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Defining Life (1)

Defining Life (1). How do you know if something is alive? What are properties of living things that non-livings things do no possess? What is the smallest living thing you can think of?. 1. So what is required of life?. Living “things” are:. 2. Defining Life (1).

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Defining Life (1)

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  1. Defining Life (1) How do you know if something is alive? What are properties of living things that non-livings things do no possess? What is the smallest living thing you can think of? 1

  2. So what is required of life? Living “things” are: 2

  3. 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

  4. Defining Life

  5. Levels of Biological Organization

  6. 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

  7. Acquiring Nutrients

  8. 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

  9. 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

  10. Rockhopper Penguins & Offspring

  11. 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

  12. So what is required of life? • Living “things” • eat • give off wastes • reproduce • breathe • die • respond to their environment • adapt • contain heritable material

  13. 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

  14. Terrestrial Ecosystems:A Grassland

  15. Marine Ecosystems:A Coral Reef

  16. Classification What kinds of music do you listen to? What kinds of music are there? 16

  17. 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

  18. 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

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

  20. Domains:The Archaea

  21. Domains:The Bacteria

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

  23. Domains:The Eukaryote Kindoms

  24. Scientific Names • Binomial nomenclature (two-word namess) • 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

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