Biology, 9th ed,Sylvia Mader Chapter 01 Chapter 01 A View of Life A View of Life

Biology, 9th ed,Sylvia Mader Outline Chapter 01 A View of Life Defining Life - Emergent Properties Materials and Energy Reproduction and Development Adaptations and Natural Selection Biosphere Organization Human Population Biodiversity Classification The Scientific Method

Living things vs. nonliving objects: Defining Life (1) Living things vs. nonliving objects: Comprised of the same chemical elements Obey the same physical and chemical laws The cell is the smallest, most basic unit of all life Familiar organisms are multicellular Some cells independent – single-celled organisms

Defining Life

Emergent Properties – Biological organization Defining Life (2) Emergent Properties – Biological organization Levels range from extreme micro to global Each level up: More complex than preceding level Properties: A superset of preceding level’s properties Emerge from interactions between components

Levels of Biological Organization

Living Things: Acquire & Process Food Energy - the capacity to do work The sun: Ultimate source of energy for nearly all life on Earth Drives photosynthesis Metabolism - all the chemical reactions in a cell Homeostasis - Maintenance of internal conditions within certain boundaries

Acquiring Nutrients

Living Things: Respond to Stimuli Living things detect changes in environment Response often involves movement Vulture can detect and find carrion a mile away Monarch butterfly senses fall and migrates south Microroganisms follow light or chemicals Even leaves of plants follow sun Responses collectively constitute behavior

Living Things: Reproduce and Develop Organisms live and die Must reproduce to maintain population Multicellular organisms: Begins with union of sperm and egg Developmental instructions encoded in genes Composed of DNA Long spiral molecule in chromosomes

Rockhopper Penguins & Offspring

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

Organization of the Biosphere Population - Members of a species within an area Community - A local collection of interacting populations Ecosystem - The communities in an area considered with their physical environment How chemicals are cycled and re-used by organisms How energy flows, from photosynthetic plants to top predators

Terrestrial Ecosystems: A Grassland

Marine Ecosystems: A Coral Reef

Human Populations Ecosystems negatively impacted by human populations Destroyed for agriculture, housing, industry, etc. Degraded and destabilized by pollution However, humans depend upon healthy ecosystems for Food Medicines Raw materials Other ecosystem processes

Biodiversity Biodiversity: Extinction: The total number of species (est. 15 million) The variability of their genes, and The ecosystems in which they live Extinction: The death of the last member of a species Estimates of 400 species/day lost worldwide

Classification Taxonomy: The rules for identifying and classifying organisms 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 usually includes more species than the level below it, and fewer species than the one above it

Levels of Classification Taxon Human Corn Domain Eukarya Eukarya Kingdom Animalia Plantae Phylum Chordata Anthophyta Class Mammalia Liliopsida Order Primates Commelinales Family Hominidae Poacae Genus Homo Zea Species H. sapiens Z. mays

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

Domains: The Archaea

Domains: The Bacteria

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

Domains: The Eukaryote Kindoms

Binomial nomenclature (two-word names) Universal Latin-based Scientific Names Binomial nomenclature (two-word names) Universal Latin-based First word represents genus of organism Second word is specific epithet of a species within the genus Always Italicized asa Genus species (Homo sapiens) Genus may occur alone (Homo), but not specific epithet

The Scientific Method: Observation and Hypothesis Begins with observation Scientists use their five senses Instruments can extend the range of senses Hypothesis A tentative explanation for what was observed Developed through inductively reasoning from specific to general

The Scientific Method: A Flow Diagram

The Scientific Method: 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

The Scientific Method: Results 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

The Scientific Method: Conclusion and Review 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

Scientific Principle / Law: Scientific Theory 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

Controlled Experiments: The Variables 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 groups

Controlled Experiments: Observation & Hypotheses Observations: Nitrate fertilizers boost grain crops, but may damage soils 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

Root Nodules

Controlled Experiments: 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

Crop Rotation Study

Controlled Experiments: Results 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

Controlled Experiments: Conclusion & Revision 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

Controlled Experiments: Revised Results & Conclusion 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

A Field Study

Biology, 9th ed,Sylvia Mader Review Chapter 01 A View of Life Defining Life - Emergent Properties Materials and Energy Reproduction and Development Adaptations and Natural Selection Biosphere Organization Human Population Biodiversity Classification The Scientific Method

Biology, 9th ed,Sylvia Mader Chapter 01 Ending Slide Chapter 01 A View of Life A View of Life