2-1 Characteristics of Living Things

1. 2-1 Characteristics of Living Things

2. Made of one or more units called cells

3. 2. Reproduce

4. 3. Grow and Develop

5. Obtain and use energy

6. 5. Respond to their environment

7. #1 Living things are made up of cells • Cell – small self contained unit • Can perform all the functions of life

8. Unicellular – organism made of one cell • Multicellular – organism made of many cells

9. Cells are only found in living material or material that was once alive

10. #2 Living things Reproduce • Produce organisms like themselves

11. Sexual reproduction – 2 cells formed from different individuals unite to form an organism

12. Asexual Reproduction – single

13. #3 – Living things grow and develop • Are capable of growth at one stage of their life cycle at least • Development – cycle of growth

14. Aging – comes at the end of development • Organism becomes less efficient at the process of life

15. #4 – Living things obtain and use energy • Energy from their environment or surroundings • Energy to grow, develop, and reproduce

16. Metabolism = Anabolism + Catabolism

17. Anabolism – putting together or synthesizing complex substances from simpler substances

18. Plants – photosynthesis • Animals – take in energy  food

19. Catabolism – final breakdown of complex substances into simpler substances resulting in the release of energy

20. #5 – Living Things respond to their environment • Slow – changes in metabolic processes • Rapid – changes in behavior

21. Stimulus – anything that causes an organism to react • Irritability – the ability of living things to react to stimuli

22. Living things respond to stimuli in a way that improves their chances for survival

23. Homeostasis • Organisms ability to maintain constant or stable conditions that are necessary for life • Process by which organisms respond to different stimuli • Homeo – same • Stasis – stopping/standing

25. 2-2 Biology: The Study of Life

26. Biology – the study of life • Biologist – person who studies living things

27. Branches of Biology • Many divisions • Molecular biologist • Cell biologist • Zoologist (animals) • Botanist (plants) • Paleontologists • Ecologists • Global Ecologists

29. Questions at the …. • Molecular level • Cellular level • Multicellular level • Population level • Global level

30. Tools of a Biologist

32. To study small organisms  microscopes • Produces a larger image

33. Compound Light Microscope • Most common • Can observe living organisms • Light passes through the organism • Two types of lenses – Objectives – 2 • Ocular (eyepiece)

34. Total Magnification = • Ocular x Objective

36. Limit of Resolution • Beyond this point objects become blurry and detail is lost – will always exist • Increase magnification – more and more detail until you reach the limit of resolution

38. Staining • Colors some parts of the cell to make them clearly visible

40. Types of Microscopes • Compound light microscope • Electron microscope

41. Electron Microscope

42. Electron Microscope • Can see smaller things than the compound • Uses electromagnets to bend electrons • Two types – SEM and TEM

43. TEM (Transmission) • How it works – shine a beam of electrons at a sample and magnify the image onto a florescent screen (TV)

44. SEM – Scanning • How it works – beam of electrons scans back and forth across the surface of a specimen • Electrons bounce off the specimen are picked up by detectors and a 3-D image is formed

47. Limitations of Electron Microscopes • Specimens must be in a vacuum (no air) • Thin slices • Stained, dried out or dead

48. Laboratory Techniques of a Biologist

49. Centrifugation • Cell fractionation – cells blended in a blender • Broken bits spun 20,000x a minute