Ecology 1 Biogeography PDF

Tundra Caribou TRF Biogeography – the study of the distribution of plants and animals over the Earth’s surface Tiger Taiga Grassland ...

Tundra Caribou TRF Biogeography – the study of the distribution of plants and animals over the Earth’s surface Tiger Taiga Grassland  Ecology From the Greek word ‘Oikos’ meaning home Is the study of the inter-relationships between organisms and their habitats. Species are the different kinds of organisms found on the Earth. There are 14 million species at present Species richness in major groups of organisms. The main ‘pie’ shows the species estimated to exist in each group; the hatched area within each slice shows the proportion that have been formally described. Human Impacts on Biodiversity? There have been roughly three documented species extinctions per year since 1600, and most extinctions must have passed us by. The rate is increasing the last century saw the end of 20 mammalian species alone – it would take at least 200 centuries to redress. Habitat = home e.g. Lions (Panthera leo) primary habitat is grassy plains, savanna and open woodlands. Niche = profession the functional role of an organism in a community, its job or position. Image: lions Prey = wildebeest, zebra giraffes, buffalo and gazelles)  Ecological terms a population means all the members of a single species that live in a habitat a community means all the populations of different organisms living together in a habitat an ecosystem refers to a community of animals, plants and micro-organisms, together with the habitat where they live  Ecological Units Micro-habitats – small specific locations e.g. under a leaf or stone Habitats – e.g. more specific locations e.g. a pool, a woodland Zones – units within biomes e.g. ocean surface and ocean deep Biomes – large areas cutting across continents yet each with its own characteristic type of flora and fauna  Habitat Panthera leo Biome Biodiversity is the sum total of all biotic variation from the level of genes to ecosystems  Biodiversity Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biologists most often define biodiversity as the "totality of genes, species, and ecosystems of a region". Biological variety has traditionally been identified at 3 levels: species diversity ecosystem diversity genetic diversity In 2003 a fourth level: molecular diversity, was also recognised.  Distribution of organisms Living organisms are not evenly distributed around the world, but are adapted to live in particular habitats. A number of factors affect the suitability of any habitat for the organisms that live there. The most important of these is climate, which determines the temperature range and rainfall levels in a given habitat.  Distribution of organisms Warm temperatures and plentiful water make the tropical rainforest a rich environment which is home to a huge variety of species. Deserts are sparsely populated with few species, because of the extremes of heat and cold and lack of water - conditions which few organisms are adapted to survive in. The ocean covers 71 percent of the Earth's surface The world’s seas and oceans support nearly half of all species on Earth  Biomes = major regional groupings of plants and animals at a global scale. Their distribution patterns are strongly correlated with regional climate patterns and vegetation type. A biome (also called a biotic area) may be defined as a major region of distinctive plant and animal groups well adapted to the physical environment of its distribution area. The tropical rainforest is earth's most complex biome in terms of both structure and species diversity A savanna or savannah is a mixed woodland grassland ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close A desert is a barren area of landscape where little precipitation occurs and consequently living conditions are hostile for plant and animal life The word tundra derives from the Finnish word for barren or treeless land. The tundra is the simplest biome in terms of species composition and food chains. The taiga or boreal forest exists as a nearly continuous belt of coniferous trees across North America and Eurasia. Antarctica North Pole Boreal forests are the largest “biome”, or ecosystem, anywhere on the Earth’s land surface and account for 30% of the world’s forests. They are a very important store of carbon. While there is a lot of uncertainty around the precise amount of carbon they hold, estimates suggest it is more than one third of all terrestrial carbon. And about a third of the boreal biome is underlain by permafrost. The relationship between biomes and climate. African hunting dogs are endangered There are close to a hundred different types of lemur on Madaga scar Extinct: Examples: Thylacine, Dinosaurs, Pterosaurs, Javan Tiger, Dodo, Passenger Pigeon, Caribbean Monk Seal, Steller's Sea Cow, Aurochs, Elephant Bird, Moa, Haast's Eagle, Woolly Mammoth, Woolly Rhinoceros, Dusky Seaside Sparrow, Golden Toad, Toolache Wallaby Extinct in the wild: captive individuals survive, but there is no free-living, natural population. Examples: Hawaiian Crow, Wyoming Toad, Spix's Macaw (maybe critically endangered), Socorro Dove, Scimitar Oryx, Catarina Pupfish, Barbary Lion Critically endangered: faces an extremely high risk of extinction in the immediate future. Examples: Mountain Gorilla, Bactrian Camel, Ethiopian Wolf, Saiga, Takhi, Iberian Lynx, Kakapo, Arakan Forest Turtle, Sumatran Rhinoceros, Javan Rhino, Brazilian Merganser, Axolotl, Leatherback Sea Turtle, Northern White Rhinoceros, Gharial, Vaquita, Philippine Eagle, Brown Spider Monkey, California Condor, Island Fox, Chinese Alligator, Sumatran Orangutan, Asiatic Cheetah, African Wild Ass, Hawaiian Monk Seal, Mediterranean Monk Seal, Red Wolf, Amur Leopard, Spix's Macaw (maybe extinct in the wild), Siamese Crocodile Endangered: faces a very high risk of extinction in the near future. Examples: Dhole, Blue Whale, Asian Elephant, Giant Panda, Snow Leopard, African Wild Dog, Green Sea Turtle, Malayan Tapir, Tiger, Steller's Sea Lion, Asiatic Lion, Markhor, Bornean Orangutan, Grevy's Zebra, Tasmanian Devil, Japanese Crane, Gorillas, Bonobo, Wild Water Buffalo, African Penguin, Goliath Frog, Lear's Macaw, Rothschild Giraffe, Giant Otter, Pygmy Hippopotamus, Hyacinth Macaw, Volcano Rabbit, Proboscis Monkey, Persian Leopard, Red Panda Vulnerable: faces a high risk of extinction in the medium-term. Examples: African Elephant, Cheetah, Gaur, Lion, Sloth Bear, Dugong, Polar Bear, Indian Rhinoceros, Komodo Dragon, Great White Shark, Hippopotamus, Mandrill, Fossa, Crowned Crane, Clouded Leopard, Far Eastern Curlew, Galapagos Tortoise, Mountain Zebra, Humboldt Penguin, Golden Hamster, Maned Sloth Near threatened: may be considered threatened in the near future. Examples: Eurasian Curlew, Blue-billed Duck, Solitary Eagle, American Bison, Jaguar, Leopard, Maned Wolf, Tiger Shark, Southern White Rhinoceros, Okapi, African Grey Parrot, Striped Hyena, Narwhal, Magellanic Penguin Least concern: no immediate threat to the survival of the species. Examples: Common Wood Pigeon, Rock Pigeon, Giraffe, California Sea Lion, Brown Bear, Grey Wolf, House Mouse, Scarlet Macaw, Platypus, Bald Eagle, Brown Rat, Cane Toad, Humpback Whale, Emperor Penguin, American Crow , Human Mute Swan, Mallard, Red-tailed Hawk, Indian Peafowl, American Alligator, Southern Elephant Seal, Meerkat, Cougar, Brown-throated sloth, Eurasian Lynx  Energy Flows in Ecosystems Green plants and algae are called autotrophs or producer organisms, as they capture solar energy to make sugars in the process of photosynthesis. All consumers are examples of heterotrophic organisms, as they can not make their own food using the sun, but depend upon the ingestion of other organisms for their nutrition.  Photosynthesis 6CO2 + 6H2O C6H12O6 + 6O2.  Patterns in Primary Productivity PP = rate at which biomass is produced per unit area by plants (primary producers) Total fixation of energy by photosynthesis = GPP Gross PP Some is lost as heat during Respiration R  Net Primary Production = NPP NPP = GPP – R The actual rate of production of new biomass that is available for consumption by heterotrophic organisms.  Patterns in NPP NPP is not spread evenly across the globe A large proportion of the globe (30% of the land surface and 90% of the oceans) produces less than 400gm-2/yr The open ocean = a marine desert  Trends in NPP There is a general latitudinal trend of ↑PP as near equator (as temperature and rainfall generally increase). In the oceans – nutrient limitations. ↑PP occurs where there are upwellings of nutrient-rich waters, even at high latitudes and low temperatures Ecosystem Type Area (106km2) Mean NPP (tkm-2 World NPP 109t TRF 17 2200 37.4 Tropical seasonal forest 7.5 1600 12 Temperate evergreen forest 5 1300 6.5 Temperate deciduous forest 7 1200 8.4 Boreal forest 12 800 9.6 Woodland and shrubland 8.5 700 6 Savanna 15 900 13.5 Temperate grassland 9 600 5.4 Tundra and alpine 8 140 1.1 Desert and semi-desert 18 90 1.6 Rock, sand and ice 24 3 0.07 Cultivated land 14 650 9.1 Swamp and marsh 2 2000 4 Lake and stream 2 250 0.5 Total continental 149 773 115 Open ocean 332 125 41.5 Upwelling zones 0.4 500 0.2 Continental shelf 26.6 360 9.6 Algal beds and reefs 0.6 2500 1.6 Estuaries 1.4 1500 2.1 Total marine 152 55 Full total 510 333 170  Food chain A food chain indicates the transfer of energy from producers through a series of organisms which feed upon each other Grass Food Chain Zebra Lion  Food Webs A food web is a series of interrelated food chains.. ecosystems have energy flows and ecosystems cycle materials. These two processes are linked, but they are not quite the same  Why are Big Fierce Animals rare? 10% Energy loss 10 % Energy loss 10 % Energy loss  Fewer LOSS of Organisms ENERGY Fall in biomass Secondary consumers Primary consumers Detritivores producer organisms Many at every Organisms stage Much Biomass The Energetics of the Trophic Pyramid Shorter food chains = less energy loss