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