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 humanimpacts 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
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