environmental science

• Environmental science is a field of Science that deals with the study of interaction between human system and natural system
• Environmental science deals with the physical, biological and chemical sciences to study the environment and discover solutions to environmental problems
• Importance of Environmental Science


  • To understand the interrelationship between organisms
  • To understand the impacts of development on environment
  • To realize that environmental problems are global and to create awareness about environmental problems at local, national and international levels
  • To discover sustainable ways of living and to utilize natural resources efficiently
  • To enlighten people about contemporary concepts such as how to conserve biodiversity
• Ecology


  A branch of biology that deals with the interrelationship between living things and to its environment
• Oikos


  Greek word meaning house or environment
• Two main branches of ecology

  • Autecology - population ecology
  • Synecology - community ecology
• Levels of biological organization

  • Cell - smallest unit of living things
  • Tissue - group of cells
  • Organ - group of differentiated tissues doing the same work
  • Organ system - group of organs that perform different functions
  • Organism - individual living thing
  • Population - group of similar organisms occupying a definite area
  • Community - group of different populations interacting with one another
  • Ecosystem - group of communities interacting with their abiotic factors
  • Biosphere - all the ecosystem on earth with its physical environment
  • Earth - the planetary environment
• Components of ecosystem


  • Abiotic factor
  • Biotic factor
• Water


  An odourless, tasteless inorganic substance made of two hydrogen and an oxygen
• Importance of water


  • Helps in seed germination
  • Transports substances in the body of plants and animals
  • Comprises a large percent of the body of organism
  • Serves as habitat for marine and freshwater organisms
• Types of plants according to water requirement

  • Hydrophytes - Plants that need abundant supply of water
  • Halophytes - Plants that can survive with water containing high salinity
  • Mesophytes - Plants that need a moderate supply of water
  • Xerophytes - Plants that can tolerate scanty water supply
  • Tropophytes - Plants that live in an environment in which heavy rainfall alternates with periods of drought
• Soil


  Material formed from small particles of rock mixed with organic materials and minerals and found in the upper layer of the earth crust
• Types of soil


  • Sandy - soil that have the largest particle. Plants do not grow well because water goes rapidly through the spaces and water dries off quickly
  • Clay - smallest particle of soil. It retains water before drying so it is sticky, often damp, and not suitable for plant growth
  • Silt - soil that is smaller than sand but larger than clay. It can hold water better than sand and usually carried by moving current. It is found near the river and other water bodies
  • Loam - soil that is good for agriculture and made up of sand, silt and clay with organic material called humus
• Sunlight


  The main and the oldest of all energy sources. Sunlight is needed by plants for photosynthesis and animals for warmth
• Temperature


  The hotness or coldness of an area. The temperature may affect the presence or absence of animals in different habitat. Some animals may escape cold by hibernation or migration. Some live normally in hot spring at a temperature
• Biotic factors


  The living components of an ecosystem. There are biological relationships that happen in an ecosystem. It may be between individual of the same species (intraspecific) or between different species (interspecific)
• Interaction in an ecosystem

  • Abiotic-abiotic - interaction/relationship among physical factors
  • Biotic - biotic - interactions/relationship among biotic factors
  • Biotic- abiotic factor - relationship between living and non-living things
• Population


  A group of similar species living in a certain place at the same time. Population is the major unit of the ecological study for scientists
• Characteristics of population


  • Size - number of individuals in a population
  • Density - number of individuals of a species living in a particular area of that population
  • Distribution - the arrangement of the individuals of a population with a particular space
• Types of distribution


  • Random distribution - no specific order, the organism is spread throughout the area without an overall pattern
  • Uniform distribution - the organisms are evenly distributed over an area
  • Clumped distribution - the organism are concentrated in an area
• Biotic potential


  The number of offspring that could exists if all offspring survived and produced young. It depends on the number of offspring produced and how frequently they are produced and how long the life of organism may be
• Environmental resistance


  Factors that reduces the growth rate of a population. It results to an increase in mortality and decrease in natality. Some resistance are result of resource shortage, water or food. Some comes from disease, predation or competition
• Carrying capacity


  The number of individuals in a particular population that the environment can support over an indefinite period of time in terms of food, space and shelter
• Limiting factors


  • Density dependent limiting factor - Factors directly associated with living things. Biotic factors are dependent on the density of the population, the effect of competition, predators, diseases, availability of space and food
  • Density independent limiting factors - Factors that influence all population. The amount of available air, water and soil condition are abiotic factors that are not associated with living things
• Community


  Group of different populations interacting with one another
• Symbiosis


  Relationship between two or more organism in which one or both organism benefited
• Symbiotic relationships


  • Mutualism - relationship where both organisms benefited
  • Commensalism - relationship where one organism benefited while the other is unaffected or unharmed
  • Parasitism - relationship where one organism benefited while the other is harmed/affected
• Competition


  Relationship where two or more organisms living in the same area and uses same resources compete with one another for the resources needed
• Predation


  Relationship where one organism is the prey (organism that is eaten) and another organism is the predator(organism that eats another organism)
• Community roles


  • Food getting
  • Autotrophs - organism that can make their own food from inorganic matter and energy from the sun
  • Heterotrophs - organism that cannot make their own food and obtained their nutrients from another organism
  • Producers - organism that produces their own food
  • Consumers - consume another organism
  • Herbivores - organism that consume plants
  • Carnivores - organism that eat meat or another animal
  • Omnivores - organism that eat both plant and animals
  • Decomposers - organism that eat dead plants and animals
• Types of decomposers


  • Scavengers - eat soft tissues
  • Detritivores - consume dead organic matter and digest them internally
  • Saprotrophs - consume the left overs of the two other decomposers. They secrete an enzyme to digest dead matter and then absorb the nutrients in it
• Trophic levels


  • Primary producers - Autotroph that convert sun energy into chemical energy
  • Primary consumers - eat the primary producers
  • Secondary consumers - eat the primary consumers
  • Tertiary consumers - eat the secondary consumers
  • Decomposers - consumers that obtain their energy by consuming dead plants
• Food chain


  The sequence of events in an ecosystem, where one organism eats another and then is eaten by another organism. It follows a single path as animals eat each other
• Food web


  Shows how plants and animals are connected to help them all survive. Food chains follow just one path of energy as animals find food
• Ecological pyramids


  • Pyramid of numbers - shows the number of organism at each trophic level per unit area of ecosystem
  • Pyramid of biomass - shows the mass of organism at each stage of the food chain
  • Pyramid of productivity - shows the energy at each trophic level
• Ecological succession


  Sequence of replacement in a habitat
• Types of ecological succession

  • Primary succession - Taking place which is not previously covered by vegetation
  • Secondary succession - takes place in a habitat already previously occupied by vegetation
• Ecosystem


  A group of communities that interact with one other and with their physical environment. Ecosystem is composed of biotic and abiotic factors
• Biome


  A group of land and water ecosystems with similar climates and organisms
• Types of ecosystems


  • Terrestrial ecosystem
  • Aquatic ecosystem