ECOSPHERE

Definition of Ecosphere

• domain of life on Earth
• the thin layer of Earth where life exists
• the intersection of the hydrosphere, lithosphere, and atmosphere where life exists
• ecosphere = biosphere


• The biosphere is the sum total of all places in which organisms live. It includes:
• hydrosphere
• lithosphere
• atmosphere

System for Classifying Life on Earth

• Kingdom (Monera, Protoctista, Fungi, Platae, Animalia)
• Phyla
• Classes
• Order
• Families
• Genera
• Species

Requirements For Life

• all forms of life (that we know of) require energy and liquid water


• the ultimate source of energy for all life (except some bacteria) is solar radiation


• Earth's unique position
• Mercury and Venus (closer to the sun) receive so much energy that their water has been vaporized


• The planets further from the sun than Earth receive such low levels of energy any water present is frozen and unable to sustain life


• The two planets closest to the Earth
• Venus: the surface temperature is high enough to melt lead due to runaway "Greenhouse Effect"


• Mars: surface temperature is

• Solar energy is converted to chemical energy by Earth's green plants through photosynthesis
• Photosynthesis is the process plants use to convert inorganic material into organic matter, using the assistance of light energy
• Light energy enables the smaller inorganic molecules (water and CO₂) into organic sugar molecules


• Process releases oxygen


• Sugar is used as a source of energy by plants and animals that eat the plants


• Respiration

Ecological Concepts

• Environment - everything that affects an organism in its lifetime
• Abiotic factors of the environment
• flow of energy


• physical factors
• climate
• temperature
• precipitation
• soil, etc..


• Biotic
• all forms of life that an organism interacts with


• Limiting Factors - a shortage or absence of a key factor that restricts the success of an organism
• Range of tolerance


• Habitat and Niche
• Habitat - the space that an organism inhabits
• soil type
• availability of water
• climate
• plant species, etc..


• Niche - the functional role that an organism has in its surroundings



• Natural Selection - process of more successful individuals surviving and reproducing larger number of offspring than those that are less successful
• Species - a population of organisms in which the individuals are potentially able to interbreed and produce fertile offspring



• Mechanisms of Natural Selection
• Charles Darwin (1859) "On the Origin of Species by Means of Natural Selection"
• Individuals within a species showed variation


• Organisms within a species typically produce many more offspring than can survive


• The excess number of individuals results in a struggle for survival


• Because of the variation among individuals, some have a greater chance of surviving and reproducing than others


• As time passes and each generation is subjected to the same process, the percentage of individuals showing favorable variations will increase and those having unfavorable variations will decrease

• Kinds of Organism Interactions
• Predation


• Competition
• intraspecific competition
• interspecific competition


• Symbiotic Relationships: a close, long-lasting, physical relationship between two species in which at least one species derives nourishment from the other
• Parasitism


• Commensalism


• Mutualism