Hi. In this video, we'll be talking about 2 very important aspects of animal physiology. Those are metabolism and homeostasis. Now before we get there, we need to understand some of the constraining factors on the animal form. Now, body size and functions are always going to be constrained by physics. For example, larger animals will weigh more and therefore, require thicker skeletons to support that weight, and also bigger muscles to move that weight around. Now one of my favorite examples of how physics can constrain the body size of animals has to do with terrifying giant insects. Believe it or not, millions of years ago there used to be some really scary big bugs out there. And fortunately for us, there are not today. Insects, in fact, basically have a much smaller maximum size than they did way back in prehistoric times when there were, you know, terrifyingly large insects. The reason for this, it's believed, has to do with the amount of oxygen in the atmosphere. There's a limit to how much oxygen can diffuse into an organism. We'll get into the details of all that when we talk about respiration, but, you know, just know that there's a physical limit on the availability of those gases to diffuse into tissues. Now back in these prehistoric times, there was a lot more oxygen in the atmosphere, which allowed for organisms like insects to grow larger than they can today. Because there's less oxygen in the atmosphere today, there's a smaller upper limit on bug size. So, never going to have to worry about that scenario, fortunately. Now, what this kind of gets into is this very important idea of surface area to volume ratio, which essentially, determines the physiology of an animal and its cells. Now, the reason for this is as organisms get bigger, this ratio of surface area to volume actually decreases. And we can see a nice example of that in this graph here that looks at area on the y axis and volume on the x axis. Now, as you can see, as our shapes get larger, if, you know, you look at the line from one shape, so to simulate a cell let's just look at the ball for argument's sake. So as this ball gets bigger you can see that as it gets bigger the line of its area versus volume curves. And it actually increases in volume at a faster rate than its area. So what does this mean? This means that as animals get bigger, they get, or they have less surface area compared to their volume. And this comes into play with ideas like molecular diffusion. Right? The more surface area you have, the more efficient your diffusion will be. It also relates to nutrient use and heat loss. It, organisms that are smaller basically use relatively more energy compared to organisms that are larger. We'll look at that in just a moment. Another way to think of this is that smaller organisms will actually lose more heat to the environment, relative to their larger counterpa
Table of contents
- 1. Introduction to Biology2h 40m
- 2. Chemistry3h 40m
- 3. Water1h 26m
- 4. Biomolecules2h 23m
- 5. Cell Components2h 26m
- 6. The Membrane2h 31m
- 7. Energy and Metabolism2h 0m
- 8. Respiration2h 40m
- 9. Photosynthesis2h 49m
- 10. Cell Signaling59m
- 11. Cell Division2h 47m
- 12. Meiosis2h 0m
- 13. Mendelian Genetics4h 41m
- Introduction to Mendel's Experiments7m
- Genotype vs. Phenotype17m
- Punnett Squares13m
- Mendel's Experiments26m
- Mendel's Laws18m
- Monohybrid Crosses16m
- Test Crosses14m
- Dihybrid Crosses20m
- Punnett Square Probability26m
- Incomplete Dominance vs. Codominance20m
- Epistasis7m
- Non-Mendelian Genetics12m
- Pedigrees6m
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- Introduction to Regulation of Gene Expression13m
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- Glucose's Impact on Lac Operon25m
- The Trp Operon20m
- Review of the Lac Operon & Trp Operon11m
- Introduction to Eukaryotic Gene Regulation9m
- Eukaryotic Chromatin Modifications16m
- Eukaryotic Transcriptional Control22m
- Eukaryotic Post-Transcriptional Regulation28m
- Eukaryotic Post-Translational Regulation13m
- 17. Viruses37m
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- 19. Genomics17m
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- 22. Evolution of Populations3h 52m
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- 27. Protists1h 12m
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- 30. Overview of Animals34m
- 31. Invertebrates1h 2m
- 32. Vertebrates50m
- 33. Plant Anatomy1h 3m
- 34. Vascular Plant Transport2m
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- 36. Plant Reproduction47m
- 37. Plant Sensation and Response1h 9m
- 38. Animal Form and Function1h 19m
- 39. Digestive System10m
- 40. Circulatory System1h 57m
- 41. Immune System1h 12m
- 42. Osmoregulation and Excretion50m
- 43. Endocrine System4m
- 44. Animal Reproduction2m
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- 48. Ecology3h 11m
- Introduction to Ecology20m
- Biogeography14m
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- Introduction to Terrestrial Biomes10m
- Terrestrial Biomes: Near Equator13m
- Terrestrial Biomes: Temperate Regions10m
- Terrestrial Biomes: Northern Regions15m
- Introduction to Aquatic Biomes27m
- Freshwater Aquatic Biomes14m
- Marine Aquatic Biomes13m
- 49. Animal Behavior28m
- 50. Population Ecology3h 41m
- Introduction to Population Ecology28m
- Population Sampling Methods23m
- Life History12m
- Population Demography17m
- Factors Limiting Population Growth14m
- Introduction to Population Growth Models22m
- Linear Population Growth6m
- Exponential Population Growth29m
- Logistic Population Growth32m
- r/K Selection10m
- The Human Population22m
- 51. Community Ecology2h 46m
- Introduction to Community Ecology2m
- Introduction to Community Interactions9m
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- Community Structure35m
- Community Dynamics26m
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- 52. Ecosystems2h 36m
- 53. Conservation Biology24m
38. Animal Form and Function
Metabolism and Homeostasis
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