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Summary
Environment Class 01

A BRIEF DESCRIPTION OF THE SUBJECT (5:04 PM)

  • Topics that would be covered
  • Basic concepts
  • Ecosystems
  • Biomes
  • Biodiversity
  • Water-related ecological concepts
  • Air/Atmosphere and climate change
  • Land degradation

BASIC CONCEPTS (5:39 PM)

  • The concept of ecology was given by Haeckel in 1869
  • Ecology is an applied science that studies the relationship between the living and non-living components
  • Carlyle explains environment as everything that surrounds a life form throughout its life.
  • It includes both living and non-living materials
  • Autoecology investigates the relationship of one species with its habitat
  • Syn-ecology is the study of the interaction of a group of species with their habitat
  • The biotic potential is the capacity or potential of a species to maximize its rate of multiplication or population growth
  • Ecotype: The variation in characteristics of the members of the population is because of variation in the genetic makeup
  • When genetic factors are responsible for differences in characteristics of the members of the population it is called genotype determinant
  • Ecad is the variation in characteristics in the members of a given population who have the same genetic makeup and therefore the variations are introduced by environmental factors
  • This reflects phenotypes
  • Species Plasticity: The capacity of a species to adjust to a different environment, structurally without making a special effort
  • It is mostly determined biologically
  • Adaptation is the capacity of the life form to exist under the given condition of its habitat.
  • This is because the condition in the same habitat can change periodically like winters becoming very severe for a part of the year, or summers becoming very severe in another habitat
  • Tolerance factors: They are the limiting factors of the habitat, which allow a given life form to exist and survive in a given habitat
  • Life forms will come under stress if the tolerance factors both upper and lower are exceeded
  • The choice for the life form, when tolerance factors are exceeded is to develop adaptations, migrate in search of other habitats, and if these are not possible the life form may perish
  • Habitat referred to the physical settings of the environment of a life form
  • The range is a greater term than habitat which may comprise different environments
  • The bioclimatic frontier is the geographic boundary marking the boundary of the range of a species
  • These boundaries are usually determined by climatic factors which act as tolerance factors

TAXONOMICAL CLASSIFICATION (7:00 PM)

  • Scientifically classification of life forms is taxonomy
  • Taxonomical classification starts with the concept of Domain which is the point of origin of life
  • There are three domains:
  • 1. Archae
  • 2. Bacteria
  • 3. Eukarya
  • Whittaker classified Kingdoms into the following types:
  • 1. Plante
  • 2. Animalia-  It is the largest Kingdom
  • 3. Fungi
  • 4. Protista
  • 5. Monera
  • The Plante Kingdom is further divided into divisions
  • Animal Kingdom is divided into Phylum
  • Phylum: All life forms built on the same plan where they have a common ancestral stock
  • The life forms in a given phylum can have a morphological similarity or developmental similarity or evolutionary similarity
  • Phylum is divided into classes
  • Class is a grouping where life forms have some common characteristics which are more than that in a phylum
  • For example, animals having a backbone belong to the phylum Chordata, and all those Chordata having milk-producing organs are part of Mammalia Class
  • Reptilia Class  is that group of Chordata that have scaly surface and does not feed their young
  • An Order has more common characters as compared to the Class and the similarities between members are more
  • Mammals that are flesh-eating belong to the carnivore Order
  • Order is further classified into Family
  • Similarities are much more visible in external characteristics or morphology forms Family e.g. Felidae or cat family
  • Family is divided into Genus
  • Grouping of species that are structurally related is Genus
  • The members of a genus cannot interbreed
  • Species is the last unit of taxonomy
  • Three things define species:
  • 1. A common gene pool
  • 2. Inbreeding or inter-breeding is a must
  • 3. Children grow up to look like parents when they become adults, i.e they have very high morphological similarities

ECOSYSTEM (7:40 PM)

  • The Biosphere is not a separate layer but a functional reality, a spatial unit on Earth that derives its components from Lithosphere, Hydrosphere, and Atmosphere
  • It is the functional space that includes all life form
  • Ecosystems are spatial units that unify living and non-living elements, by creating inter-relationships and inter-dependency
  • In other words, ecosystems bring together the living and the non-living elements of the earth into an interacting relationship
  • Biodiversity is focused more on a variety of living organisms along with their habitat
  • Three components of an ecosystem are energy (solar), biotic (living) components, and abiotic (non-living) components
  • Biotic parts have a tropic structure which is the categorization of life forms on the basis of the same number of steps through which they obtain their foods
  • R.C. Lindeman gave the concept of tropic structure
  • The maximum number of tropic levels an ecosystem can have is four
  • Tropic levels are producers (self-feeding or producing their own food), primary consumers (herbivores), secondary consumers (carnivores), and tertiary consumers (omnivores)
  • Autotrophs produce their food using the process of photosynthesis e.g. green plants
  • Chemotrops produce their food using chemicals e.g. bacteria
  • Heterotrophs feed on other life forms
  • Decomposers digest food outside their cells and absorb pre-digested materials
  • Saprophytes are also decomposers, but they secrete liquids of the dead plant and animal tissues and obtain food from this liquid

Topics for the next class: Food chains and food webs, positive and negative interaction between life forms, important species like keystone, endemic, energy pathways, the productivity of an ecosystem, and abiotic components