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

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

Ecosystems The biosphere Organisms Populations Communities Cells Organelles Molecules Tissues Organs and organ systems Cell 1 µm Atoms 10 µm 50 µm

LE 1-4 Sunlight Ecosystem Heat Chemical energy Consumers (including animals) Producers (plants and other photosynthetic organisms)

LE 1-6 Sperm cell Nuclei containing DNA Egg cell Fertilized egg with DNA from both parents Embryo’s cells With copies of inherited DNA Offspring with traits inherited from both parents

LE 1-7 DNA double helixSingle strand of DNA Nucleotide Cell Nucleus DNA

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Two Main Forms of Cells Characteristics shared by all cells: – Enclosed by a membrane – Use DNA as genetic information Two main forms of cells: – Eukaryotic – Prokaryotic

LE 1-8 Membrane Cytoplasm EUKARYOTIC CELL PROKARYOTIC CELL DNA (no nucleus) Membrane 1 µm Organelles Nucleus (contains DNA)

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Feedback Regulation in Biological Systems Regulatory systems ensure a dynamic balance in living systems Chemical processes are catalyzed (accelerated) by enzymes Many biological processes are self-regulating: the product regulates the process itself

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings In negative feedback, the accumulation of a product slows down the process itself In positive feedback (less common), the product speeds up its own production Animation: Negative Feedback Animation: Negative Feedback Animation: Positive Feedback Animation: Positive Feedback

LE 1-11 Enzyme 1 A A B B C C D D D D D D D D D D D Enzyme 2 Enzyme 3 Negative feedback Enzyme 1

LE 1-12 W Enzyme 4 W X X Y Y Z Z Z Z Z Z Z Z Z Z Enzyme 5 Enzyme 6 Positive feedback Enzyme 4 Enzyme 6 Enzyme 5 Z Z Z Z Z Z Z Z Z

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Biologists have named about 1.8 million species Estimates of total species range from 10 million to over 200 million

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 into a hierarchical order Ursidae Ursus Carnivora Mammalia Chordata Animalia Eukarya Ursus americanus (American black bear)

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 (prokaryotes) – Archaea (prokaryotes) – Eukarya (eukaryotes)

LE 1-15a Bacteria 4 µm

LE 1-15b 100 µm Protists

LE 1-15c Kingdom Plantae

LE 1-15d 0.5 µm Archaea

LE 1-15e Kingdom Fungi

LE 1-15f Kingdom Animalia

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Unity in the Diversity of Life Underlying life’s diversity is a striking unity, especially at lower levels of organization In eukaryotes, unity is evident in details of cell structure Cilia of windpipe cells Cilia of Paramecium

LE 1-16b Cilia of windpipe cells Cilia of Paramecium Cross section of cilium, as viewed with an electron microscope 0.1 µm

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Concept 1.4: Evolution accounts for life’s unity and diversity The history of life is a saga of a changing Earth billions of years old

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The evolutionary view of life came into sharp focus in 1859, when Charles Darwin published On the Origin of Species by Natural Selection

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Origin of Species articulated two main points: – Descent with modification (the view that contemporary species arose from a succession of ancestors) – Natural selection (a proposed mechanism for descent with modification)

Evolution of adaptations in the population Differences in reproductive success Overproduction and competition Population of organisms Hereditary variations Darwin’s Observations

LE 1-21a Population with varied inherited traits Natural selection can “edit” a population’s heritable variations

LE 1-21b Elimination of individuals with certain traits

LE 1-21c Reproduction of survivors

LE 1-21d Increasing frequency of traits that enhance survival and reproductive success

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Bat wings are an example of adaptation Video: Soaring Hawk Video: Soaring Hawk

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Tree of Life Biologists often show evolutionary relationships in a treelike diagram Phylogenetic Tree Large ground finch Large cactus ground finch Sharp-beaked ground finch Geospiza magnirostris Geospiza conirostris Medium ground finch Geospiza fuliginosa Small ground finch Woodpecker finch Camarhynchus psittacula Large tree finch Medium tree finch Cactus ground finch Geospiza difficilis Cactus flower eaters Geospiza scandens Seed eater Ground finches Seed eaters Tree finches Common ancestor from South American mainland Insect eaters Bud eater Warbler finches Mangrove finch Geospiza fortis Cactospiza pallida Small tree finch Camarhynchus pauper Camarhynchus parvulus Green warbler finch Gray warbler finch Certhidea olivacea Certhidea fusca Vegetarian finch Platyspiza crassirostris Cactospiza heliobates

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Inquiry is a search for information and explanation, often focusing on specific questions Two main processes of scientific inquiry: – Discovery science: describing nature – Hypothesis-based science: explaining nature

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Types of Data Two types of data: – Quantitative data: numerical measurements – Qualitative data: recorded descriptions

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Hypothesis-Based Science In science, inquiry usually involves proposing and testing hypotheses Hypotheses are hypothetical explanations

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 A hypothesis is an explanation on trial, making a prediction that can be tested

LE 1-25a Hypothesis #1: Dead batteries Hypothesis #2: Burnt-out bulb Observations Question

LE 1-25b Hypothesis #1: Dead batteries Hypothesis #2: Burnt-out bulb Test prediction Test falsifies hypothesis Prediction: Replacing batteries will fix problem Prediction: Replacing bulb will fix problem Test prediction Test does not falsify hypothesis

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

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Myth of the Scientific Method The scientific method is an idealized process of inquiry Very few scientific inquiries adhere rigidly to the “textbook” scientific method

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Limitations of Science The limitations of science are set by its naturalism – Science seeks natural causes for natural phenomena – Science cannot support or falsify supernatural explanations, which are outside the bounds of science

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Theories in Science A scientific theory is much broader than a hypothesis A scientific theory is: – broad in scope – generally enough to generate new hypotheses – supported by a large body of evidence

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Culture of Science Science is an intensely social activity Both cooperation and competition characterize scientific culture

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Science, Technology, and Society The goal of science is to understand natural phenomena Technology applies scientific knowledge for some specific purpose

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings A set of themes connects the concepts of biology – Science as a Process – Evolution – Energy Transfer – Continuity and Change – Relationship of Structure and Function – Regulation – Interdependence in Nature – Science, Technology, and Society

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