Plants and Animals – Common Challenges

1. Plants and Animals – Common Challenges Chapter 27

2. Impacts, IssuesA Cautionary Tale • A multicelled organism must keep conditions inside its body within a range cells can tolerate; Korey Stringer died from heat stroke after football practice on a hot, humid day

3. Introduction to Anatomy and Physiology • Anatomy • The study of body form (structures) • Physiology • The study of how body parts are put to use (function)

4. 27.1 Levels of Structural Organization • Tissue • One or more cell types (and often extracellular matrix) that collectively perform a specific task • Organ • Two or more tissues in specific proportions that interact to carry out a specific task • Organ system • Organs that interact in one or more tasks

5. Growth Versus Development • Growth • An increase in number, size, and volume of cells (quantitative) • Development • A series of stages in which specialized tissues, organs and organ systems form in heritable patterns (qualitative)

6. Evolution of Form and Function • All anatomical and physiological traits have a genetic basis and have been affected by natural selection • Plants and animals adapted to life on dry land with structures to move gases and retain moisture

7. Anatomy of a Tomato Plant

8. Flower, a reproductive organ Cross-section of a leaf, an organ of photosynthesis and gas exchange shoot system (aboveground parts) root system (belowground parts, mostly) Cross-section of a stem, an organ of structural support, storage, and distribution of water and food Fig. 27-2, p. 462

9. The Human Respiratory System

10. Ciliated cells and mucus-secreting cells of a tissue that lines respiratory airways Organs (lungs), part of an organ system (the respiratory tract) of a whole organism Lung tissue (tiny air sacs) laced with blood capillaries— one-cell-thick tubular structures that hold blood, which is a fluid connective tissue Fig. 27-3, p. 463

11. The Internal Environment • Plant and animal cells are surrounded by their internal environment: extracellular fluid (ECF) • To keep cells alive, body parts work together to keep the internal environment within tolerable limits (homeostasis)

12. A Body’s Tasks • Essential functions of plants and animals: • Maintain favorable conditions for cells • Acquire and distribute water, nutrients and other raw materials, and dispose of wastes • Defend against pathogens • Reproduce • Nourish and protect gametes and embryos

13. 27.1 Key Concepts Many Levels of Structure and Function • Cells of plants and animals are organized in tissues • Tissues make up organs, which work together in organ systems • This organization arises as the plant or animal grows and develops • Interactions among cells and among body parts keep the body alive

14. 27.2 Common Challenges • Although plants and animals differ in many ways, they share some common challenges

15. Animation: Morphology of a tomato plant

16. Gas Exchange • Diffusion • Ions or molecules of a substance move from a place where they are concentrated to one where they are scarce • Aerobic respiration • The pathway that releases energy from food or photosynthetic products using oxygen and releasing carbon dioxide

17. Internal Transport • Very small organisms can exchange materials with the environment by diffusion; larger organisms have vascular tissues • Plants have xylem and phloem • Animals have a circulatory system with blood vessels

18. Internal Transport

19. Maintaining the Water-Solute Balance • Passive transport • A material moves in or out of ECF down its concentration gradient through a transport protein • Active transport • A protein pumps one specific solute from a region of lower concentration to a region of higher concentration (requires energy)

20. Cell-to-Cell Communication • Specialized cells release signal molecules that help control and coordinate events in the body • Growth • Development • Maintenance • Reproduction

21. Variations in Resources and Threats • Each habitat has a specific set of resources (water, nutrients, light, temperature) and challenges (predators, pathogens, parasites) • Competition and variation in these factors promotes diversity of form and function

22. Forms of Protection

23. 27.2 Key ConceptsSimilarities Between Animals and Plants • Animals and plants exchange gases with their environment, transport materials through their body, maintain volume and composition of their internal environment, and coordinate cell activities • They also respond to threats and to variations in available resources

24. 27.3 Homeostasis in Animals • Detecting and responding to changes is a characteristic trait of all living things and the key to homeostasis

25. Three Components Maintain Homeostasis in Animals

26. STIMULUS Sensory input into the system Receptor such as a free nerve ending in the skin Integrator such as the brain or the spinal cord Effector a muscle or a gland Fig. 27-7, p. 466

27. Negative Feedback • Negative feedback mechanisms • A change leads to a response that reverses that change • Example: A furnace turns off and on to maintain a set temperature; similar mechanisms maintain human body temperature

28. Homeostatic Controls of Human Body Temperature

29. STIMULUS Body’s surface temperature skyrockets after exertion on a hot, dry day. Integrator Effectors Receptors Pituitary gland and thyroid gland trigger adjustments in activity of many organs. Hypothalamus (a brain region) compares input from receptors against a set point for the body. Sensory receptors in skin and elsewhere detect the change in temperature. RESPONSE Different types of effectors carry out specific (not general) responses: Effectors Body’s surface temperature falls, which causes sensory receptors to initiate shift in effector output. Skeletal muscles in chest wall contract more frequently; faster breathing speeds heat transfer from lungs to air. Blood vessels in skin expand as muscle in their wall relaxes; more metabolic heat gets shunted to skin, where it dissipates into the air. Sweat gland secretions increase; the evaporation of sweat cools body surfaces. Adrenal gland secretions drop off; excitement declines. Effectors collectively call for an overall slowdown in activities, so the body generates less metabolic heat. Fig. 27-8a, p. 466

30. STIMULUS Body’s surface temperature skyrockets after exertion on a hot, dry day. Integrator Effectors Receptors Pituitary gland and thyroid gland trigger adjustments in activity of many organs. Hypothalamus (a brain region) compares input from receptors against a set point for the body. Sensory receptors in skin and elsewhere detect the change in temperature. RESPONSE Different types of effectors carry out specific (not general) responses: Effectors Body’s surface temperature falls, which causes sensory receptors to initiate shift in effector output. Skeletal muscles in chest wall contract more frequently; faster breathing speeds heat transfer from lungs to air. Blood vessels in skin expand as muscle in their wall relaxes; more metabolic heat gets shunted to skin, where it dissipates into the air. Sweat gland secretions increase; the evaporation of sweat cools body surfaces. Adrenal gland secretions drop off; excitement declines. Effectors collectively call for an overall slowdown in activities, so the body generates less metabolic heat. Stepped Art Fig. 27-8a, p. 466

31. dead, flattened skin cell sweat gland pore Fig. 27-8b, p. 466

32. Animation: Control of human body temperature

33. Positive Feedback • Positive feedback mechanisms • A chain of events intensifies the change from the original condition, leading to a change that ends feedback • Example: Childbirth contractions

34. 27.4 Heat-Related Illness • Heat stroke is a failure of homeostasis that can cause irreversible brain damage or death • Symptoms: dizziness, blurred vision, muscle cramping, weakness, nausea and vomiting • Risk factors: Sweating, heat and humidity, age, medical condition, pregnancy • First aid: Water, ice packs, call for medical aid

35. 27.5 Does Homeostasis Occur in Plants? • Mechanisms that control homeostasis in plants are not centrally controlled • Systemic acquired resistance: Affected cells release signaling molecules that cause release of protective organic compounds • Compartmentalization walls injured and infected tissues with resins and toxic compounds

36. Compartmentalization Response

37. A Strong B Moderate C Weak Fig. 27-9, p. 468

38. Animation: Compartmentalization responses

39. Sand, Wind, and Yellow Beach Lupine • Lupine adaptations to beach environment: • Nitrogen-fixing bacteria provide nutrients • Hairs trap moisture that evaporates from stomata • Leaves fold in hot, windy conditions

40. Rhythmic Leaf Folding • Circadian rhythm • A biological activity pattern in plants or animals that recurs with a 24-hour cycle • Example: Rhythmic leaf folding might help reduce heat loss at night

41. Rhythmic Leaf Folding

42. 1 A.M. 6 A.M. Noon 3 P.M. 10 P.M. Midnight Fig. 27-11, p. 469

43. Animation: Rhythmic leaf movements

44. 27.3-27.5 Key Concepts Homeostasis • Homeostasis is the process of keeping conditions in the body’s internal environment stable • The feedback mechanisms that often play a role in homeostasis involve receptors that detect stimuli, an integrating center, and effectors that carry out responses

45. 27.6 How Cells Receive and Respond to Signals • Communication among distant body cells requires special molecules that travel through ECF, blood, or plant vascular systems • Signal reception • Signal transduction • Cellular response • Example:Apoptosis (programmed cell death)

46. Three Steps in Signaling

47. Signal Reception Signal Transduction Cellular Response Signal binds to a receptor, usually at the cell surface. Binding brings about changes in cell properties, activities, or both. Changes alter cell metabolism, gene expression, or rate of division. Fig. 27-12a, p. 470

48. Signal Transduction Pathway

49. Signal to die docks at receptor. Signal leads to activation of protein-destroying enzymes. Fig. 27-12b, p. 470

50. Apoptosis