Ch 51: Introduction to Ecology and The Biosphere

• Ecology

the study of interactions between living organisms and the environment

• Levels of ecology

• Organism

• Population

• Community

• Ecosystem

• Organism

an individual

• Population

individuals of the same species that live in the same area

• Community

living organisms of multiple species in the same area

• Ecosystem

all biotic (living) and abiotic (non-living) components of an area

• Climate

• Long term prevailing weather conditions in an area

• Key factors: temperature, precipitation, sunlight, wind

• Latitude affects sunlight

light from the sun hits the tropics directly, higher latitudes are hit at an oblique angle

• Global air circulation and precipitation

• Sunlight warms air at the equator

• Warm air rises, then cools and releases precipitation in tropical regions

• Dry air descends and absorbs moisture from latitudes near 30

• As earth rotates, it deflects air in predictable wind patterns

• Ocean currents

• Wind pushes the ocean surface causing surface currents

  • Currents bring warm water up the eastern coast of continents and cool water down the western coast of continents

• What attribute of water allows water temperature to regulate costal temperatures

high specific heat

• Seasonality

caused by earth’s tilted axis and rotation around the sun

• Variation in climate is highest in where and lowest in where

highest towards the poles, lowest in the tropics

• Upwelling

when warm water cools and sinks replaced by nutrient rich deep cold water

• How does mountains influence airflow over land

• Warm air rises and cools, releasing precipitation on the windward side of the mountain

• Dry air passes over and absorbs moisture on the leeward

• How does vegetation/forests affect surface temperature and precipitation

forest reduces Earth’s surface temperature and increase precipitation

• Distribution

(where species live) consequences of evolutionary history and ecological factors

• Dispersal

the movement of individuals or gametes away from their area of origin

• Biotic factors

other species can limit distribution of species

• Predators and herbivores

• Pollinators

• Food resources

• Parasites

• Pathogens

• Competition

• What are all the abiotic factors

• Temperature

• Water and oxygen

• Salinity

• Sunlight

• Rocks and soil

• Temperature

• Organisms function best within a specific range of temperatures

• Coral reefs grow in narrow temperature range

• Water and oxygen

• Water level changes in intertidal regions

• Desiccation (drying out) in terrestrial environments

• Water affects oxygen availability because it is slow to dissolve

• Salinity

• Salt concentration in the water (parts per thousand)

• Some organisms regulate their salt levels, other conform to the water around them

• Sunlight

• Plants compete for light in a forest canopy

• Sunlight is absorbed quickly in water

• Rocks and soil

• Soil pH, mineral composition and physical structures can limit distribution of plants and herbivores

• Global climate change

• The burning of fossil fuels and deforestation are increasing the concentration of CO2 in the atmosphere which affects warming of the planet (greenhouse effect)

• Climate change affects distribution of living species through temperature and precipitation changes

  • Shortage of suitable habitat, cannot migrate quickly enough

• Ecological change and evolution

ecological interactions can cause evolutionary change and vice versa

• Example: evolution of plants lead to changes in atmospheric CO2 and atmospheric O2 → plants lead to new habitats and food sources allowing for adaptive radiation