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Evolution and Energy Flow in Earth's Ecosystem

Explore the concept of evolution and its connection to natural selection, as well as how energy flows within the global ecosystem. Understand the impacts of solar energy input, climate, and biomes on plant and animal adaptations. Discover the role of local climate and micro-climates in shaping vegetation patterns. Gain insights into the interplay of feedbacks, climate, and biology in governing ecosystems.

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Evolution and Energy Flow in Earth's Ecosystem

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  1. Wrap-up Natural Selection + Evolution… then…Energy Flow in the Global Ecosystem,PART I ES 100: October 6th, 2006

  2. Does Natural Selection  Evolution?

  3. Defining ‘evolution’ Scientific Definitions: • All the changes that have transformed life on earth from its earliest beginnings to the diversity that characterizes it today –Neil Campbell • The origination of species of animals and plants … –O.E.D. Common Usage: • A process of continuous change from a lower, simpler, or worse to a higher, more complex, or better state –Merriam-Webster’s Dictionary From a scientific point of view, evolution is just how new species come about

  4. Theory of Evolution: Criticisms • Microevolution is generally accepted, but macroevolution is hotly debated • How does evolution add information to a genome to create progressively more complicated organisms? • How is evolution able to bring about drastic changes so quickly? • How could the first living cell arise spontaneously to get evolution started? Pakicetus Ambulocetus Basilosaurus Humpback

  5. Today: Energy Flow in Earth Ecosystem Solar energy input imbalance  Climate Global climate  Biomes Biomes  Plant/Animal Adaptations

  6. Solar Energy Budget Reflected by clouds and atmosphere 23 albedo 100 Reflected by surface 8 Absorbed by atmosphere and clouds 57 20 2 47 Absorbed in photosynthesis  chemical energy drives climate  Absorbed as heat

  7. Weather describes short term variability Difficult to predict Butterfly effect Lorenz Climate describes typical conditions for a region More predictable Global Climate: Hadley Cells Tilt + Orbit = Seasons Frontal Systems  Biomes Local Climate: mountains oceans and lakes latitude elevation Micro-Climates Weather vs. Climate

  8. Uneven Heating of Earth LATITUDE: More Heat Energy at Equator than at Poles • sun’s rays hit more directly • less atmosphere to penetrate

  9. Uneven Heating of Earth LATITUDE: More Heat Energy at Equator than at Poles • sun’s rays hit more directly • less atmosphere to penetrate

  10. Hadley Cells: Heat Moves Air

  11. What’s missing? Biome: A large geographical region where plants have similar physiological adaptations to the climate.

  12. Another Energy Imbalance: Orbit + Tilt = Seasons

  13. Hadley Cells + Frontal Systems +Seasons = Biomes

  14. What’s missing? Biome: A large geographical region where plants have similar physiological adaptations to the climate.

  15. Biomes can be classified by precipitation and temperature. Boundaries are fuzzy (ecotones) !

  16. Arctic Tundra: • Short, intense growing season • Intense cold • Strong winds • Permafrost • Low primary productivity • Slow decomposition • Lots of C held in soil

  17. Boreal Forest Why the cone-shaped trees? • Cold, long, snowy winters • Warm summer

  18. Temperate forest: • Evergreen and deciduous • Intermediate temperature • Adequate moisture • Few constraints on growth High primary productivity

  19. Temperate Grasslands: • Continental regions - hot summer, low rainfall • Fires • Windy

  20. Tropical Savanna Grassland • Similar to Temperate Grasslands • hot summer • moderate rainfall • Fires

  21. Deserts: • North and south of tropics • Dry • Hot or cold Natural selection: Convergent Evolution

  22. Plant adaptation to hot environments: Physical Structure

  23. Plant adaptations: Physiology • Stomata must be open to take in CO2 • Open stomata = water loss • How can a plant minimize water loss? • Keep stomata closed as much as possible • Open only at night = CAM plants • Cactus, some epiphytes, succulents • Open only a little bit = C4 plants • Some grasses

  24. Tropical rainforests: • Near the equator • Hot • Moist conditions • Fast Decomposition • High primary productivity • Tight cycling of nutrients- soils are actually quite poor

  25. Where is SantaBarbara?

  26. Chaparral or Mediterranean-type • Strong seasonality • Hot, dry summers • Mild, wet winters  high productivity • Fires feed on large fuel supply

  27. Most Rapidly Expanding Biome?

  28. Summary: Solar energy input imbalance  Climate Global climate  Biomes Biomes  Plant/Animal Adaptations NEXT: Local climate and micro-climates effect smaller scale vegetation patterns Ecosystems governed by: feedbacks, climate, biology

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