Environmental Science 101
Totality of genes, species and ecosystems of a region.
Taxonomic or Species Level Diversity: number of different species present in a given ecosystem.
Genetic or Morphological Diversity: total number of genetic characteristics in the genetic makeup of a species.
Functional Diversity: Variety of species with unique traits or activities: locomotion, gathering of resources, reproduction, diurnal or annual activity.
- versus Functional redundancy
Ecosystem Diversity: Ecosystem variation found in a region or the whole planet.
Importance of Biodiversity
Variation within a species creates stability.
Increases likelihood species can adapt and survive environmental pressures.
Greater interdependence increases stability in ecosystems.
Increases ecosystem productivity.
Protect freshwater resources.
Promote soils formation and protection.
Provide for nutrient storage and recycling.
Aid in breaking down pollutants.
Speed recovery from natural disasters.
Provide more food resources.
Provide more medicinal and drug resources.
Offer environments for recreation and tourism.
Not evenly distributed.
Latitudinal Gradient: General increase in biodiversity from the poles to the tropics
Biodiversity today is result of 3.5 b.y. of evolution.
Marine Phanerozoic Era biodiversity history.
Fossil record suggests recent greatest biodiversity.
Problem: uncertainty as to how strongly record is biased by greater availability and preservation of recent geologic deposits.
Zero-Force Evolutionary Law: In the absence of other forces, diversity will increase over time as neutral mutations accumulate. (McShea and Brandon, 2010. Biology’s First Law)
Number of Species
Taxonomic or Species Level Diversity
According to Mora et al. (2011) there are an estimated 10.9 million species on Earth.
- 8.7 million terrestrial species; 2.2 million marine species
- Only 1.5 million species have been formally described.
Larsen et al. (2017) estimates 2 billion species.
Locey and Lennon (2016) estimates anywhere from 100 billion to 1 trillion species.
So…how many species are there on Earth?
Usually plotted as taxonomic richness of a geographic area
- Species richness: number of different species in an area
- Simpson index: number of different types in an area, and accounts for how evenness of type distribution.
- Shannon-Wiener index
Species Density: the number of species in an area
Phylogenic Density: measures phylogenetic relationships among species
Functional Diversity: measures information on functional traits among species
The Sixth Extinction
Species Loss Rates
Background Extinction Rate:
- Estimated to be between 1 to 10 species every year (out of 10 million species) = 0.0001% to 0.00001% per year
- Based on fossil records
Recent extinctions rates are best known for land vertebrates (mammals and birds).
- 80 well-documented mammal extinctions since 1500 A.D.
- Estimated to be 2 species per year, or 0.01% per year
If other taxa have similar extinction rates…
Current extinction rate is 100 to 1000 times greater than Background Extinction Rate.
Benefits that humans gain from natural environment and ecosystems.
Supporting Services: ecosystem support processes
Provisioning Services: Providing resources for human use
Regulating Services: Regulating environmental impacts
Cultural Services: Providing human life enrichment and fulfillment
Ecosystem support processes
Nutrient Cycling: Movement and exchange of organic and inorganic matter (ex. carbon cycle, nitrogen cycle, hydrologic cycle, oxygen cycle); decomposition.
Primary Production: Synthesis of organic compounds from carbon dioxide. Principally occurs through photosynthesis, but also chemosynthesis.
Soil Formation: Mixture of organic matter, minerals, gases, liquids, and organisms that together support life.
Providing resources for human use
Food: seafood, game, crops, wild foods, and spices
Raw Materials: lumber, skins, fuel wood, organic matter, fodder, and fertilizer
Biogenic Minerals: process by which living organisms produce minerals (ex. bones, shells)
Medicinal Resources: pharmaceuticals, herbs, folk remedies
Energy: hydropower, biomass fuels, animals
Ornamental Resources: fashion, handicraft, jewelry, pets, decoration and souvenirs furs, feathers, ivory, orchids, butterflies, aquarium fish, shells, etc.
Regulating environmental impacts
Carbon Sequestration & Climate Regulation: Currently, biosphere is a net sink of carbon, absorbing approximately 20% of fossil fuel emissions.
Waste Decomposition and Detoxification: Ex. Purification of water and air.
Pest and Disease Control: Deforestation, encroachment, urbanization, agriculture have been shown to increase the incidence or exposure to certain diseases and disease vectors.
Natural Hazard Regulation: Soils store large amounts of water, preventing or reducing flooding. Barrier beaches, wetlands, and lakes attenuate floods by storing & absorbing runoff peaks and storm surges.
Providing enrichment and fulfillment
Cultural: Use of nature in books, film, painting, folklore, national symbols, architect, advertising
Spiritual: Nature in religion (ex. Animism)
Recreational: Ecotourism, outdoor sports, and camping
Science Education: School excursions, and scientific discovery
Therapeutic: Ecotherapy, social forestry, animal assisted therapy