The biosphere: an introduction to Earth’s diverse environments

1. The biosphere: an introduction to Earth’s diverse environments • The biosphere • Aquatic biomes • Terrestrial biomes

2. What do Ecologists Study? • Organismal level: • How physiology or behavior impacts a species

3. What do Ecologists Study? • Population level: • How members of the same species interact

4. What do Ecologists Study? • Community level: • How different populations interact

5. What do Ecologists Study? • Ecosystem level: • Interactions of living and non-living (abiotic) factors (temp, energy, water, chemicals, etc.)

6. The biosphere is the total of all of Earth’s ecosystems • Biosphere: global ecosystem • Includes atmosphere several km above earth, below ocean surface, etc. • Biosphere is patchy: • Deserts, forests, grasslands • Within a desert: • Saguaro cactus populations • Moist soil near saguaro • Top 1 cm of soil

8. Environmental problems reveal the limits of the biosphere • In the 1950s, it was thought that humans could manipulate the environment to their liking with little/no permanent damage • DDT had long-lasting effects

9. Physical and chemical factors influence lie in the biosphere • Solar energy: • Powers nearly all terrestrial and shallow-water systems • Water: • Essential to all life, water balance is constant challenge for organisms • Temperature: • Impacts metabolism (high or low can be bad) • Wind: • Impacts availability of other abiotic factors

11. Organisms are adapted to abiotic and biotic factors by natural selection • Species may evolve in a location, or may disperse there • They will only remain there is they are adapted to the environment • Is there suitable food? • Is the temperature adequate? • Is there adequate water? • What kinds of predators are there?

12. Regional climate influences the distribution of biological communities • Tropics: • From 23.5o north (Tropic of Cancer) to 23.5o south (Tropic of Capricorn) • Intense solar radiation • Temperature zone: • Between the tropics and the poles • Less intense solar radiation

15. Regional climate influences the distribution of biological communities • Winds • Doldrums: at the equator, light winds due to evaporation of water • Trade winds: movement of air in the tropics • Prevailing winds: result from combined effect of earth’s rotation and trade winds • Ocean currents • Riverlike flow of water in the oceans • Water moderates temperature extremes

20. Aquatic Biomes: Ocean • Covers about 75% of Earth’s surface • Intertidal zone: Exposed during low tide, pummeled during high tide, tide pools • Pelagic zone: open ocean • Benthic zone: sea floor • Photic zone: water and ocean bottom where light penetrates • Aphotic zone: no light penetration

23. Aquatic Biomes: Ocean Edge • Coral reefs: ecosystems revolving around corals and their spiny skeletal remains

24. Aquatic Biomes: Ocean Edge • Estuary: area where freshwater meets salt-water

25. Aquatic Biomes: Ocean Edge • Wetland: transition between aquatic and terrestrial ecosystems

26. Freshwater Biomes • Include lakes, ponds, rivers, streams, and wetlands • Photic zone supports phytoplankton, plants, benthic communities diverse • Temperature of water plays a large role in shaping the freshwater communities • Moving bodies of water (rivers, streams) have different communities than lakes • Wetlands: swamps, marshes, bogs

28. Terrestrial biomes reflect regional variations in climate • 8 major biomes • Each has characteristic types of vegetation, fungi, animals • Climate (temp and rainfall) is the major determiner of biome • Lots of variation within each biome • Human activity altering biomes at a fast pace

30. Terrestrial Biome: Tropical Forests • 11-12 hour days all year long • Nutrient poor soil • Clearing the tropical forests have increased in recent decades

31. Terrestrial Biome: Savannas • Rainfall: 30 – 50 cm per year; warm temps all year round • Frequent fires, herbivores prevent trees from establishing • Mostly grasses and forbs • Grazers, insects, burrowing animals, large predators

33. Terrestrial Biome: Deserts • Low (< 30 cm), unpredictable rainfall • Atacama (Chile) has <0.1 mm rain annually • Some are very hot, some are cold • Occur at 30o north/south, mtn rain shadow

34. Terrestrial Biome: Chaparral • Dense, spiny shrubs with evergreen lvs • Mild, rainy winters; hot, dry summers • Adapted to periodic fires • Browsers and seed eaters common

35. Terrestrial Biome: Temperate Grasslands • Similar to savannas, but mostly treeless • Persist due to drought, fire, and grazers • Amount of rainfall influences height of grass • Tall grass prairie: wetter areas (Kansas) • Short grass prairie: dry areas (SoDakota)

38. Terrestrial Biome: Temperate Forests • Mid-latitude regions with sufficient rainfall • Dominant species: oak, hickory, birch, beech, maple (deciduous trees) • Temps range: very cold in winter, very warm in summer • Precip comes all year • Rich soils- thick leaf litter

40. Terrestrial Biome: Coniferous Forests • Largest terrestrial biome on earth • Also at high altitudes in mid latitudes • Long cold winters; short wet summers • Lots of snow is common • Big animals: moose, elk, bears

41. Terrestrial Biome: Tundra • Northernmost limit of plant growth and high altitude • Dwarf shrubs, grasses, mosses, lichen • Winter: very cold, little light • Summer: mild, LOTS of light • Permafrost: continuously frozen sub-soil (surface soil defrosts, but not deep soil) • Very insulated animals, many migrate

43. Polar Ice • In Northern Hemisphere, ice covers land north of tundra • In Southern Hemisphere, ice covers Antarctica • Some mosses, lichen • Nematodes, mites, springtails in soil

45. Global Water Cycle • Water evaporated from ocean, lakes, and plants • Moved by wind patterns • Human activities altering global water cycle