campbell_1.ppt chapter 1 exploring life.
- 1. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero Chapter 1 Exploring Life
- 2. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Overview: Biology’s Most Exciting Era • Biology – Is the scientific study of life • The phenomenon we call life – Defies a simple, one-sentence definition • We recognize life – By what living things do
- 3. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Some properties of life Figure 1.2 (c) Response to the environment (a) Order (d) Regulation (g) Reproduction (f) Growth and development (b) Evolutionary adaptation (e) Energy processing
- 4. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Unifying Themes • The study of life reveals common themes: – Organization – Information – Energy and Matter – Interactions – Evolution
- 5. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • From the biosphere to organisms 1 The biosphere: the parts of the earth inhabited by life A Hierarchy of Biological Organization •The hierarchy of life extends through many levels of biological organization (2) Ecosystems: all the Iiving things in a particular area, along with the nonliving components of the environment with which life interacts (3) Communities: the living part of an ecosystem (4) Populations: all the individuals of a species living in a specified area (5) Organisms: individual living things • The study of life extends from the microscope scale of molecules and cells to the global scale of the entire living planet
- 6. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings A Hierarchy of Biological Organization • From cells to molecules Cell 8 Cells 6 Organs and organ systems: a body part composed of more than one tissues and carrying out a particular function 7 Tissues: an integrated group of cells with a common function, structure 10 Molecules 9 Organelles 50 µm 10 µm 1 µm Atoms Figure 1.3
- 7. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Biological systems are more than the sum of their parts • A system – Is a combination of components that form a more complex organization • Due to increasing complexity – New properties emerge with each step upward in the hierarchy of biological order • These emergent properties are – due to the arrangement and interactions of parts as complexity increases For example, although photosynthesis occurs in an intact chloroplast, it will not take place in a disorganized test-tube mixture of chlorophyll and other chloroplast molecules
- 8. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Reductionism and Systems Biology • Reductionism – Involves reducing complex systems to simpler components that are more manageable to study • Systems biology – Seeks to create models of the dynamic behavior of whole biological systems • With such models – Scientists will be able to predict how a change in one part of a system will affect the rest of the system
- 9. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Structure and function are correlated at all levels of biological organization
- 10. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings A Closer Look at Cells • The cell – Is the lowest level of organization that can perform all activities required for life 25 µm Figure 1.5
- 11. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Theme: Expression and Transmission of Genetic Information • Cells contain chromosomes made partly of DNA, the substance of genes – Which program the cells’ production of proteins and transmit information from parents to offspring 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 both parents Figure 1.6
- 12. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • The molecular structure of DNA – Accounts for its information-rich nature DNA Cell Nucleotide A C T A T A C C G G T A T A (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). (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. Figure 1.7 Nucleus
- 13. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Genome: The entire “library” of genetic instructions that an organism inherits. Genomics: The systematic study of whole sets of genes (or other DNA) and their interactions within a species, as well as genome comparisons between species. Proteome: The entire set of proteins expressed by a given cell or group of cells. Proteomics: The systematic study of sets of proteins and their properties, including their abundance, chemical modifications and interactions. Genomics, Proteomics
- 14. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Theme: Energy and Matter • The dynamics of any ecosystem include two major processes – Cycling of nutrients, (for example, materials acquired by plants eventually return to the soil) – The flow of energy from sunlight to producers to consumers
- 15. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Energy flows through an ecosystem – Usually entering as sunlight and exiting as heat Producers (plants and other photosynthetic organisms) Consumers (including animals) Sunlight Chemical energy Heat Heat Ecosystem Figure 1.4
- 16. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Theme: Interactions in Biological Systems • Each organism – Interacts with its environment • Both organism and environment – Are affected by the interactions between them • Interactions between two species can be beneficial for both species (e. g. interactions between some fungi and plants), or sometimes one species benefits and the other is harmed (e. g. one animal can eat another animal) • Organisms interact continuously with physical factors in their environment (e. g. leaves absorb light from the sun, roots break up rocks)
- 17. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Intermolecular Interactions and Feedback Regulation • Interactions between molecules is crucial for life (e. g. enzymes, hormones) • Intermolecular interactions are responsible for regulation • A kind of supply-and-demand economy – Applies to some of the dynamics of biological systems • In feedback regulation – The output, or product, of a process regulates that very process
- 18. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • In negative feedback – An accumulation of an end product slows the process that produces that product B A C D Enzyme 1 Enzyme 1 Enzyme 2 Enzyme 3 D D D D D D D D D D C B A Negative feedback Figure 1.11
- 19. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • In positive feedback – The end product speeds up production W W X Y Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Y X Enzyme 4 Enzyme 5 Enzyme 6 Enzyme 4 Enzyme 5 Enzyme 6 Positive feedback Figure 1.12
- 20. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Theme: Evolution, Unity and Diversity of Life Biologists explore life across its great diversity of species •Diversity is a hallmark of life Biologists have so far identified and named about 1.8 million species
- 21. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Grouping Species: The Basic Idea • Taxonomy – Is the branch of biology that names and classifies species according to a system of broader and broader groups
- 22. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Classifying life Species Genus Family Order Class Phylum Kingdom Domain Mammalia Ursus ameri- canus (American black bear) Ursus Ursidae Carnivora Chordata Animalia Eukarya Figure 1.14
- 23. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Three Domains of Life • At the highest level, life is classified into three domains – Bacteria – Archaea – Eukarya • Domain Bacteria and domain Archaea – Consist of prokaryotes • Domain Eukarya, the eukaryotes – Includes the various protist kingdoms and the kingdoms Plantae, Fungi, and Animalia
- 24. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Life’s three domains Figure 1.15 100 µm 0.5 µm 4 µm Bacteria are the most diverse and widespread prokaryotes and are now divided among multiple kingdoms. Each of the rod-shaped structures in this photo is a bacterial cell. 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 protists into several kingdoms that better represent evolution and diversity. Kingdom Plantae consists of multicellula eukaryotes that carry out photosynthesis, the conversion of light energy to food. 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 photo shows a colony composed of many cells. Kindom Fungi is defined in part by the nutritional mode of its members, such as this mushroom, which absorb nutrientsafter decomposing organic material. Kindom Animalia consists of multicellular eukaryotes that ingest other organisms. DOMAIN ARCHAEA
- 25. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Unity in the Diversity of Life • 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. Figure 1.16
- 26. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • Evolution accounts for life’s unity and diversity • The history of life – Is a saga of a changing Earth billions of years old • Darwin articulated two main points – Descent with modification – Natural selection
- 27. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Tree of Life • Darwin proposed that natural selection – Could enable an ancestral species to “split” into two or more descendant species, resulting in a “tree of life” 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 finch Ground finches Tree finches Insect eaters Bud eater Warbler finches Common ancestor from South American mainland Gray warbler finch Certhidea olivacea Certhidea fusca Geospiza difficilis Cactus flower eater Geospiza scandens Seed eater Geospiza conirostris Geospiza fortis Medium ground finch Geospiza fuliginosa Mangrove finch Cactospiza heliobates Cactospiza pallida Woodpecker finch Medium tree finch Camarhynchus pauper Small tree finch Vegetarian finch Camarhynchus parvulus Platyspiza crassirostris Cactus ground finch Figure 1.23
- 28. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • 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
- 29. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Discovery Science • Discovery science – Describes natural structures and processes as accurately as possible through careful observation and analysis of data • Data – Are recorded observations – Can be quantitative or qualitative
- 30. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Induction in Discovery Science • In inductive reasoning – Scientists derive generalizations based on a large number of specific observations
- 31. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Hypothesis-Based Science • In science, inquiry that asks specific questions – Usually involves the proposing and testing of hypothetical explanations, or hypotheses
- 32. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Role of Hypotheses in Inquiry • In science, a hypothesis – Is a tentative answer to a well-framed question, an explanation on trial – Makes predictions that can be tested
- 33. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings 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
- 34. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings A Closer Look at Hypotheses in Scientific Inquiry • A scientific hypothesis must have two important qualities – It must be testable – It must be falsifiable • We can never prove that a hypothesis is true. Testing a hypothesis in various ways, producing different sorts of data, can increase our confidence in it tremendously, but no amount of experimental testing can prove a hypothesis beyond a shadow of doubt.
- 35. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • In mimicry – A harmless species resembles a harmful species Flower fly (non-stinging) Honeybee (stinging) Figure 1.26 A Case Study in Scientific Inquiry: Investigating Mimicry in Snake Populations
- 36. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • In this case study – Mimicry in king snakes is examined – 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 Scarlet king snake Key Range of scarlet king snake Range of eastern color snake Eastern coral snake North Carolina South Carolina Figure 1.27
- 37. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Field Experiments with Artificial Snakes • To test this mimicry hypothesis – Researchers made hundreds of artificial snakes, an experimental group resembling king snakes and a control group of plain brown snakes (a) Artificial king snake (b) Brown artificial snake that has been attacked Figure 1.28
- 38. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings • After a given period of time – The researchers collected data that fit a key prediction Figure 1.29 In areas where coral snakes were present, most attacks were on artificial brown snakes Key % of attacks on artificial king snakes % of attacks on brown artificial snakes Field site with artificial snakes 17% 83% North Carolina South Carolina X X X X X X X XX X X X X X In areas where coral snakes were absent, most attacks were on artificial king snakes 84% 16% Key
- 39. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Designing Controlled Experiments • Experiments must be designed to test – The effect of one variable by testing control groups and experimental groups in a way that cancels the effects of unwanted variables