The Biosphere - All Experiences

Ecology on a Living Planet

Our Living Planet: Stability and Change

biosphere: part of Earth in which all of life exists including land, water, and air/atmosphere

• organisms:

  • interact w each other and physical components

  • respond to and change their environments

The Science of Ecology

ecology: scientific study of interactions among organisms and between organisms and their environment

Ecology and Economics

linked bc humans are a part of the biosphere → depend on ecological processes to provide essential water and food, which can also be bought and sold

Levels of Organization

(most specific → most broad)

1. species: a group of organisms that can breed and produce fertile offspring

2. population: a group of individuals of the same species that live in the same area

3. community: assemblage of different populations that live together in a defined area

4. ecosystem: all the organisms that live in a place, together with their nonliving environment

5. biome: a group of ecosystems that share similar climates and typical organisms

Biotic and Abiotic Factors

an organism’s environment consists of the abiotic and biotic factors that affect it

Abiotic Factors

abiotic factors: physical or nonliving factors that shape an ecosystem

• sunlight

• heat

• precipitation

• humidity

• wind / water currents

• soil type

stable factors = stable environments, some change thru seasons

plantetarily → wind, ocean currents, and water overall determine the stability of ecosystems

Biotic Factors

biotic factor: any living part of the environment with which an organism might interact

• important factors include predators, prey, competitors

planetary → predator and prey populations + human populations drive stability

Biotic and Abiotic Factors Together

ex: “muck” in shores of sand and pond has nonliving sand and mud particles, but it also has decaying organic material serving as food for bacteria → if it was ever living or containing living stuff, it’s biotic

abiotic conditions are shaped by organisms too → trees affect the sunlight and temp the “muck” experiences. trees also provide wind protection → impacts humidity. plant roots determine soil erosion. the type of decomposing oak leaves changes acidity of soil.

Global Systems

system: a network of relationships among parts, elements, or components that interact with and influence one another through the exchange of energy, matter, or information

the earth is divided into four spheres

1. biosphere

2. atmosphere: a thin layer of gases that surround earth

3. hydrosphere: all of the water (salt/fresh, liquid/ice/vapor) above and below Earth’s surface and in the atmosphere

4. geosphere: all of the rock at and below Earth’s surface

these parts often interact with each other

algae (biosphere) photosynthesize in the ocean (hydrosphere) and release oxygen into the air (atmosphere) for humans and animals to breathe, in which they live on the (geosphere)

Climate and Weather

changes in weather and climate determine the success/failure of crops and the stability of populations and communities

weather: day-to-day conditions of the atmosphere, including the temperature, precipitation, and other factors

climate: average year-to-year conditions of temperature and precipitation in an area over a long period of time

these determine the type of organisms that grow in ecosystems

climate is influenced by solar energy, latitude, and wind and ocean currents

Latitude and Solar Energy

solar radiation hits Earth at diff angles and at diff times bc Earth is curved and tilted on its axis, causing seasons

equator → sun directly overhead (not spreading out)→ little changes in daylight

poles → sunlight spreads out as winter sun drops lower → shortest winter days

EQUATOR has most solar energy

climate zones are produced by uneven distribution of heat/sunlight, tilted axis = seasons

polar zones: between 66.5 and 90 degrees north and south latitude; very cold winters, barely warm summers

temperate zones: between 23.5 and 66.5 degrees north and south latitude; hot summers, cold winters

tropical zones: 2; between 23.5 north and 23.5 south latitudes near the equator; warm/hot throughout year

Solar Energy and the Greenhouse Effect

Earth’s avg temp is determined by amount of heat trapped in biosphere and the amount lost to space

• controlled by concentration of three gases - carbon dioxide, methane, and water vapor → greenhouse gases trap heat

• greenhouse effect: the process in which certain gases (carbon dioxide, methane, and water vapor) trap sunlight energy in Earth’s atmosphere as heat

• part of their nutrient cycles → impacted by natural and human-caused changes

  • concentrations increase → earth heats, concentrations decrease → earth cools

Heat Transport in the Biosphere

unequal distribution of heat = global wind and ocean currents

warm rises, cool sinks

→ Global Winds

→ Ocean Currents