The Biosphere: An Introduction to Earth’s Diverse Environments Chapter 34 The Biosphere: An Introduction to Earth’s Diverse Environments

A Mysterious Giant of the Deep There are about 1,000 known species of squid But until recently, no one had reported on this “mystery squid”

Deep-sea submersibles Are allowing scientists to study uncharted depths of the ocean Figure A

At depths of up to 2,500 meters Scientists are observing new environments and a great variety of organisms Figure B Figure C

Ecology Is the scientific study of the interactions of organisms with their environments

34.1 Ecologists study how organisms interact with their environment at several levels At the organismal level Ecologists may examine how one kind of organism meets the challenges of its environment Figure 34.1

At the population level Ecologists might study factors that limit population size At the community level An ecologist might focus on interspecies interactions

Ecosystem interactions involve Living (biotic) communities and nonliving (abiotic) physical and chemical factors

34.2 The biosphere is the total of all of Earth’s ecosystems Is the global ecosystem Figure 34.2A

Patchiness of the environment Characterizes the biosphere Figure 34.2B

34.3 Environmental problems reveal the limits of the biosphere CONNECTION 34.3 Environmental problems reveal the limits of the biosphere Human activities, including the widespread use of chemicals Affect all parts of the biosphere

Rachel Carson, a famous ecologist Was one of the first people to perceive the global dangers of pesticide use Figure 34.3

34.4 Physical and chemical factors influence life in the biosphere Abiotic factors determining the biosphere’s structure and dynamics include Solar energy, water, temperature, wind, and disturbances Figure 34.4

34.5 Organisms are adapted to abiotic and biotic factors by natural selection Unique adaptations Allow the survival of organisms in particular habitats Figure 34.5

Biotic factors, such as predation and competition Can lead to the evolution of adaptations by natural selection

34.6 Regional climate influences the distribution of biological communities Most climatic variations Are due to the uneven heating of Earth’s surface as it orbits the sun Low angle of incoming sunlight Sunlight strikes most directly Low angle of incoming sunlight Atmosphere 60ºS South Pole Tropic of Capricorn 30ºS 0º (equator) 30ºN Tropic of Cancer North Pole 60ºN Figure 34.6A

The tilt of the Earth’s axis Causes the changes of the seasons in the northern and southern hemispheres March equinox (equator faces sun directly) June solstice (Northern Hemisphere tilts toward sun) Constant tilt of 23.5º December solstice (Northern Hemisphere tilts away from sun) September equinox Figure 34.6B

Ascending moist air releases moisture The uneven heating of the Earth Also sets up patterns of precipitation and prevailing winds Descending dry air absorbs moisture Trade winds Ascending moist air releases moisture Doldrums Temperate zone Tropics 30º 23.5º 0º 60ºN 30ºN 30ºS Figure 34.6C, D

Influence coastal climate Ocean currents Influence coastal climate Fresno 104º Paso Robles 93º Bakersfield 106º Death Valley 119º Pacific Ocean Santa Barbara 75º Los Angeles (Airport) 74º San Diego 75º 40 miles San Bernardino 101º Riverside 91º Palm Springs 104º Burbank 86º Santa Ana 84º Key 70s (ºF) 80s 90s 100s 110s Figure 34.6E

Landforms such as mountains Affect rainfall Pacific Ocean Coast Range Wind direction Sierra Nevada East Figure 34.6F

34.7 Oceans occupy most of Earth’s surface AQUATIC BIOMES 34.7 Oceans occupy most of Earth’s surface Several characteristics shape ocean communities Light, distance from shore, and the availability of nutrients

The intertidal zone, an oceanic zone Is the area of shore where the ocean meets the land Figure 34.7A

Oceanic zones also include The pelagic and benthic zones Intertidal zone Photic zone 200 m Continental shelf 2,500–6,000 m Benthic zone (seafloor) Pelagic zone Aphotic zone Figure 34.7B

Are found in warm waters above continental shelves Coral reefs Are found in warm waters above continental shelves Figure 34.7C

Are productive areas where rivers flow into the ocean Estuaries Are productive areas where rivers flow into the ocean Figure 34.7D

34.8 Freshwater biomes include lakes, ponds, rivers, streams, and wetlands Factors that shape lake and pond communities include Light, temperature, and the availability of nutrients and dissolved oxygen

Abiotic factors change from the source of a river to its mouth And communities vary accordingly Figure 34.8A

Wetlands include Marshes and swamps Figure 34.8B

34.9 Terrestrial biomes reflect regional variations in climate Temperature and rainfall Mainly determine the terrestrial biomes

Major terrestrial biomes 30ºN Tropic of Cancer Equator Tropic of Capricorn 30ºS Tropical forest Savanna Desert Chaparral Temperate grassland Temperate broadleaf forest Coniferous forest Tundra High mountains Polar ice Figure 34.9

34.10 Tropical forests cluster near the equator Tropical rain forests Are the most diverse ecosystem Figure 34.10

34.11 Savannas are grasslands with scattered trees Are dry and warm Figure 34.11

34.12 Deserts are defined by their dryness Are the driest biomes Figure 34.12

34.13 Spiny shrubs dominate the chaparral Is a shrubland with cool, rainy winters and dry, hot summers Figure 34.13

34.14 Temperate grasslands include the North American prairie Are found where winters are cold Figure 34.14

34.15 Broadleaf trees dominate temperate forests Temperate broadleaf forests grow throughout midlatitude regions Where there is sufficient moisture to support the growth of large trees Figure 34.15

34.16 Coniferous forests are often dominated by a few species of trees The northern coniferous forest, or taiga Is found where there are short summers, and long, snowy winters Figure 34.16

34.17 Long, bitter-cold winters characterize the tundra Arctic tundra Is a treeless biome characterized by extreme cold, wind, and permafrost Figure 34.17

Alpine tundra Occurs above the treeline on high mountains

34.18 Ecologist Ariel Lugo studies tropical forests in Puerto Rico TALKING ABOUT SCIENCE 34.18 Ecologist Ariel Lugo studies tropical forests in Puerto Rico The Luquillo Experimental Forest Allows ecologists to study the effects of disruption on tropical forests Figure 34.18A, B