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
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
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.
Biodiversity notevenly spreadthroughoutbiosphere◦ Protecting some areaswill save more speciesthan protecting otherareas Regions of the worldare calledbiodiversity hotspots◦ Contain unusually largeconcentrations ofspeciesCAPE REGION
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
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
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.
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.
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.
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.
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
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
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.
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
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
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
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
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)
Kingdom Monera Consists of all bacteria – simple, single celledorganisms with no nucleus
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.
Kingdom Fungi: Single celled –e.g. yeast- to multi cellularorganisms Body composed of very fine threads –saprophytic nutrition
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