being worked out  Eukarya ◦ Kingdom Protista ◦ Kingdom Fungi ◦ Kingdom Plantae ◦ Kingdom Animalia 20

21. 21 KINGDOM: Fungi Coprinus, a shaggy mane mushroom Protists Paramecium, a unicellular protozoan Molds, mushrooms, yeasts, and ringworms Mostly multicellular filaments with specialized, complex cells Absorb food1 Algae, protozoans, slime molds, and water molds Complex single cell (sometimes filaments, colonies, or even multicellular) Absorb, photosynthesize, or ingest food 1 m KINGDOM: Plants r Vulpes, a red fox KINGDOM: Animals Certain algae, mosses, ferns, conifers, and flowering plants Multicellular, usually with specialized tissues, containing complex cells Photosynthesize food Sponges, worms, insects, fishes, frogs, turtles, birds, and mammals Multicellular with specialized tissues containing complex cells Ingest food Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. (Protist): © Michael Abby/Visuals Unlimited; (Plant): © Pat Pendarvis; (Fungi): © Rob Planck/Tom Stack; (Animal): © Royalty-Free/Corbis

22.  Binomial nomenclature (two-word names)- used to assign each organism with two part name e.g. Homo Sapience  Universal  Latin-based ◦ First word represents genus of organism e.g. Homo ◦ Second word is specific epithet of a species within the genus e.g. Sapience ◦ Always italicized as a Genus species (Homo sapiens) ◦ Genus may be abbreviated e.g. Escherichia Coli as E. Coli 22

23. 23 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Some plants within a population exhibit variation in leaf structure. Deer prefer a diet of smooth leaves over hairy leaves. Plants with hairy leaves reproduce more than other plants in the population. Generations later, most plants within the population have hairy leaves, as smooth leaves are selected against.

24.  Population - Members of a species within an area  Community - A local collection of interacting populations  Ecosystem – A community plus its physical environment  How chemicals are cycled and re-used by organisms  How energy flows, from photosynthetic plants to top predators 24

25. 25 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. WASTE MATERIAL, DEATH, AND DECOMPOSITION heat solar energy Chemical cycling Energy flow heat

26. 26 1975 Minimal coral death b. a. Healthy coral reef 1985 Some coral death with no fish present 1995 Coral bleaching with limited chance of recovery 2004 Coral is black from sedimentation; bleaching still evident Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a: © Frank & Joyce Burek/Getty Images; b (All): © Dr. Phillip Dustan

27.  Humans modify ecosystems ◦ Humans negative impact on ecosystems:  Destroy forest or grassland for agriculture, housing, industry, etc.  Produce waste and contaminate air, water, etc.  However, humans depend upon healthy ecosystems for ◦ Food ◦ Medicines ◦ Raw materials ◦ Other ecosystem processes 27

28.  Biodiversity is the zone of air, land, and water where organisms exist ◦ Abundance of species estimated about 15 million. ◦ The variability of their genes, and ◦ The ecosystems in which they live  Extinction is: ◦ The death of the last member of a species ◦ Estimates of 400 species/day lost worldwide 28

29.  Scientific method is a standard series of steps in gaining new knowledge through research. ◦ Begins with observation  Scientists use their five senses e.g. use visual sense to observe animal behavior  Instruments can extend the range of senses e.g. use microscope to see microorganisms  Take advantage of prior studies ◦ Hypothesis  A tentative explanation for what was observed  Developed through inductively reasoning from specific to general 29

30. 30 Observation New observations are made, and previous data are studied. Hypothesis Input from various sources is used to formulate a testable statement. Conclusion The results are analyzed, and the hypothesis is supported or rejected. Scientific Theory Many experiments and observations support a theory. Experiment/Observations The hypothesis is tested by experiment or further observations. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Courtesy Leica Microsystems Inc.

31.  Experimentation ◦ Purpose is to challenge the hypothesis ◦ Designed through deductively reasoning from general to specific ◦ Often divides subjects into a control group and an experimental group ◦ Predicts how groups should differ if hypothesis is valid  If prediction happens, hypothesis is unchallenged  If not, hypothesis is unsupportable 31

32.  The results are analyzed and interpreted  Conclusions are what the scientist thinks caused the results  Findings must be reported in scientific journals  Peers review the findings and the conclusions  Other scientists then attempt to duplicate or dismiss the published findings 32

33.  Results or Data ◦ Observable, objective results from an experiment ◦ Strength of the data expressed in probabilities ◦ The probability that random variation could have caused the results  Low probability (less than 5%) is good  Higher probabilities make it difficult to dismiss random chance as the sole cause of the results 33

34.  Scientific Theory: ◦ Joins together two or more related hypotheses ◦ Supported by broad range of observations, experiments, and data  Scientific Principle / Law: ◦ Widely accepted set of theories ◦ No serious challenges to validity 34

35.  Experimental (Independent) variable ◦ Applied one way to experimental group ◦ Applied a different way to control group  Response (dependent) variable ◦ Variable that is measured to generate data ◦ Expected to yield different results in control versus experimental group 35

36.  Observations: ◦ Nitrate fertilizers boost grain crops, but may damage soils by altering its properties ◦ When grain crops are rotated with pigeon pea it adds natural nitrogen  Hypothesis: ◦ Pigeon pea rotation will boost crop production as much as nitrates ◦ Pigeon pea rotation will NOT damage soils 36

37. 37 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Dr. Jeremy Burgess/Photo Researchers, Inc. nodules

38.  Experimental Design ◦ Control Group  Winter wheat planted in pots without fertilizer ◦ Experimental Groups  1-Winter wheat planted in pots with 45 kg/ha nitrate  2-Winter wheat planted in pots with 90 kg/ha nitrate  3-Winter wheat planted in pots that had grown a crop of pigeon peas ◦ All groups treated identically except for above 38

39. 39 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. = Pigeon pea/winter wheat rotation 15 20 10 5 0 year 1year 2year 3 = no fertilization treatment = 45 kg of nitrogen/ha Control Pots Test Pots = 90 kg of nitrogen/ha Wheat Biomass (grams/pot) b. Results a. Control pots and test pots of three types Test pots 90 kg of nitrogen/ha Test pots Pigeon pea/winter wheat rotation Control pots no fertilization treatment Test pots 45 kg of nitrogen/ha (All): Courtesy Jim Bidlack

40.  Experimental Prediction: ◦ Wheat production following pigeon pea rotation will be equal or better than following nitrate fertilizer  Results ◦ 45 kg/ha produced slightly better than controls ◦ 90 kg/ha produced nearly twice as much as controls ◦ Pigeon pea rotation did not produce as much as the controls 40

41.  Conclusion ◦ Research hypothesis was not supported by results ◦ However, research hypothesis was not proven false by negative results  Revised experiment ◦ Grow wheat in same pots for several generations ◦ Look for soil damage in nitrate pots and improved production in pigeon pea pots 41

42.  Results ◦ After second year:  Production following nitrates declined  Production following pigeon pea rotation was greatest of all ◦ After third year  Pigeon pea rotation produced 4X as much as controls  Revised conclusions ◦ Research hypothesis supported ◦ Pigeon pea rotation should be recommended over nitrates 42

43.  Defining Life - Emergent Properties ◦ Materials and Energy ◦ Reproduction and Development ◦ Adaptations and Natural Selection  Biosphere Organization ◦ Human Population ◦ Biodiversity  Classification  The Scientific Method 43