Biodiversity and Classification Flashcards
The variety of life forms in a particular area
Biodiversity
Various levels of biodiversity
- Genetic diversity
- Species diversity
- Ecosystem diversity
Species diversity
The variety of species in a particular area
Genetic diversity
The genetic variety within a particular taxon
Ecosystem diversity
The variety of ecosystems in a particular area
Southern Africa
South Africa
Namibia
Botswana
Zimbabwe,
Mozambique,
Swaziland
and Lesotho
Reasons for high levels of biodiversity in Southern Africa
- Unique physical characteristics
- High Plateau
- Different oceans with warm Agulhas currant and cold Benguela current
- Unique Cape Floral Kingdom in the south west
Indigenous species
Species that occur naturally in a particular area e.g. country
Exotic/alien species
Species that do not occur naturally in a particular area, but have been introduced by humans by mistake of deliberatly
Endemic species
Species that occur only in one particular area and nowhere else in the world
Endangered species
Species threatened for various reasons and risk extinction
Extinction
When there are no longer any living members of a particular taxon, normally a species.
Biodiversity ‘hotspots’ in South Africa
The Cape Floral region
Succulent Karoo
Maputaland-Pondoland-Albany
The region in the cape that has one of the richest biodiversity of plants in the world
The Cape Floristic Region
The Cape Floristic Region
- South Western Cape region
- Area around 90 000 km2 (0.05% of earth surface)
- Contains 3% of all plant species
- 70% of the 9600 vascular plants are endemic
UNESCO
United Nations Educational, Scientific and Cultural Organisation
Why the Cape Floristic Region is a World Heritage Site
- Declared by UNESCO
- An area with one of the richest plant diversity
- Provides exceptional value to humanity worldwide
The Succulent Karoo
- West coast of South Africa
- Home to 5000 vascular plants
- 40% endemic and 18% endangered
Maputaland-Pondoland-Albany
- East coast of South Africa
- Home to 600 tree species
- Temperate forests with largest tree floral kingdom on earth
- Many threatened grasslands and forests
How biodiversity is organised by scientists
- Classification systems
- According to shared characteristics and common ancestry organisms are grouped
- Groups of organisms assigned as taxa
Taxa
- Groups into which organisms are classified based on shared characteristics.
- Singular: Taxon
Taxonomy
The science of naming, sorting and grouping organisms with shared features
Nomenclature
The science of naming taxa
Systematics
- Studying the evolutionary history of life on earth.
- Hypothesis automatically generated if two organisms are placed in the same taxon: the organisms are related to each other evolutionarily, they share a common ancestor
Why formal taxonomy?
(why group and name organisms?)
- Standardised globally
- Communicate and document biodiversity
- Easier to process vast numbers of species
- Important to ensure conservation
- Can ascribe common properties to taxa e.g. uses
- Better undestanding of how different groups evolved
Aristotle’s role in biological classification
- Two “kingdoms” recognised
- Plants and Animals
- These were further split into smaller groups
How did ancient scientists name taxa (nomenclature)
Names were short descriptions in Latin (i.e. long!)
The “father” of modern taxonomy
Carolus Linnaeus
Main contributions by Linnaeus to taxonomy
- Introduced binomial nomenclature
- Introduced ranked heirarchy (Kingdom, Class, Order, Family, Genus and Species)
Binomial nomenclature rules
- Name has two parts: Genus and Species
- Genus name written with a capital letter
- Species name written with a small letter
- Both written in italics or underlined (when handwritten)
What are the modern taxon heirarchies
- Kingdom,
- Phylum (animals) / Division (Plants),
- Class,
- Order,
- Family,
- Genus,
- Species
How are the different taxon heirarchies organised?
- The system starts with Kingdom
- Each consecutive level becomes more and more specific
- E.g. Organisms of the same Family have more in common than organisms of the same Order
Influence of Darwin on Taxonomy
- Taxa have more significance since Darwin explained evolution for the first time
- The implication of placing organisms into a particular taxon
- They are related to each other evolutionarily and share a common ancestor.
Ernst Haekel’s influence on the Kingdom system
Added Protista as a Kingdom (1866)
Robert Whittaker’s influence on the Kingdom system of classification
Added Fungi and Monera (Bacteria) as Kingdoms (1969)
Whittaker’s five Kingdoms
- Monera (Bacteria)
- Protista
- Fungi
- Plantae
- Animalia
Carl Woese’s influence on modern taxonomy
- The three Domain System
- Recognised two major groups of bacteria rather than just one
The three domains
- Archaebacteria
- Bacteria
- Eukaryotes
Bacteria Domain vs the Archaebacteria Domain
- Bacteria includes most single celled prokaryotes
- Archaebacteria includes unique bacterial prokaryotes that typically live in extreme environments such as icy cold
- Archaebacteria are considered ancient life forms that evolved separately from bacteria
Prokaryotes
- Do not have true nuclei
- DNA not enclosed by a membrane
- No true organelles
- The Bacteria and Archaebacteria are Prokaryotes
Eukaryotes
- Organisms with cells that have true nuclei
- DNA enclosed by nuclear membrane
- Cells contain true organelles
- All Eukarya are Eukaryotes
Kingdoms in the Eukarya Domain
- Protista
- Fungi
- Plantae
- Animalia
General characteriatics of the Bacteria
- Unicellular
- Prokaryotes
- Cell walls
- Some autotrophic (photosynthesis) e.g. blue-green algae
- Some heterotrophic parasites, saprotrophs or mutualists
- Asexual reproduction binary fission
Binary Fission by bacteria
A single cell divides intotwo cells with identical DNA in each
Parasitic
Dependent on living organic matter for food where the other organism is harmed
Saprotrophic
Dependent on dead organic matter for food
Mutualistic
- Living together with other organisms, so that both benefit from the relationship
- e.g. bacteria in the human digestive system
General characteristics of the Protista
- All Eukaryotes
- Reproduction either sexually or asexually
- Aquatic
- Protozoa: Anima-like, unicellular and heterotrophic
- Algae: Plant-like, autotrophic
- Slime and water moulds: Fungi like, heterotrophic
General characteristics of Fungi
- All Eukaryotic
- Heterotrophic
- Parasites, saprotrophs or mutualists
- Unicellular or multicellular
- Cell walls made of chitin and cellulose
- Bodies consist of hyphe
- Reproduction asexually or sexually (spores or gametes)
General characteristics of Plantae
- All Eukaryotes
- Autotropic, using photosynthesis
- Multicellular and complex
- Cell walls of cellulose
- Reproduce sexually (spores and gametes) and asexually (specialised outgrowts)
General characteristics of Animalia
- All Eukaryotes
- Multicellular and complex
- All heterotrophs and depend on other organisms for food (feeding)
- Do not have cell walls
- Reproduction mostly sexual (gametes) and sometimes asexual
Example Bacteria
- Lactobacillus sp. (in yogurt)
- Escherichia coli (in your intestines)
Example Protista
- Amoeba (an animal-like Protist in ponds)
- Sea Lettuce (plant-like algae on the rocky shore)
Example Fungi
- Yeast (used to make bread and beer)
- Mushrooms (the reproductive parts we sometimes eat)
- Moulds (sometimes grows on stale bread)
Divisions in Plantae
- Bryophytes (e.g. mosses)
- Pteridophytes (e.g. ferns)
- Gymnosperms (e.g. conifers)
- Angiosperms (flowering plants)
Phyla in Animalia
- Porifera (e.g. sponges)
- Cnidaria (e.g. jelly fish)
- Platyhelminthes (e.g. flatworms)
- Annelida (e.g. earthworms)
- Arthropoda (e.g. insects)
- Chordata (all vertebrates)
Biological keys
- Instruments used to identify living oganisms
- They consist of a series of options that lead the user too the correct taxon name (identification)
Dichotymous keys
- A key with two choices at each step.
- At each step two statements are given as options based on characteristics you can see on the organism needing to be identified.
- If you choose the right option at each step, it will lead to the correct taxon name.
