Ecology and the Biosphere
Climate and the Biosphere
Climate is influenced by four main non-living things: temperature, water, sunlight, and wind.
Macroclimate: climate patterns on a large scale, like across the world, a region, or a landscape.
Microclimate: climate patterns on a small scale, like within a specific community of organisms (for example, under a log).
Latitudinal Variation in Sunlight Intensity
The angle of the sun's light affects how strong it is. Sunlight is most direct at the equator, while higher latitudes get sunlight at more of a slant.
Global Air Circulation and Precipitation Patterns
Dry air that goes down sucks up moisture, making dry areas around 30° latitude.
Moist air that goes up releases moisture, causing a lot of rain near the equator.
Seasonality
The amount of light and temperature changes more throughout the year closer to the poles because of Earth's tilt.
Areas of wet and dry air move as the sun's angle changes.
Bodies of Water
Oceans and big lakes help keep the climate steady in nearby land areas.
Currents move cold water from the poles toward the equator and warm water away from the equator.
Mountains
Air that rises drops moisture on the side facing the wind, creating a dry area on the other side.
Sides of mountains that face south in the Northern Hemisphere get more sunlight.
The temperature goes down about 6°C for every 1,000 meter increase in height.
Microclimate Factors
Abiotic factors: non-living things like temperature, light, water, and nutrients.
Biotic factors: other living things in an area.
Global Climate Change
Changes in Earth's climate can really change the biosphere.
Species might have to live in smaller areas or die out if they can't move to new places because of climate change.
Terrestrial Biomes
Biomes: big areas with specific types of plant life (on land) or physical conditions (in water).
Climate diagrams show the average temperature and rainfall each year.
Biomes are affected by the yearly patterns of temperature and rainfall.
Ecotone: a mix of two different biomes.
General Features of Terrestrial Biomes
Named for the main physical/climate conditions and plant life.
Layers of plants (like the canopy and understory) create different homes for animals.
Disturbance and Terrestrial Biomes
Disturbance: events like storms or fires that change a community.
Specific Terrestrial Biomes
Tropical Forest: high temperature, lots of rain, layers of plants, and lots of competition for sunlight; many different kinds of animals. Rainfall can be steady (rain forests) or change with the seasons (dry forests).
Desert: very little rainfall that changes a lot; temperature changes a lot between seasons and days; plants and animals store water. Located at 30° N/S.
Savanna: rainfall changes with the seasons, warm temperature, mostly grasses and forbs. Adapted to fire.
Chaparral: rainy winters and dry summers, mostly shrubs and small trees, adapted to fire. Located in coastal areas at mid latitudes.
Temperate Grassland: rainfall changes with the seasons, cold winters and hot summers, mostly grasses and forbs. Mostly turned into farmland.
Northern Coniferous Forest (Taiga): largest land biome, cold winters and rainfall changes, mostly conifers, cone-shaped to prevent branches from breaking under snow.
Temperate Broadleaf Forest: rainfall in all seasons, cold winters and hot/humid summers, mostly deciduous trees. Heavily settled but growing back in some areas.
Tundra: little rainfall and cold winters, mostly herbaceous plants. Permafrost stops roots from growing deep.
Aquatic Biomes
Defined by physical conditions; less change with latitude compared to land biomes.
Zonation in Aquatic Biomes
Photic zone: enough light for photosynthesis.
Aphotic zone: not much light.
Pelagic zone: both photic and aphotic zones.
Abyssal zone: very deep in the aphotic zone (2,000–6,000 m).
Benthic zone: sediment at the bottom made of organic and inorganic stuff.
Detritus: dead organic stuff; a source of food.
Aquatic Biomes Characteristics
Communities change with depth, light, distance from shore, and location in pelagic/benthic zones.
Lakes
Oligotrophic lakes: few nutrients, lots of oxygen.
Eutrophic lakes: lots of nutrients, little oxygen.
Littoral zone: shallow, lots of light, close to shore.
Limnetic zone: deep, too deep for plants to root, phytoplankton grow here.
Wetlands
Covered by water some of the time; lots of organic production/decomposition, little dissolved oxygen.
Very productive; clean water and help prevent floods.
Streams and Rivers
Defined by their current. Headwaters are cold, clear, turbulent, and full of oxygen.
Downstream waters are warmer, murkier, and have good oxygen levels.
Estuaries
Transition between river and sea; saltiness changes with tides, full of nutrients, and very productive.
Intertidal Zones
Covered and uncovered by tides; organisms deal with changes in temperature/saltiness and strong forces.
Oceanic Pelagic Zone
Constantly mixed by currents from wind; high oxygen levels.
Turnover in temperate oceans brings nutrients; tropical oceans have fewer nutrients.
Covers 70% of Earth’s surface.
Coral Reefs
Made from calcium carbonate skeletons of corals; need lots of oxygen and a solid place to grow.
Reef changes from fringing to barrier to atoll.
Marine Benthic Zone
Seafloor below coastal/pelagic zones; organisms in abyssal zone are adapted to cold/high pressure.
Hydrothermal vents support prokaryotes that use chemicals for energy.
Factors Influencing Species Distribution
Both living and non-living things affect where species live.
Dispersal and Distribution
Dispersal: moving individuals/gametes away from crowded areas.
Species Transplants
Moving organisms to new locations; success shows they could live in more places than they do now.
Behavior and Habitat Selection
Where species live is limited by their behavior in choosing a habitat.
Biotic Factors
Predation, herbivory, competition, mutualism, and parasitism.
Abiotic Factors
Temperature, water, oxygen, salinity, sunlight, and soil.
Temperature: affects how living things function; cells can freeze below 0°C, proteins break down above 45°C.
Water and Oxygen: Water affects how much oxygen is available; can be low in deep oceans/lakes.
Salinity: Affects the balance of water through osmosis; organisms are limited to freshwater/saltwater.
Sunlight: Affects photosynthesis; shade increases competition; water absorption limits how deep