Biology 9/15-10/21 (6 weeks) 授課老師:蔡玉真 電話分機: 2468, 2469 生命科學系 107室 Office time: Tuesday 1:00-3:00

Neil A.Campbell and Jane B.Reece Biology Seventh edition Neil A.Campbell and Jane B.Reece Exploring life (1) The cell (6-10) The chemistry of life (2-5) Bird’s nest fern (Fiddlehead fern)

mid-term exam (2): 70% Quiz: 20% 出席率: 10% Score: 33.3分

Exploring Life Chapter 1 Biology is the scientific study of life How do we recognize life? By what ? Growth Reproduce similar organisms

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

A Hierarchy of Biological Organization: Biologists explore life from the microscopic to the global scale A Hierarchy of Biological Organization: microscope scale of molecules and cells organisms the global scale of the entire living planet

many levels of biological organization biosphere Ecosystems Livings and non-living communities livings population organisms from the biosphere to organisms

Organs and organ systems From cells to molecules Organelles 1 µm Molecules Cells Atoms Tissues 10 µm 50 µm Organs and organ systems

The cell is the lowest level of organization that can perform all activities required for life DNA spindle mitosis cell division cell

Cell theory: All cells share certain characteristics They are all enclosed by a membrane They all use DNA as genetic information There are two main forms of cells Eukaryotic Prokaryotic nuclear cell

Nucleus (contains DNA) Eukaryotic cells vs. Prokaryotic cells EUKARYOTIC CELL Membrane Cytoplasm Organelles Nucleus (contains DNA) 1 µm PROKARYOTIC CELL DNA (no nucleus) cell size membrane-enclosed organelles Lack of membrane-enclosed organelles

The Cell’s Heritable Information : DNA -program the cells’ production of proteins -transmit information from parents to offspring inheritance Egg cell Sperm cell Nuclei containing DNA Fertilized egg with DNA from both parents Embyro’s cells with copies of inherited DNA Offspring with traits inherited from DNA

The molecular structure of DNA Deoxyribonucleic acid (DNA) four types of nucleotides (A, T, C, and G). DNA double helix DNA Cell Nucleotide A C T G Nucleus Single strand of DNA. DNA

Energy flows through an ecosystem Producers (plants and other photosynthetic organisms) Consumers (including animals) Sunlight Chemical energy Heat Ecosystem ecosystem Usually entering as sunlight and exiting as heat

Taxonomy: Classifying life similarity diversity Species Genus Family Order Class Phylum Kingdom Domain Ursus ameri-canus (American black bear) Ursus Ursidae Carnivora Mammalia Chordata Animalia similarity diversity Community Eukarya

The Three Domains of Life At the highest level, life is classified into three domains Bacteria Archaea Eukarya Consist of prokaryotes the eukaryotes Includes the various protist kingdoms and the kingdoms Plantae, Fungi, and Animalia

Life’s three domains protist Plantae, Animalia Fungi 4 µm 100 µm DOMAIN ARCHAEA 0.5 µm Animalia Fungi 0.5µm

Remarkable unity in the Diversity of Life Cilia of windpipe cells. The cells that keep the lungs clean by moving a film of debris-trapping mucus upward. Cross section of cilium, as viewed with an electron microscope Cilia of Paramecium. 9+2 The cilia of Paramecium propel the cell through pond water. Universal genetic language: DNA Eukaryotic cell structure

The evolutionary view of life Charles Darwin published On the Origin of Species by Natural Selection (in 1859) Charles Darwin organism

The Origin of Species articulated two main points Descent with modification -mutation -sexual reproduction Natural selection Gametes get different combination of parents chromosomes

Natural selection environmental factors 1 Populations with varied inherited traits environmental factors 2 Elimination of individuals with certain traits. 3 Reproduction of survivors. 4 Increasing frequency of traits that enhance survival and reproductive success.

Natural Selection Population of organisms Overproduction Hereditary and struggle for existence Hereditary variations Differences in reproductive success Evolution of adaptations in the population

The Tree of life Kinship food niche Galapagos islands similar anatomical features Large ground finch Small ground finch Geospiza magnirostris Seed eater Sharp-beaked ground finch Camarhynchus psitacula Green warbler finch Large tree finch Large cactus Ground finches Tree finches Insect eaters Bud eater Warbler finches Common ancestor from South American mainland Gray warbler finch Certhidea olivacea Certhidea fusca difficilis Cactus flower eater Geospiza scandens conirostris fortis Medium ground Geospiza fuliginosa Mangrove finch Cactospiza heliobates Cactospiza pallida Woodpecker Medium tree finch Camarhynchus pauper Small tree finch Vegetarian finch Camarhynchus parvulus Platyspiza crassirostris Cactus ground finch Kinship food niche Galapagos islands

The products of natural selection Are often exquisite adaptations of organisms to the special circumstances of their way of life and their environment bat Structure and function

Reductionism vs. System biology reducing complex systems to simpler components that are more manageable to study System biology - models of the dynamic behavior of whole biological systems at the cellular and molecular levels high-throughput technology, bioinformatics, and interdisciplinary research teams

How do biologists inquiry to explore life? A search for information and explanation, often focusing on specific questions Two approaches of scientific study: Discovery science : describe nature Hypothesis-based science: explain nature to know

Discovery Science--Descriptive science -describes life (at many different levels) -careful observation and measurement -analysis of data and get conclusions Example: “All organisms are made of cells” Induction reasoning generalizations based on a large number of specific observations

Hypotheses-based Scientific method Observations Questions Hypothesis # 1: Dead batteries Hypothesis # 2: Burnt-out bulb Prediction: Replacing batteries will fix problem Replacing bulb Test prediction Test does not falsify hypothesis Test falsifies hypothesis testable falsifiable Propose Test specific questions

Logic of Hypothesis-Based Science deductive The logic flows from the general to the specific If a hypothesis is correct, Then we can expect a particular outcome

Designing Controlled Experiments control groups experimental groups in a way that cancels the effects of unwanted variables

Scientific method Discovery Science : induction Hypotheses-based Science: deduction Limitation? Observation and experimental results: repeatability Hypothesis is testable and falsifiable

Is broad in scope than hypothesis Theories : Is broad in scope than hypothesis Generates new hypotheses Is supported by a large body of evidence Model : Diagrams, graphs, 3-D objects, computer programs or mathematical equations Help us understand scientific phenomena and make predictions Models of ideas, structures, and processes

In mimicry A harmless species resembles a harmful species Advantage? Flower fly (non-stinging) Honeybee (stinging) Advantage?

Field Experiments with Artificial Snakes To test this mimicry hypothesis Field Experiments with Artificial Snakes (a) Artificial king snake (b) Brown artificial snake that has been attacked hundreds of artificial snakes an experimental group a control group

Range of scarlet king snake Range of eastern color snake The hypothesis predicts that predators in non–coral snake areas will attack king snakes more frequently than will predators that live where coral snakes are present Scarlet king snake Key Range of scarlet king snake Range of eastern color snake Eastern coral snake North Carolina South Carolina

After a given period of time The researchers collected data that fit a key prediction In areas where coral snakes were present, most attacks were on artificial brown snakes 17% 83% North Carolina South Carolina X In areas where coral snakes were absent, most attacks were on artificial king snakes 84% 16% Key % of attacks on artificial king snakes % of attacks on brown artificial snakes Field site with artificial snakes

Welcome to Biology

Protein interaction map: Outer membrane and cell surface CELL Cytoplasm Nucleus System biology

The negative feedback regulation An accumulation of an end product slows the process that produces that product A A Enzyme 1 Enzyme 1 shut down/shut-off B B Enzyme 2 C C Enzyme 3 D D D D D D end product D D D D D The negative feedback regulation

The positive feedback regulation The end product speeds up production W W Enzyme 4 Enzyme 4 X X Enzyme 5 Enzyme 5 Y Y Enzyme 6 Enzyme 6 Z Z Z Z Z Z Z Z Z Z Z Z Z end product Z Z Z Z Z Z The positive feedback regulation