Biodiversity Biodiversity Video (6 min) BIODIVERSITY is the range and number of organisms found in a single place A forest has 15 different species with 100 individuals of 1 species and 1 individual of each of the other 14 species. Another forest also has 15 species, but this one has 7 individuals of each of the 15 species. Which is more diverse? The spread of individuals between species is more important than the total number of individuals in a habitat. Biodiversity can be explored at three different levels: Genetic diversity, Species diversity and Habitat diversity

Isolation What causes isolation? Example – Svladbard Reindeer Physical - Earthquakes, volcanoes, flooding, other catastrophes Social – emigration (ex: movement from a continent to a island) Example – Svladbard Reindeer

Svalbard Reindeer Svalbard is an ancient island within the Arctic circle (1100 km from the North Pole) During the last Ice Age it was connected to the mainland

Svalbard Reindeer Island Conditions Permanent ice covers much of Svalbard Only coastal lowlands see melt in summer Snow melt causes erosion of limited soil cover Short growing period No trees Wind and frost make it difficult for plants Few animals other than Svalbard reindeer have colonized the island No large predators

Mainland Reindeer (Rangifer tarandus) Live in herds Thick fur insulates against winter Lack of social interaction within herds Dig through snow with large feet during winter In winter survive eating lichen In summer eat a wide variety of plants Long heads with eyes set back to spot predators when grazing Living in herds give protection but increases competition for food Starve in summer Affected by parasitic warble fly Svalbard Reindeer (Rangifer tarandus platyrhynchus) Live singularly or in small groups due to lack of predators Smaller and more squat (galloping inefficient) Less competition for food Smaller antlers lost in winter Feed on tough vascular plants year round Large adapted stomachs with unique microorganisms to help digest poor diet Put on fat stores during summer to survive harsh winter Few parasites because of living in small numbers

Rainforests

Rainforest 28% of world’s oxygen turnover (CO2 →O2) Huge amount of biodiversity 40-75% of all species Large numbers of species endemic to area

Rainforests

Rainforests Most species have evolved to inhabit very specialized niches in their environment When humans disrupt that environment, many species cannot survive Humans have destroyed/disturbed about half of these forests Because species depend on each other in a complicated web of relationships, changing just one part of the web harms the entire ecosystem This breakdown of rainforest ecosystems will likely lead to the disappearance of up to 10% of the world’s species within the next 25 years

Rainforests Humans depend on the rainforest’s millions of life forms for its own existence The genetic diversity provides invaluable additions to the gene pool which help maintain and improve domestic crops Without a diversity of strains, crops become overly homogenous and vulnerable

Rainforest Disruption The projected major harmful effects: Reduce Earth’s vital biodiversity Destroying/degrading the habitats of unique organisms Accelerate climate change due to global warming Reduction of CO2 consumption Alter regional climate patterns to prevent return of diverse forests in cleared lands