What it is & why it matters. Biodiversity What it is & why it matters.

Biodiversity refers to the number and kinds of organisms on the planet; a measure of life’s diversity. genetic diversity (intraspecific) – within a species Taxonomic (interspecific) diversity = between species ecosystem diversity. Biodiversity is the source of all human food, domesticated breeds of animals and plants, as well as bio-based medicines.

Life on our planet:

Life on our planet:

A matter of perspective: Anthropocentrism = human-centred views of life, nature, the universe… We relate most to those living things that have most in common with us Familiarity: We identify things we have experienced directly… microscopic species? Numbers: 2 Million known species, but there are estimates from 10 to 100 million out there. Conservative estimate: 20 million species of life

Intraspecific Biodiversity: All members of a species are different, due to differences in their genes. Sources of genetic difference: Different Parental DNA Population Gene frequencies Gene changes – Mutations. Non-random mating Human interference

Intraspecific Biodiversity Burchell’s Zebra shows variation in striping across its natural range, yet they can all interbreed readily.

Intraspecific Biodiversity Humans have modified many animals to suit our needs or whims, yet they remain one species, capable of interbreeding with very different looking breeds of their species.

Interspecific Biodiversity: Species differ from one another because of their evolutionary ancestry A species’ family tree over time is its phylogeny. Different lineages have different genes Results in many species of similar organisms. Members of different species cannot mate with one another successfully.

Interspecific Biodiversity: The primates from the previous slide are evolved from divergent lineages all descended from some very distant common ancestor.

Interspecific Biodiversity: Over time, the ancestral forms that gave rise to the modern horse became extinct, but all were varied in their traits & adapted to changing environments.

Ecological Biodiversity: Some general trends on our planet: Closer to the equator, more species diversity Why? Stable climate, and more direct solar energy = more biomass to support the food chain. Harsh environments lead to extreme adaptations in the organisms living there Geographic Area: # of breeding bird species: Greenland 56 Labrador 81 Newfoundland 118 Eastern USA 195 Guatemala 469 Colombia 1525

Canada’s Biodiversity: Group Known Species Est. Still Unrecorded Fungi 11800 3800 Plants 4934 135 Molluscs 1500 Arachnids 3275 7730 Crustaceans 3139 1400 Insects 18350 Fish 1100 513 Reptiles 42 Birds 426 Mammals 194

Canada’s Biodiversity:

Global Biodiversity: Distribution of Bird Species

Global Biodiversity: Distribution of Plant Species

Global Biodiversity: Distribution of Mammal Species

Global Biodiversity: Biodiversity Hotspots

Threats to Biodiversity Mainly habitat loss or damage, due to human population expansion. Estimated 2700 species can become extinct in a year…. That’s 3 per hour! Our impact is not new: Humans colonizing North America 15000 years ago led to the extinction of species such as the horse, mammoth, sabre-tooth cat, and camel. Similar impact when humans settled Polynesia 10000 years ago, New Zealand 1000 AD., Madagascar 500 AD…

Why Biodiversity Matters Ecosystems need all of their organisms. Losing one or two species might create a domino effect of collapse. Our food supply depends on diversity. “Useful products can not be harvested from extinct species. If dwindling wildlands are mined for genetic material rather than destroyed for a few more tons of lumber or acrage of farmland, their economic yield will be vastly greater over time. Salvaged species can help to revitalize timbering, agriculture, medicine, and other industries.” – E. Wilson, Diversity of Life