Attributes of Life (Chapter 19)

1. Attributes of Life (Chapter 19) • Introduction to life • Themes/Characteristics of all living organisms • Cardinal structural and functional “nuts and bolts” of all life

2. Introduction • What defines life? • Irritability (particularly after a test!) • Grows spontaneously (as in first year of college and old age) • Reproduce • Some exceptions • Ice grows • Mule (donkey x horse) but does not reproduce • Defining life • Multiple definitions all with multiple perspectives • Best to focus on what are themes or general features

3. What is Life?Chapter 23 • Introduction to life • Themes/Characteristics of all living organisms • Cardinal structural and functional “nuts and bolts” of all life

4. Themes/Characteristics • Hierarchy theory and emergent properties • Structure and function: “it is the cell, stupid” • Continuity of life based on information: “it is your genes, stupid” (not jeans) • Openness of biological systems • Regulatory capacity of living systems • Capacity to reproduce • Capacity to utilize energy • Diversity and similarity of living systems • Evolution of living systems

5. Take-Home Messages - Themes • Hierarchical nature of the living world • Emergent properties of living systems • Cell as a basic unit of structure and function • Continuity of life based on information • Openness of biological systems • Regulatory capacity of living systems: homeostasis • Capacity to reproduce • Capacity to utilize energy • Two sides of the same coin: diversity and similarity of living systems • Evolution as the cornerstone of biology and living systems (explains diversity and similarity)

6. Themes/Characteristics • Hierarchy theory and emergent properties • Structure and function: “it is your cells, stupid” • Continuity of life based on information: “it is your genes, stupid” • Openness of biological systems • Regulatory capacity of living systems • Capacity to reproduce • Capacity to utilize energy • Diversity and similarity of living systems • Evolution of living systems

7. Hierarchical Nature of Living Systems Community Population Organism Organ Tissue Cell Organelles Macromolecules Atoms

8. Emergent Properties of Living Systems • Consequence of hierarchy theory: emergent properties • With each step up in the hierarchy, novel properties emerge that were not present at lower levels and were not predictable • Example: cell composed of trillions of macromolecules arranged in very precise ways that result in highly ordered and complex machinery (sum far greater than the parts)

9. Infrastructure of A Cell

10. Themes/Characteristics • Hierarchy theory and emergent properties • Structure and function: “it is cells, stupid” • Continuity of life based on information: “it is your genes, stupid” • Structure correlated with function • Openness of biological systems • Regulatory capacity of living systems • Capacity to reproduce • Capacity to utilize energy • Diversity and similarity of living systems • Evolution of living systems

11. Cell: Structure and Function • Organism’s basic unit of structure and function • Lowest level of structure capable of performing life’s activities • Most common basic structure of all living organisms • Robert Hooke (1665) and Anton van Leewenhook • Cell Theory • Ubiquitous nature of cells • All cells come from previous cells

12. Hooke’s Cell (Cork)

13. General Cell Structures

14. Themes/Characteristics • Hierarchy theory and emergent properties • Structure and function: “it is cells, stupid” • Continuity of life based on information: “it is your genes, stupid” • Openness of biological systems • Regulatory capacity of living systems • Capacity to reproduce • Capacity to utilize energy • Diversity and similarity of living systems • Evolution of living systems

15. Continuity of Life and Information • Order in any system originates from information and instructions that serve as a template for organizing “parts” • In living systems, instructions are encoded/inherited in the DNA • Inheritance is based on the precise order of nucleotides (ATCG) • Example: RAT versus TAR versus ART • Continuity of life is based on information that is: • Transferred from generation to generation over time • Preserved/stores at the molecular level in DNA

16. Infrastructure of A Cell

17. Themes/Characteristics • Hierarchy theory and emergent properties • Structure and function: “it is cells, stupid” • Continuity of life based on information: “it is your genes, stupid” • Openness of biological systems • Regulatory capacity of living systems • Capacity to reproduce • Diversity and similarity of living systems • Evolution of living systems

18. Themes/Characteristics • Hierarchy theory and emergent properties • Structure and function: “it is cells, stupid” • Continuity of life based on information: “it is your genes, stupid” • Openness of biological systems • Regulatory capacity of living systems • Capacity to reproduce • Diversity and similarity of living systems • Evolution of living systems

19. Open Systems • All living organisms are open systems, allowing organisms to interact with their environment • Processing stimuli from the environment • Responding to stimuli in the environment • Characterize an “open” versus a “closed” system • Examples • Orientation of leaves to sun • Eyes • Ears • Microbes and single cell organisms (e.g., amoeba)

20. The structure of the eye Figure 26.41 26-580

21. Themes/Characteristics • Hierarchy theory and emergent properties • Structure and function: “it is cells, stupid” • Continuity of life based on information: “it is your genes, stupid” • Openness of biological systems • Regulatory capacity of living systems • Capacity to reproduce • Capacity to utilize energy • Diversity and similarity of living systems • Evolution of living systems

22. Regulatory Systems • Constant interplay of organisms with the environment requires a well balanced regulatory system • Consequence is homeostasis • Set point, effectors, control centers and sensors • Analogy to thermostat for heat control • Examples • Enzymes in cells (lab exercise next week) • Thermostatic control of body temperature

23. Positive Feedback Control Center/ Sensor Set Point Effector Negative Feedback Regulatory Systems: Cybernetics • Feedbacks (+ and -), homeostasis and cybernetics

24. Themes/Characteristics • Hierarchy theory and emergent properties • Structure and function: “it is cells, stupid” • Continuity of life based on information: “it is your genes, stupid” • Openness of biological systems • Regulatory capacity of living systems • Capacity to reproduce • Capacity to utilize energy • Diversity and similarity of living systems • Evolution of living systems

25. Universality of Reproduction • Reproduction: regenerative process of making new organisms from previously existing organisms (not necessarily copies) • Methods • Sexual • Asexual (microbes; cell division/mitosis) • Ancillary but important function: creating new variants • Example: siblings

26. Themes/Characteristics • Hierarchy theory and emergent properties • Structure and function: “it is cells, stupid” • Continuity of life based on information: “it is your genes, stupid” • Openness of biological systems • Regulatory capacity of living systems • Capacity to reproduce • Capacity to utilize energy • Diversity and similarity of living systems • Evolution of living systems

27. Energy Utilization • Why is energy use an important theme? • Energy transduction • Thermodynamics (1st and 2nd laws) • Energy source is ________ • Energy capture • Autotrophs (energy from sun “directly” via phoptosynthesis) • Heterotrophs (energy from other organisms) • Energy storage • Chemical bonds (C-C bonds, which are _____ bonds) • ATP (adenosine triphosphate and ADP (adenosine diphosphate) • Energy dissipation • 2nd Law of Thermodynamicvs

28. Energy Flow ADP Catabolism Biosynthesis ATP

29. Themes/Characteristics • Hierarchy theory and emergent properties • Structure and function: “it is cells, stupid” • Continuity of life based on information: “it is your genes, stupid” • Openness of biological systems • Regulatory capacity of living systems • Capacity to reproduce • Capacity to utilize energy • Diversity and similarity of living systems • Evolution of living systems

30. Two Sides of a Coin: Diversity and Similarity • Diversity is a hallmark of living systems • 1.5 M known species of plants, animals and microbes • 100 M+ thought to exist • Similarity is a hallmark of living systems • Striking similarity at the molecular level (DNA) so you are more akin to worms, squirrels, birds and pigs (~90%!) than you think • Examples • Biochemistry • Structure and morphology • DNA • Conclusion: two sides of the same coin

31. Themes/Characteristics • Hierarchy theory and emergent properties • Structure and function: “it is cells, stupid” • Continuity of life based on information: “it is your genes, stupid” • Openness of biological systems • Regulatory capacity of living systems • Capacity to reproduce • Capacity to utilize energy • Diversity and similarity of living systems • Evolution and adaptation of living systems

32. Evolution and Adaptation • Define “evolution” • Define “adaptation” • Why is “evolution” and “adaptation” important in living systems • Examples of evolution • Macroscale: origin of species • Microscale: • Microbes resistant to antibiotics • Moths resistant to air pollution • Examples of adaptation • Articulation of the joints in animals • Planar structure of leaves

33. Evolution and Adaptation • Cornerstone theory of biology (relate to hypothesis) • Explains diversity of life • Explains similarity of life • Theories in biology are difficult to have stood the test of time and even more difficult to address very divergent features of living systems • Evolution is one of the long-standing theories that has the fascinating and unusual feature of explaining not only the diversity of life but at the same time the striking similarity among all living organisms • Charles Darwin (1859): Origin of Species

34. Take-Home Messages - Themes • Hierarchical nature of the living world • Emergent properties of living systems • Cell as a basic unit of structure and function • Continuity of life based on information • Openness of biological systems • Regulatory capacity of living systems: homeostasis • Capacity to reproduce • Capacity to utilize energy • Two sides of the same coin: diversity and similarity of living systems • Evolution as the cornerstone of biology (explains diversity and similarity)