Chapter 1 Biology Exploring Life 1 Outline l

Chapter 1 Biology: Exploring Life 1

Outline l Defining Life - Emergent Properties l Materials and Energy l Reproduction and Development l Adaptations and Natural Selection l Classification l Organization and Diversity l Natural Selection 2

Outline l l Biosphere Organization l Human Population l Biodiversity The Scientific Method l Observation l Hypothesis l Data l Conclusion l Scientific Theory 3

Defining Life l Living things: l Comprised of the same chemical elements e. g. Carbon, Hydrogen, and Oxygen l Obey the same physical and chemical laws l 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 l Cells are produced from preexisting cells l Cells are the smallest units that perform all vital physiological functions l 4

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

Defining Life l Emergent properties: In life’s hierarchy of organization, new properties emerge at each level l Levels range from extreme micro (e. g. Atoms, Molecules and Cells) to global (e. g. Community, Ecosystem and Biosphere) l Each level of organization is more complex than the previous level. 6

Levels of Biological Organization Copyright © The Mc. Graw-Hill Companies, Inc. Permission required for reproduction or display. 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 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 7

Atom Molecule Organelle Cell -> Tissue Organ system Organism Population Community Ecosystem Biosphere. 8

Living Things: Acquire & Process Food l Energy – required to maintaining organization and conducting life-sustaining processes l The sun: l Ultimate source of energy for nearly all life on Earth l Certain organisms, such as plants, capture solar energy to carry on photosynthesis l l l 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. l Homeostasis - Maintenance of internal conditions within certain boundaries 9

Acquiring Nutrients Copyright © The Mc. Graw-Hill Companies, Inc. Permission required for reproduction or display. food a. d. e. b. c. a: © Niebrugge Images; b: © Photodisc Blue/Getty Images; c: © Charles Bush Photography; d: © Michael Abby/Visuals Unlimited; e: © Pat Pendarvis; f: National Park Service Photo f. 10

Living Things: Respond to Stimuli l Living things interact with the environment and respond to changes in the environment l Response ensures survival of the organism and it often results movement l l Vulture can detect and find the dead animal a mile away and fly toward the dinner. l Monarch butterfly senses approach of fall and migrates south l Microorganisms can sense light or chemicals l Even leaves of plants follow sun Activities as a result of Responses are termed behavior 11

Living Things: Reproduce and Develop l Organisms live and die l All living organisms must reproduce to ensure continued existence and maintain population l In most multicellular organisms reproduction: l Begins with union of sperm and egg (fertilization) l Followed by cell division and differentiation l Developmental instructions encoded in genes l Composed of DNA l Long spiral molecule in chromosomes 12

Rockhopper Penguins & Offspring Copyright © The Mc. Graw-Hill Companies, Inc. Permission required for

Living Things: Adapt to Change l Adaptation l Any modification that makes an organism more suited to its way of life l Organisms become modified over long period time l l Respond to environmental changes by developing new adaptations However, organisms very similar at basic level l Suggests living things descended from same ancestor l Descent with modification - Evolution l Caused by natural selection 14

Evolution, the Unifying Concept of Biology l l Despite diversity, organisms share the same basic characteristics l Composed of cells organized in a similar manner l Their genes are composed of DNA l Carry out the same metabolic reactions to acquire energy This suggests that they are descended from a common ancestor 15

Classification l Taxonomy: l Discipline of identifying and classifying organisms according to certain rules l Hierarchical levels (taxa) based on hypothesized evolutionary relationships l Levels are, from least inclusive to most inclusive: l Species, genus, family, order, class, phylum, kingdom, and domain l 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) 16

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Levels of Classification 18

Domains l Bacteria l l l Microscopic unicellular prokaryotes Archaea l Bacteria-like unicellular prokaryotes l Extreme aquatic environments Eukarya l Eukaryotes – Familiar organisms 19

Domains 20

Evolutionary Tree of Life Copyright © The Mc. Graw-Hill Companies, Inc. Permission required for reproduction or display. BACTERIA common ancestor (first cells) ARCHAEA Protists Photosynthetic protist Plants cell with nucleus EUKARYA Fungi Heterotrophic Protist common ancestor Past Animals Present Time 21

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Domains: The Archaea Copyright © The Mc. Graw-Hill Companies, Inc. Permission required for reproduction or display. • Prokaryotic cells of various shapes • Adaptations to extreme environments • Absorb or chemosynthesize food • Unique chemical characteristics Methanosarcina mazei, an archaeon 1. 6 m © Ralph Robinson/Visuals Unlimited 23

Domains: The Bacteria Copyright © The Mc. Graw-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. 5 m © A. B. Dowsett/SPL/Photo Researchers, Inc. 24

Kingdoms l Archaea – Kingdoms still being worked out l Bacteria - Kingdoms still being worked out l Eukarya l Kingdom Protista l Kingdom Fungi l Kingdom Plantae l Kingdom Animalia 25

Domains: The Eukaryote Kingdoms Copyright © The Mc. Graw-Hill Companies, Inc. Permission required for reproduction or display. Protists KINGDOM: Plants • Algae, protozoans, 1 m • Certain algae, mosses, ferns, slime molds, and water molds • Complex single cell (sometimes filaments, colonies, or even multicellular) • Absorb, photosynthesize, or ingest food conifers, and flowering plants • Multicellular, usually with specialized tissues, containing complex cells • Photosynthesize food r Paramecium, a unicellular protozoan KINGDOM: Animals KINGDOM: Fungi • Sponges, worms, insects, • Molds, mushrooms, yeasts, fishes, frogs, turtles, birds, and mammals • Multicellular with specialized tissues containing complex cells • Ingest food and ringworms • Mostly multicellular filaments with specialized, complex cells • Absorb food 1 Coprinus, a shaggy mane mushroom Vulpes, a red fox (Protist): © Michael Abby/Visuals Unlimited; (Plant): © Pat Pendarvis; (Fungi): © Rob Planck/Tom Stack; (Animal): © Royalty-Free/Corbis 26

Scientific Names l Binomial nomenclature (two-word names)- used to assign each organism with two part name e. g. Homo Sapience l Universal l Latin-based l First word represents genus of organism e. g. Homo l Second word is specific epithet of a species within the genus e. g. Sapience l Always italicized as a Genus species (Homo sapiens) l Genus may be abbreviated e. g. Escherichia Coli as E. Coli 27

Natural Selection Copyright © The Mc. Graw-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. 28

Organization of the Biosphere l Population an area - Members of a species within l Community - A local collection of interacting populations l Ecosystem – A community plus its physical environment l How chemicals are cycled and re-used by organisms l How energy flows, from photosynthetic plants to top predators 29

Terrestrial Ecosystems: A Grassland Copyright © The Mc. Graw-Hill Companies, Inc. Permission required for reproduction or display. heat solar energy heat heat WASTE MATERIAL, DEATH, AND DECOMPOSITION Chemical cycling Energy flow 30

Marine Ecosystems: Coral Reef Copyright © The Mc. Graw-Hill Companies, Inc. Permission required for reproduction or display. a. Healthy coral reef 1975 Minimal coral death b. 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 a: © Frank & Joyce Burek/Getty Images; b (All): © Dr. Phillip Dustan 31

Human Populations l Humans modify ecosystems l l Humans negative impact on ecosystems: l Destroy forest or grassland for agriculture, housing, industry, etc. l Produce waste and contaminate air, water, etc. However, humans depend upon healthy ecosystems for l Food l Medicines l Raw materials l Other ecosystem processes 32

Biodiversity l l Biodiversity is the zone of air, land, and water where organisms exist l Abundance of species estimated about 15 million. l The variability of their genes, and l The ecosystems in which they live Extinction is: l The death of the last member of a species l Estimates of 400 species/day lost worldwide 33

The Scientific Method l Scientific method is a standard series of steps in gaining new knowledge through research. l l Begins with observation l Scientists use their five senses e. g. use visual sense to observe animal behavior l Instruments can extend the range of senses e. g. use microscope to see microorganisms l Take advantage of prior studies Hypothesis l A tentative explanation for what was observed l Developed through inductively reasoning from specific to general 34

The Scientific Method: A Flow Diagram Copyright © The Mc. Graw-Hill Companies, Inc. Permission required for reproduction or display. Observation New observations are made, and previous data are studied. Hypothesis Input from various sources is used to formulate a testable statement. Experiment/Observations Conclusion The hypothesis is tested by experiment or further observations. The results are analyzed, and the hypothesis is supported or rejected. Scientific Theory Many experiments and observations support a theory. Courtesy Leica Microsystems Inc. 35

Steps in the Scientific Method 36

The Scientific Method: Experimentation l Experimentation Purpose is to challenge the hypothesis l Designed through deductively reasoning from general to specific l Often divides subjects into a control group and an experimental group l Predicts how groups should differ if hypothesis is valid l If prediction happens, hypothesis is unchallenged l If not, hypothesis is unsupportable l 37

The Scientific Method l The results are analyzed and interpreted l Conclusions are what the scientist thinks caused the results l Findings must be reported in scientific journals l Peers review the findings and the conclusions l Other scientists then attempt to duplicate or dismiss the published findings l Results or Data: Observable, objective results from an experiment. 38

Scientific Theory l Scientific Theory: l Joins together two or more related hypotheses l Supported by broad range of observations, experiments, and data l Scientific Principle / Law: l Widely accepted set of theories l No serious challenges to validity 39

l Control is the portion that you are not performing experiments on. It is just there for comparison purpose. l Variable is any factor, trait, or condition that is differing in an experiment. l The independent variable is the one that is changed by the scientist. l The dependent variable is the variable that you measure or observe. 40

Review l l Defining Life - Emergent Properties l Materials and Energy l Reproduction and Development l Adaptations and Natural Selection Biosphere Organization l Human Population l Biodiversity l Classification l The Scientific Method 41