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Characteristics of Life

Characteristics of Life. Chapter 1. Organization and Cells. All living things are made up of one ( unicellular ) or more cells ( multicellular ). Cell - smallest unit capable of performing all life’s processes. . Organization and Cells . Living organisms have organization.

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Characteristics of Life

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  1. Characteristics of Life Chapter 1

  2. Organization and Cells • All living things are made up of one (unicellular) or more cells (multicellular). • Cell- smallest unit capable of performing all life’s processes.

  3. Organization and Cells • Living organisms have organization. • Organization- high degree of order within an organism’s internal and external parts and its interaction with the living world. • Highest level of organization- organism is made up of organ systems that carry out specific functions within the organism (Ex: digestive system).

  4. Organization and Cells

  5. Response to Stimuli (Responsiveness) • Living things respond to a stimulus. • Stimulus- physical or chemical changes in an organism’s internal or external environment. • This is essential to survival.

  6. Homeostasis • Homeostasis- maintenance of a stable internal environment despite the constant changing of an organisms external environment. • Organisms have built in system that maintains stable internal conditions, such as: • Temperature • Water content • Nutrient uptake by cell

  7. Homeostasis

  8. Metabolism • Energy is required to power ALL life’s processes, such as • Growth and development • Movement • Repair • Metabolism- sum of all the chemical reactions that take in and transform energy and materials from the environment.

  9. Metabolism • Photosynthesis • Plants, algae, phytoplankton, and some bacteria capture and use the sun’s energy to make sugar molecules. • Organisms that cannot make their own food must get their food from other organisms.

  10. Growth and Development • Nonliving things (Ex: icicles) grow by accumulating more of the same material (Ex: ice) of which they are made. • LIVING things grow through division and enlargement of cells. • Living multicellular organisms mature through cell division, cell enlargement, and development.

  11. Growth and Development • Development- process by which organisms become more adult. • Involves: cell division, cell differentiation, or specialization. • Your body contains trillions of specialized cells (Ex: nerve cells, blood cells, skin cells..), all of which originated from a single cell, the fertilized egg.

  12. Reproduction • Reproduction- Organisms produce more organisms like themselves. • NOT needed for individual’s survival. However, reproduction is ESSENTIAL to survival of a species. • Hereditary information is passed from parent to offspring through DNA. Short segments of DNA make up individual genes.

  13. Reproduction • Two major types of reproduction: • Sexual reproduction- hereditary information recombines from TWO organisms. Offspring are similar but not identical to either parent. • Ex: Frogs • Asexual reproduction- herditary information comes from a single parent organism. Offspring are identical to parent. • Ex: bacteria

  14. Evolution • The basic GENETIC characteristics of an individual organism do not change over their lifetime. • Populations of organisms DO change through time, or evolve. • This is critical to survival in a changing world. • Explains the diversity of life-forms we see on Earth today.

  15. Themes in Biology

  16. Diversity and Unity of Life • Living things come in many varieties (huge diversity).

  17. Diversity and Unity of Life • Although diverse, living things are characterized by unity, or things they have in common. • Genetic code- rules governing how cells use hereditary information. • Organelles that carry out life’s functions.

  18. Diversity and Unity of Life • “Tree of Life”- a model of the relationships by ancestry among organisms. • Living things share certain genes, yet no two types of organisms share all the same genes. • Three main lineages, called domains. Organisms found on closer branches (lineages) have more similar sets of genes. • Bacteria • Archaea • Eukarya - complex cells containing a nucleus. Less complex cells

  19. Diversity and Unity of Life • Another system of grouping organisms divides life into six categories called kingdoms. • 4 kingdoms within domain Eukarya • Kingdoms Animalia, plantae, fungi, protista • 1 kingdom within domain Archaea • Kingdom Archaea • 1 kindom within domain Bacteria • Kingdom Bacteria

  20. Tree of Life

  21. Interdependence of Organisms • Ecology- study of how organisms interact with each other and the environment. • Study single species as well as ecosystems. • Ecosystems- communities of species and their physical environment. • Studies have shown that species depend on each other and their physical environment for survival.

  22. Evolution of Life • Evolution- (decent with modification) process in which inherited characteristics within POPULATIONS change over generations. • Can lead to genetically distinct populations and development of new species.

  23. Evolution of Life • Theory of Evolution by Natural Selection • Natural Selection- organisms with certain favorable traits survive and reproduce more than those without them. • Those traits that increase an organism’s ability to survive and reproduce are called adaptations.

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