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Study of Biology

Discover the essence of biology, the study of life and all living organisms. From the origin of life forms to the complexity of cells, genetic codes, and the characteristics of living things, delve into the fascinating world of biology. Uncover the mechanisms of growth, reproduction, and organization that define life on Earth, and learn how cells, tissues, organs, and systems work together to sustain life. Explore the diversity of unicellular and multicellular organisms, and understand the importance of genetic codes in the development and repair of living organisms.

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Study of Biology

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  1. Study of Biology

  2. A. What is Biology? (Bio = life, logy = the study of; biology = the study of life) • Modern scientists have been unable to agree upon a single definition of life. However, most biologists characterize life by the functions that living things perform; such as getting food, removing wastes, etc

  3. 1. Def – Biology is the study of all living things • 2. Living things are called organisms • a. Organisms include bacteria, fungi, protists, plants, and animals

  4. 3. First life forms arose on Earth more than 3.5 billion years ago • a. Single-celled, microscopic organisms (living thing) appeared first & floated alone in seas • 4. Over 40 million species (types of organisms) exist with only about 2 million identified • 5. Many organisms are unidentified & new species are still discovered

  5. All Living Things Share Common Characteristics • Basic Unit is the Cell • They Reproduce • All Based On Universal Genetic Code (DNA) • Grow & Develop

  6. Common Characteristics • Obtain & Use Materials & Energy • Respond To Their Environment • Maintain A Stable Internal Environment • AS A GROUP, Living Things Evolve, That Is They Change Over Time

  7. B. The Characteristics of Life • 1. Life has organization • a. Atoms • b. Molecules • c. Organelles • (1) specialized structures within the cell • (2) ie.nucleus, cell membrane, ribosomes • d. Cells • (1) The basic unit of structure and function is the cell • (2) All organisms are made up of cells • (3) All cells contain cytoplasm and are surrounded by a cell membrane

  8. All Organisms are made of Cells

  9. Facts About Cells • Cells are the smallest living unit of an organism • All cells contain living material called cytoplasm • All cells are surrounded by a cell membrane that controls what enters & leaves the cell

  10. More Cell Facts • Cells are complex & highly organized • Cells have parts called organelles that do different jobs e.g. Chloroplasts in plants make sugars

  11. (4) Prokaryotes vs. Eukaryotes • (a) Prokaryotic organisms are the simplest cells. Do not have a nucleus or membrane-bound organelles. (Bacteria) • (b) Eukaryotic organisms are more complex. Have a nucleus and membrane bound organelles. (Plants, Animals, Fungi) • http://dsc.discovery.com/tv-shows/other-shows/videos/assignment-discovery-shorts-first-cells.htm

  12. More Cell Facts • The simplest cells are called Prokaryotes • These cells DO NOT have a nucleus or membrane-bound organelles • Bacteria are examples

  13. More Cell Facts • More complex cells are called Eukaryotes • These cells DO have a nucleus and membrane-bound organelles • Plants, animals, & fungi are examples

  14. (5) Unicellular organisms – made up of one cell • (6) Multicellular organisms – made up of two or more cells

  15. Organisms are Grouped by their Number of Cells • Unicellular Organisms • Living Organism Made Up Of One Cell • Multicellular Organisms • Living Organism Made Up Of Many, Specialized Cells

  16. Life is Organized on Several Levels

  17. In multicellular organisms, cells and groups of cells (tissues) are organized by their function Cells  tissues Tissues organs Organs systems

  18. Levels • Atoms • Molecules • Organelles • Cells – life starts here • Tissues • Organs • System • Organism

  19. e. Tissues • (1) Groups of cells that perform similar functions (ligaments, tendons, mesophyll) • f. Organs • (1) Groups of tissues that perform similar functions (stomach, brain, lungs) • g. Organ Systems • (1) Groups of organs that perform similar functions (digestive, muscular, nervous) • h. Organism • (1) Groups of organ systems (humans, trees, worms)

  20. Levels • Population • Community • Ecosystem • Biosphere

  21. 2. Life Reproduces • a. Sexual Reproduction • (1) Involves two parents • (2) Egg fertilized by the sperm to produce a zygote • (3) Offspring different from the parents • b. Asexual Reproduction • (1) involves one parent • (2) Cell divides • (3) Offspring identical to the parent

  22. Organisms Reproduce to Pass on their Genetic Traits

  23. Sexual Reproduction Involves 2 parents Egg fertilized by sperm to make a ZYGOTE Offspring DIFFERENT from parents Two Types of Reproduction

  24. Asexual Reproduction Involves a single organism or cell Cell divides Offspring IDENTICAL to parent Two Types of Reproduction

  25. 3. All Life has a Genetic Code • a. DNA (deoxyribose nucleic acid) • (1) All organisms contain DNA • (2) Codes for the proteins that make up the cell and perform the life functions • http://dsc.discovery.com/tv-shows/other-shows/videos/assignment-discovery-shorts-first-cells.htm

  26. Cells Have a Genetic Code

  27. Genetic Code • DNA (deoxyribose nucleic acid) carries the genetic code for all organisms • All organisms contain DNA • DNA codes for the proteins that make up cells & do all the work

  28. 4. Life Grows for Development and Repair • a. Cells grow by producing more cells and by growing in size • b. Organisms develop as they mature into adult organisms

  29. Organisms Grow & Develop

  30. Growth & Development • Cells grow by producing MORE CELLS & by cell ENLARGEMENT • Organisms develop as they mature into an adult organism

  31. Cells Require Food & Energy

  32. 5. Life Acquires Materials and Energy (Metabolism) • a. Food (1) Autotrophs – can make their own food • (a) Photoautotrophs use the sunlight to make their own food • (b) Chemoautotrophs use chemical (such as iron and sulfur) for their energy

  33. (2) Heterotrophs – cannot make their own food; they must consume other organisms • (a) Herbivores – eat plants • (b) Carnivores – eat animals • (c) Omnivores – eat both plant and animals

  34. b. Metabolism (1) Sum of all the chemical reactions in an organism (2)All require energy (3) Sunlight is the ultimate energy for life on Earth

  35. Metabolism (4)Cellular Respiration a. Cells releasing the chemical energy stored in foods 6O2 + C6H12O6 6CO2 + 6H2O

  36. 6. Organisms Respond to Stimuli a. Organisms Respond to Temperature, Water, Food Supplies, etc. In Order To Survive & Reproduce

  37. b. Homeostasis (1) def. - Keeping The Internal Environment Of The Cell or Organism Within The Ranges Required For Life (2) Stable internal conditions of pH, temperature, water balance, etc.

  38. (3) A disruption in any organism system will result in a corresponding disruption of homeostasis • (4) Feedback Mechanisms • (a) Occurs when the level of one substance influences the level of another substance or activity of another organ • (b) Feedback mechanisms have evolved in living things as a mechanism by which they maintain homeostasis

  39. (5) Examples of Maintaining Homeostasis in Living Things • (a) Blood Sugar Regulation • - The pancreas is an endocrine gland which produces hormones which regulate blood glucose (sugar) levels • - Insulin is a hormone that is released by the pancreas when blood sugar level is too high • - Insulin lowers blood sugar in two major ways • 1. It takes the glucose into our cells to be used as fuel in cell respiration from our blood • 2. Converts excess glucose to glycogen (animal starch) and stores it in our liver and muscles • - Glucagon - Released by cells in the pancreas when blood sugar levels are too low; converts stored glycogen to glucose into the blood to be transported throughout the body • The failure to maintain blood glucose homeostasis results in diabetes and sometimes death.

  40. http://www.bing.com/videos/search?q=diabetes&view=detail&mid=EFC211B4C87FBD6214CCEFC211B4C87FBD6214CC&first=21&adlt=stricthttp://www.bing.com/videos/search?q=diabetes&view=detail&mid=EFC211B4C87FBD6214CCEFC211B4C87FBD6214CC&first=21&adlt=strict • http://sciencestage.com/v/27797/diabetes-type-2-what-is-diabetes-mellitus?.html • http://health.discovery.com/videos/diabetes-high-low-blood-sugar.html

  41. (b) Plant leaf regulation of water balance • Stomata – small openings in the leaves of plants; Allow water vapor and gases to enter and leave the leaf • Guard Cells – surround the stomata and control the size • Changes in the stomata controlled by guard cells regulate the rate of water loss and gas exchange in many plants

  42. Plants need to regulate water loss and carbon dioxide intake for photosynthesis and other life activities • When plants do not keep enough water in their cells, they wilt and die

  43. (c) Temperature Regulation • - Humans maintain a relatively constant body temperature of about 37° C. • when we "heat up" we sweat if possible • the evaporation of this perspiration returns the body to its original temperature

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