Unit 11 biodiversity and classification


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  • The Archaea are a group of single-celled microorganisms. Eukarya: The domain comprised of eukaryotes or organisms whose cells contain a true nucleus
  • Unit 11 biodiversity and classification

    1. 1. UNIT 11
    2. 2.  Biodiversity refers to the total number ofspecies found in an area. Includes the large variety of species, differentecosystems and genetic differences. Endangered species: species in danger ofextinction Threatened species: species likely to becomeendangered in the near future
    4. 4.  Ecologists describe biodiversity as anattribute of three other levels of biologicalorganization:◦ Genetic diversity: variation among members of apopulation, higher genetic diversity – higher chanceof survival.◦ Community diversity: community composition,increases the levels of biodiversity.◦ Landscape diversity: a group of interactingecosystems within one landscape.
    5. 5.  Biodiversity notevenly spreadthroughoutbiosphere◦ Protecting some areaswill save more speciesthan protecting otherareas Regions of the worldare calledbiodiversity hotspots◦ Contain unusually largeconcentrations ofspeciesCAPE REGION
    6. 6.  INDIGENOUSSPECIES Occurs in a placenaturally Native A species can beindigenous to anumber of places atonce ENDEMIC SPECIES Occurs naturallyonly in that place. Native to anexclusive or limitedarea. Not widelydistributed – wontbe found naturallyanywhere else.e.g. Madagascar Flying Foxendemic to Madagascar
    7. 7.  More than a million species of livingorganisms discovered and described◦ Estimated ±30 million species still to be discovered Scientists involved in describing species arecalled taxonomists
    8. 8.  Plant & animal species identified exhibit greatdeal of variation◦ In form, structure, mode of life & other aspects Plants & animals need to be divided intodiscrete groups based on the differences◦ In order to study them.
    9. 9.  Classification: the scientific practice ofidentifying, naming and grouping of livingorganisms. Branches of biology that deal withclassification:◦ Taxonomy deals with describing and namingorganisms.◦ Systematics deals with grouping and arranging thedescribed taxa into a hierarchical classification.
    10. 10.  Makes studying living organisms convenient. Helps in specific identification of an organism. Study of a few representatives from each distinctgroup helps to integrate idea of life as a whole. Reveals relationships among various groups oforganisms. Provides information about plants and animalsoccurring in specific geographical regions. Indicates evolutionary relationship◦ Establishing gradually increasing complexity of form andstructure in different groups of organisms.
    11. 11.  ARISTOTLE (Greek philosopher)◦ 1st to classify organisms◦ Either as plants or animals◦ He formulated the 2 kingdom system = Plantaeand Animalia◦ Plant group subdivided into 3 smaller groups:shrubs, herbs, and trees.◦ Animals subdivided into groups according towhere they lived: on land, water or in the air.
    12. 12.  Ernest Heackel Proposed adding a third kingdom = Protista Robert Whittaker (1969) Expanded the classification system to fivekingdoms Organisms were placed in these kingdoms basedon type of cell, complexity, and type of nutrition All prokaryotes were placed in the monerakingdom.◦ Organisms without a membrane bound nucleus
    13. 13.  Carl Woese (1970) Proposed 2 groups of prokaryotes afterresearching the rRNA◦ Bacteria◦ Archaea These also fundamentally different from eachother Should be assigned to separate domains◦ (higher classification category than a kingdom). Thus formulated a 3 domain system =Bacteria, Archaea and Eukarya
    14. 14. Linnaeus’s System Carolus Linnaeus (Swedish Botanist)developed a method of classifying organismsproperly. Based on classifying according to physical &structural similarities.◦ E.g. he might use the similarities in flower parts asa basis for classifying flowering plants. Became foundational way for today’s modernclassification systems.
    15. 15.  Modern classification systems use a two-wordnaming system called Binomial Nomenclature◦ Bi: two◦ Nomial: associated with a name Species is given a unique and stable name Meant that each species is composed of twoLatinised words (similar to name & surname)1. Genus2. species
    16. 16.  First word identifies the genus name of theorganism. A genus (plural form = genera) consists of agroup of similar species. Second word, the species, often describes acharacteristic of the organism. Scientific name = the Genus name + speciesname
    17. 17.  Example: Homo sapiens (wise man) Note: Genus name begins with capital letter Species name begins with lower case letter. Both names are always italicized orunderlined Example: Sutherlandia frutescens orSutherlandia frutescens
    18. 18.  Latin is the language of scientific names Many organisms have common names justlike you might have nicknames. Example:◦ Sutherlandia frutescens (scientific)◦ Cancer bush / Kankerbos (common) Accepted by speakers of all languages Each name applies only to one species Each species has only one name
    19. 19.  A Kingdom is the largest group in theclassification system Encompasses all the related species Living organisms are subdivided into 5 majorkingdoms:◦ MONERA◦ PROTISTA◦ FUNGI◦ PLANTAE◦ ANIMALIA◦ (Organisms cannot belong to more than one)
    20. 20.  Kingdom Monera Consists of all bacteria – simple, single celledorganisms with no nucleus
    21. 21.  Kingdom Protista Consists of single celled or simple multi-cellular organisms Some obtain energy by photosynthesis –algae. Some ingest other organisms Some absorb molecules through the cellmembrane E.g. Amoeba, Euglena.
    22. 22.  Kingdom Fungi: Single celled –e.g. yeast- to multi cellularorganisms Body composed of very fine threads –saprophytic nutrition
    23. 23.  Kingdom Plantae: Plants Multi cellular terrestrial organisms Cells have cell walls, obtain energy throughphotosynthesis Kingdom Animalia: Animals Multi cellular, aquatic and terrestrial organisms Cells have no cell wall, feed on other organisms