Unit 1: Chemical Basis of Life

1. Unit 1: Chemical Basis of Life

2. Unit 1A: Characteristics of Living Things Biology is the scientific study of living things Another word for a living thing is an organism. Although the many types of organisms may appear to be different from one another, they all share common characteristics.

3. Part A- 8 Important Characteristics of Living Things: Are made up of cells Are based on a universal genetic code Reproduce Grow and develop Respond to their environment Maintain a stable internal environment Taken as a group, evolve Obtain and use materials and energy

4. Can you think of a characteristic that living things and non-living things have in common? • They are made up of ATOMS & MOLECULES

5. 1. Living Things are Made up of Cells Cell- basic unit of all forms of life

6. 1. LIVING THINGS ARE MADE UP OF CELLS (CONT) Multicellular Unicellular Made up of more than 1 cell Cells must work together to accomplish the organism’s life processes Made of only 1 cell Must accomplish all life activities within one cell Clown Fish (Euk) Bacteria (prok) Euglena (Euk)

7. 2. Living Things are based on a Universal Genetic Code • What is the genetic code of all organisms? • DNA (deoxyribonucleic acid) • What does it do? Why is it an important necessary part of every cell? • DNA is the genetic material of the cell which contains codes for the building of proteins. • Proteins contribute to our traits!

8. 2. Living Things are based on a Universal Genetic Code (cont) • A segment of DNA that codes for a specific protein is called a gene • The reason different cells in the same organism can have a different structure and function even though they all have the same DNA (genes) is because different genes are being used in these different cells. A specific cell will have certain genes turned on while other genes are turned off.

9. 3. LIVING THINGS REPRODUCE • The process of reproduction ensures that DNA is passed from parent(s) to offspring • Is reproduction necessary for the survival for the individual or the species? • Species!

10. Two Types of Reproduction Asexual Sexual 3. LIVING THINGS REPRODUCE (CONT) Involving a single parent cell Offspring are genetically identical to the parent Suitable for a stable environment Involves joining 2 parent cells Offspring have variations compared to parents and other offspring Suitable for a changing environment

11. 3. LIVING THINGS REPRODUCE (CONT) Examples: • Either method of reproduction has the potential to be very successful - depending on the species and its environment. Typically bacteria (unicellular) Less common but possible in multicellular organisms. Typical method for animals, plants, some fungi and protists.

12. 3. LIVING THINGS REPRODUCE (CONT)

13. 4. Living things grow and develop Growth Development • Both growth and development take place as an organism matures. • How would you differentiate between these 2 processes? • Getting Larger • Size • Height • Weight • Changing Features • Ex: Butterfly life cycle or Puberty

14. 5. Living Things Respond To Their Environment • Stimulus • A signal to which and organism responds • Response • A specific reaction to a stimulus

15. Examples: 5. Living Things Respond To Their Environment (cont) Directions: Label each of these examples - put an "S" by the stimulus and an "R" by the response: b) A blowfish becomes larger and extends is spikes when it is threatened by a predator. a) When you touch something hot you pull your hand away.

16. 5. Living Things Respond To Their Environment (cont) What other examples can you think of?

17. 6. LIVING THINGS MAINTAIN A STABLE INTERNAL ENVIRONMENT • When organisms maintain relatively constant or stable internal conditions we call this homeostasis. • These conditions must be maintained within certain limits regardless of any internal or external changes. • Example: regulation of body temperature • When its cold humans --- • When its hot, we ---- • We want to maintain our body temp around 98.6°F

18. 6. LIVING THINGS MAINTAIN A STABLE INTERNAL ENVIRONMENT (CONT) • Another Example of Homeostasis: • Blood pH should be around 7.4 • Various molecules called buffers work to keep your blood at the correct pH

19. 7. LIVING THINGS,TAKEN AS A GROUP, EVOLVE Evolution: Change of organisms over time Natural selection: the process by which organisms that have traits that make them better able to survive in their environment will be more successful at reproducing and therefore pass these traits on to future generations.

20. 7. LIVING THINGS, TAKEN AS A GROUP, EVOLVE (CONT) • What will happen to the population of these beetles over time? Why?

21. 7. LIVING THINGS, TAKEN AS A GROUP, EVOLVE (CONT) How do the new traits (variations) that are “selected for” by natural selection arise in organisms? (Where do these new traits or variations come from)? Changes in the DNA (mutations) during reproduction can lead to adaptations in the offspring.

22. 8. LIVING THINGS OBTAIN AND USE MATERIALS & ENERGY Materials and energy move between the living (biotic) and nonliving (abiotic) parts of the ecosystem

23. 8. LIVING THINGS OBTAIN AND USE MATERIALS & ENERGY (CONT) • Organisms must be able to • Produce or obtain nutrients (like food and water) • Convert the nutrients into a usable form of chemical energy called ATP • Use these forms of energy to power their life processes • All living things fit into one of two categories based on how they produce or obtain nutrients.

24. 8. LIVING THINGS OBTAIN AND USE MATERIALS & ENERGY (CONT) Heterotrophs (consumers) Autotrophs (producers) Obtains food by consuming other living things Ex: Animals, fungi, bacteria Capture energy from sunlight or chemicals and use it to produce their own food Ex: All Plants, bacteria

25. 8. LIVING THINGS OBTAIN AND USE MATERIALS & ENERGY (CONT) • Photosynthesis is the process used by autotrophs to convert carbon dioxide and water into carbohydrates using energy from the sun. • What is the purpose of photosynthesis? • To make food molecules

26. 8. LIVING THINGS OBTAIN AND USE MATERIALS & ENERGY (CONT) The food is then used to build the structure of the organism and make cellular energy (ATP- energy that cells can use to power their processes).

27. 8. LIVING THINGS OBTAIN AND USE MATERIALS & ENERGY (CONT) • Cellular respiration • Process that releases energy by breaking down glucose and other food molecules in the presence of oxygen. • Cellular Respiration can be summarized by the following chemical equation: • What is the purpose of cellular respiration? • To turn food molecules into ATP IMPORTANT: All organisms undergo cellular respiration!

28. 8. LIVING THINGS OBTAIN AND USE MATERIALS & ENERGY (CONT) Put the words “photosynthesis” and “cellular Respiration” in the correct blank on the diagram.

29. How are photosynthesis and cellular respiration related???? 8. LIVING THINGS OBTAIN AND USE MATERIALS & ENERGY (CONT) The products of one reaction become the reactants of the other. In other words, each reaction makes what the other reaction needs.

30. 8. LIVING THINGS OBTAIN AND USE MATERIALS & ENERGY (CONT) • The combination of all of your chemical reactions is called your metabolism • When metabolism stops, An organism CANNOT perform life functions  DEATH 

31. ONE LAST FEATURE OF LIVING THINGS All living things must die Life Span- How long an organism lives

33. We can’t live forever! • Over time there is damage to DNA and cells • Cannot always maintain homeostasis in all environmental conditions • Earth has a limited supply of resources when organisms die the materials in their cells are recycled back into the environment for use by new generations of living things

34. Part B- Classification of Organisms • Taxonomy- The Science of Classification • Involves grouping and naming organisms • Carolus Linnaeus- • Binomial nomenclature- classification system in which each species is assigned a two-part scientific name. • The first word is called the Genus. • The second word is called the species (often a descriptive word, such as a color or physical patterning).

35. Species: • A group of similar organisms that can breed and produce fertile offspring

36. Linnaeus placed organisms into larger more general groups based on characteristics.

37. Linnaean Taxonomic Categories • The 7 major categories in classifying organisms, from most general to least general (most specific) are: • Kingdom • Phylum • Class • Order • Family • Genus • Species K P C O F G S

38. Grizzly and Black Bear

39. 1.Of the following, the broadest (most general) classification category is A. class B. phylum C. genus D. order 2.Two organisms classified in the same class must be in the same A. phylum B. family C. order D. genus

40. 3.Two organisms classified in the same class could be in the same A. genus B. order C. family D. all of these 4.Of the following, Rana catesbiana is most closely related to A. Rana pipiens B.Homo sapiens C.Xenopus laevis D. Felis domesticus 5.Of the following, the correct order from largest, most general group, to smallest, most specific group, is A. species, genus, family, class, order C. class, order, family, genus, species B. species, family, genus, class, order D. class, genus, order, family, species

41. 6 Kingdoms of Living Things

42. VIRUSES: ALIVE or NOT? There is some debate over whether viruses are living or nonliving. Most agree that they are nonliving. Why? They are unable to INDEPENDENTLY carry out all life processes They are particles made of DNA & proteins that can replicate only by infecting living cells. Do not belong to any kingdom and don't contain any cells.

43. Explain why someone would think viruses are considered living things based on the 8 characteristics of life. Influenza