Lecture 1 - Biosphere Biodiversity (2) PDF

UKZN School of Environmental sciences, ENVS120 - Biospheric processes L1: Introduction to biodiversity and the biosphere The biosphere is sum of all living organisms on earth: plants, animals, microorganisms, etc. classified into various species....

UKZN School of Environmental sciences, ENVS120 - Biospheric processes L1: Introduction to biodiversity and the biosphere The biosphere is sum of all living organisms on earth: plants, animals, microorganisms, etc. classified into various species. “like a skin covering the earth” – in and around the other ‘spheres’ – litho-, hydro-, and atmo- Why is the world green? What parts are not green? Is there a less life in the deserts? Is there less life in the sea?  What is living? “Living organisms” are defined by their ability to reproduce, sexually or asexually. This includes animals, plants, fungi, algae, bacteria – but not viruses (cannot reproduce themselves; they need a living organism to reproduce them)  Sexual and asexual reproduction Sexual reproduction involves the recombination of genetic information between different organisms. Asexual reproduction does not.  What is a species? Sexual reproduction can only happen between organisms belonging to the same species. Organisms belonging to two different species may reproduce and produce hybrids, but these are generally sterile. This creates reproductive barriers between species. Example: the mules  Species name Classification Acinonyx jubatus (cheetah) Genus name Common name Specific epithet Kingdom Phylum Class Order Family Genus Species  Biodiversity: known and unknown Currently on Earth there are several million species of organisms, but the precise number is unknown. Most of these are insects, plants and larger animals are comparatively few. The relationship between size and diversity The smaller, the more diverse. How many species of bacteria are there? It is difficult to define bacteria species, since their reproduction is not primarily sexual.  What is biodiversity? Biodiversity is the total diversity of life, measured as number of species or otherwise. Number of species = species diversity Number of families = familial diversity etc. Also genetic diversity etc.  Measurements of species diversity One can also measure species diversity at local, regional, global scales. Tortoises of South Africa (regional) Chersina o Chersina angulata, Bowsprit Tortoise Geochelone o Geochelone pardalis, Leopard Tortoise Local diversity: Fish, corals Homopus o Homopus aerolatus, Parrot-Beaked Cape Tortoise o Homopus boulengeri, Boulenger's Cape Tortoise o Homopus femoralis, Karroo Cape Tortoise o Homopus signatus, Speckled Cape Tortoise o Homopus bergeri, Berger's Cape Tortoise Kinixys o Kinixys belliana, Bell's Hinge-Backed Tortoise o Kinixys lobatsiana, Lobatse Hingeback Tortoise o Kinixys natalensis, Natal Hinge-Backed Tortoise o Kinixys spekii, Speke's Hingeback Tortoise Psammobates o Psammobates geometricus, Geometric Tortoise o Psammobates oculifer, Serrated Star Tortoise o Psammobates tentorius, African Tent Tortoise  Global scale Rhinos of the world: Genus CERATOTHERIUM (White rhinoceros) with the SPECIES Ceratotherium simum with two Subspecies: Ceratotherium simum simum (Southern white rhinoceros) and Ceratotherium simum cottoni (Northern white rhinoceros) Genus DICEROS (Black rhinoceros) with the SPECIES Diceros bicornis with seven Subspecies: Diceros bicornis bicornis (Drier parts of southern Africa) Diceros bicornis minor (Wetter, eastern parts of southern Africa) Diceros bicornis chobiensis (Botswana, Caprivi, western Zambia, eastern Angola) Diceros bicornis michaeli (Kenya, southern Somalia) Diceros bicornis ladoensis (Uganda, southern Sudan) Diceros bicornis brucii (Ethiopia, eastern Sudan) Diceros bicornis longpipes (Western Sudan, Chad, Central African Republic, eastern Nigeria) Genus RHINOCEROS (One-horned rhinoceros) with two SPECIES Rhinoceros unicornis (Indian rhinoceros) and Rhinoceros sondaicus (Javan rhinoceros) Genus DICERORHINUS (Two-horned rhinoceros) with the SPECIES Dicerorhinus sumatrensis (Sumatran rhinoceros) with three Subspecies: Dicerorhinus sumatrensis lasiotus (Burma) Dicerorhinus sumatrensis sumatrensis (Thailand, Malaysia, Sumatra) Dicerorhinus sumatrensis harrissoni (Brunei) Faunas and floras All animal species in a region = fauna All plant species in a region = flora “the reptile fauna of South Africa” “the flora of KZN” ->> all plants