Biodiversity

• There are currently 1.75 million described species, but there are probably 13-14 million species in total, with most undiscovered species being invertebrates
• Coral reefs, tropical forests, and the deep ocean are the main sources of biodiversity
• Greater species diversity leads to a healthier ecosystem
• Ecosystem services (cultural, regulatory, or supportive) are only possible if biodiversity is maintained
• Organisms do not exist in isolation, and symbiotic relationships (e.g., insects & flowers) and predator-prey relationships (e.g., sea otters & urchins) contribute to ecosystem stability
• Each population has a role (niche) in an ecosystem, contributing to biogeochemical cycles and acting as bio-filters
• Genetic diversity is important because each species has a unique set of genes that code for proteins, control behaviors, and provide solutions to environmental changes
• Species diversity equals genetic diversity, and diverse ecosystems have a greater diversity of gene pools, making them more stable and adaptable to environmental changes
• High genetic diversity is important for the survival of coniferous forests and other ecosystems in the face of diseases and fungal infestations
• Monocultures with low genetic diversity are vulnerable to pests and diseases
• Genetic diversity is scientifically important for gene transfer to improve crops and cure diseases
• Biodiversity provides benefits such as food sources, raw material for genetic engineering, and the basis for drugs and medicines
• Organisms have aesthetic, ethical, and religious value, contributing to recreation, ecotourism, and religious practices
• Natural disturbances to biodiversity include background extinction, volcanic eruptions, ecological succession, and mass extinction events
• Mass extinction events are caused by factors like asteroid impacts, climate change, ocean acidification, and potentially anthropogenic activities
• Endangered species are those with so few individuals that they may become extinct soon, while threatened species have declining numbers and are likely to become extinct
• Characteristics of endangered or threatened species include extremely localized range, low reproductive success, endemism, and low adaptability or extreme specialization
• Direct causes of habitat loss and fragmentation, invasive species, hunting, poaching, capture and sale of exotics, overfishing, predator and pest control, and climate change impact biodiversity
• Habitat fragmentation leads to barriers to dispersal, genetic isolation, inbreeding, and edge effects like pesticides, diseases, and predation by domestic animals
• Wildlife corridors are important for connecting habitat fragments and maintaining biodiversity, although they are expensive to establish and maintain
• Invasive species pose a significant threat to biodiversity by out-competing native species and lacking natural predators
• Island biogeography explains how species colonize islands, leading to unique endemic species with specialized adaptations and low genetic diversity
• The Brown Tree Snake in Guam is an example of an invasive species that disrupted the island's ecosystem, leading to the extinction of several endemic species
• Conservation efforts include human population control, protection of remaining habitats, and the establishment of wildlife corridors to maintain biodiversity
• Hot spots are areas with high endemism and significant habitat loss, requiring conservation efforts to protect endemic plant species and their habitats
• Conservation strategies involve protecting habitats through national parks, sanctuaries, refuges, and forests, with varying levels of protection
• The Endangered Species Act prohibits the trade of products from endangered species and requires the development of recovery plans based on biological considerations
• International policies like CITES aim to regulate the trade of endangered species and their products to prevent further decline in biodiversity
• The earth's biodiversity refers to all the plants and animals in the biosphere, also known as species diversity or species richness of an ecosystem
• Three objectives of studying biodiversity:

  • Understand the value of species
  • Explore human impacts of species diversity
  • Explore how to protect species richness in ecosystems
• Biodiversity is a non-renewable natural resource, and if species go extinct, they are lost forever
• Ecological impacts of removing species from an ecosystem:

  • Insects pollinators eliminated by pesticide use disrupt pollination
  • Removal of nitrogen-fixing bacteria affects soil fertility
  • Bivalves like clams and mussels removal impacts water filtration
  • Gray wolves removal disrupts predator-prey balance
• Connection between species diversity and ecosystem services:

  • Species diversity loss leads to the loss of ecosystem services provided by the system
• High species diversity leads to high genetic diversity, increasing ecosystem stability and adaptability to environmental changes
• Predictions for forest scenarios:

  • Forest with high species diversity may suffer from bark beetle infestation affecting susceptible species like white pines
  • Forest with low species diversity (clear-cut and replanted with only white pines) may face severe consequences if invaded by bark beetles
• Importance of genetic diversity:

  • Genetic diversity ensures species can adapt to environmental changes
  • Genetic diversity increases the stability of ecosystems
• Biodiversity is key to the ecotourism industry worldwide
• Difference between biological extinction and commercial extinction:

  • Biological extinction means complete loss of a species
  • Commercial extinction refers to the inability to find a species in the market
• Background extinction occurs naturally due to competition and environmental changes
• Mass extinctions differ from background extinctions by being rare, punctuated events triggered by external factors like asteroid impacts or climate change