Biodiversity

• Variations in incoming solar radiation create global climate patterns
• Earth's spherical shape causes the intensity of incoming solar radiation to vary from the equator to the poles - producing latitudinal variation in temperature
• Sunlight strikes Earth at a 90° angle near the equator, it travels the shortest possible distance through the atmosphere and falls on the smallest possible surface area

  
• Near the poles, sunlight arrives at an oblique (slanting) angle, it travels a longer distance through the atmosphere and shines on a larger area
• Variations in precipitation create global climate patterns
• The tropics (around 00 latitude) receive high annual rainfalls, whereas regions near 300 latitude (e.g., deserts) are usually dry
• Local topographic features and ocean currents also influence precipitation patterns
• Precipitation patterns determine the location of terrestrial biomes
• Varying topography in South Africa has effect on its climate
• Biodiversity refers to both the diversity of life (i.e., different species of animals, microbes & plants and their genes) and the diversity of ecosystems
• Biodiversity covers a variety of environments (e.g., terrestrial, marine [i.e., sea] and other aquatic ones [e.g., freshwater ponds, dams, etc.])
• Biodiversity is dynamic. A concept that emphasises the interrelatedness of the biological world
• Genetic diversity allows for adaptation to changing conditions
• Genes for disease resistance or those for efficient photosynthesis may lead to increased yield in agriculture, hence more profit
• Plant breeders bred virus-resistant commercial rice by crossing it with a wild population
• Photosynthesis proteins can also be genetically incorporated in ordinary rice to increase efficiency of photosynthesis hence increase in yield by 50%
• Genes for disease resistance may lead to a healthy working force that may increase productivity where they work. Their companies will then make more profit
• Medicinal prescriptions (e.g., Iberogust) may contain substances originally derived from plants
• The rosy periwinkle contains alkaloids that inhibit cancer growth. Increased productivity hence profit is normally a result of a healthy workforce (free from diseases like cancer)
• Species diversity is the variety of species in an ecosystem
• Species diversity is important in maintaining structure of communities and food webs
• Species Richness is the number of species in the community
• Species Evenness is the relative abundance of species
• Diversity is greatest when all the species present are equally abundant in the area
• Species diversity varies systematically across the globe with latitude (north-south), longitude (east-west), and altitude (or its equivalent, depth, in the oceans)
• In terrestrial groups, the higher species diversity is in the Southern Hemisphere and the tropics
• The entire Amazon ecosystem depends on Saharan dust to replenish nutrient losses, hence maintaining the high species diversity there
• Tropical rainforests support the greatest diversity of living organisms on Earth. Although they cover less than 2 percent of Earth's surface, rainforests house more than 50 percent of the plants and animals on the planet
• In most marine groups, diversity is maximal in the Indo-West Pacific
• Southern hemisphere
• Global biodiversity
• Species diversity varies systematically across the globe with latitude (parallels), longitude (meridians), and altitude (or its equivalent, depth, in the oceans)
• Endangered species

  In danger of becoming extinct throughout all or a significant portion of its range
• Critically Endangered Species

  It has/will decrease by 80% within 3 generations OR numbers less than 50 Mature Individuals
• Threatened species

  Likely to become endangered in the foreseeable future
• Man was/still is the main driving force behind loss of species diversity and extinctions
• Flag species

  Species that represent an environmental cause such as an ecosystem in need of conservation. They are chosen for their vulnerability or attractiveness, and they normally become icons for conservation projects based on their ecosystems and all species therein
• Keystone species

  Species that play a critical role in maintaining the structure of an ecological community relative to its population
• Keystone species

  • Keystone prey
  • Keystone predators
  • Keystone hosts
  • Keystone mutualists
  • Keystone modifiers
• The extinction of a keystone species is predicted to cause a cascade of further extinctions