Ecology

• Branch of biology that deals with the relations between organisms and their surroundings.

• Biological Populations and Communities

  • Organisms that look similar in genetic makeup, chemistry and behavior belong to the same species.

  • Organisms of the same species that occupy a specific area are a population.

  • Populations of different species makes a community

  • An ecosystem is formed by the interaction of a community of organisms with their physical environment.

  • These make up the biosphere.

• Population Dispersal Patterns

  • Populations can be dispersed in 3 ways

  • Clumped

    • Dense with organisms in some communities.

    • When resources become scarce, organisms clump together to get those resources.

  • Random

    • Little interaction between organisms.

    • Usually in places consistent with environmental conditions and resources.

  • Uniform

    • Uniform spacing between individuals.

    • Usually arises from competition between resources.

• Ecological Niches

  • Area within a habitat occupied by an organism and includes the function of that organism within an ecological community.

Law of Tolerance

• States that the existence, abundance, and distribution of species depends on the tolerance level of each species to both chemical and physical factors.

• Limiting Factors

  • Abiotic factor that limits or prevents the growth of a population.

• Resource Partitioning

  • Resources in an environment are limited.

  • Some species have evolved to share a certain resource.

  • Spatial Partitioning - where the competing species use the same resource by occupying different areas within the range of the resource.

  • Morphological Partitioning - Where they share the species, but have evolved different structures to use the resources differently.

• Interactions between species

  • Amensalism - One species suffers, while the other species is not affected.

  • Commensalism - One species benefits, while the other species is not affected.

  • Competition - Prominent in predator-prey relationships.

  • Mutualism - Two species benefit

  • Parasitism - One species benefits, the other is harmed.

  • Predation - Predators hunt and kill prey.

  • Saprotrophism - Obtain nutrients from dead or decaying plants.

• Keystone Species

  • A species that contributes to a diversity of life and whose extinction would lead to an extinction of multiple species.

• Edge Effects

  • How a local environment changes along some type of boundary or edge.

Energy Flow

• The ultimate source of energy is the sun. Plants use the sun to produce food.

• Photosynthesis

  • Plants remove carbon dioxide from the atmosphere using photosynthesis.

  • Plants capture light through chlorophyll.

  • Oxygen is released into the atmosphere during photosynthesis.

• Cellular respiration

  • Organisms that rely on autotrophs are called heterotrophs.

  • Cellular respiration is the opposite of photosynthesis.

  • Glucose in the cells will result in carbon dioxide, water, and chemical energy to be produced.

• Ecological Pyramids and 10% rule

  • During the transfer of energy from one trophic level to the other, only 10% of energy is transferred.

  • The rest of the energy is lost in the form of heat, metabolic processes, and so on.

• Ecosystem Productivity

  • Of all sunlight that reaches earth, 3% for land plants, and <1% are used for aquatic plants.

Biomes

• Biomes

  • Biotic Community characterized by the dominant forms of plant life and the climate.

  • Temperature and precipitation are determinants of biomes.