Lec+5-+Biodiversity

Octopi Wall Street

  • Invertebrates for Peace: A movement proclaiming that invertebrates form 97% of animal diversity.

  • Key slogans: "Spineless not heartless!" and "End Taxonomic Greed!"

  • Brought to you by the Oregon Institute of Marine Biology, University of Oregon.

Introduction to Biodiversity

  • Borneo is home to some of the richest rainforests but has experienced significant degradation since 2002 due to logging and oil palm plantations.

  • Habitat loss has particularly impacted species like orangutans.

  • Conservation biology is emerging to address the preservation and restoration of biodiversity.

Understanding Biodiversity

  • Biodiversity defined as the tree of life, showcasing evolutionary relationships among all organisms.

  • Increases in biodiversity are depicted as adding branches and tips to this tree, while extinctions result in their removal.

Genetic Diversity

  • Genetic diversity encompasses the genetic information within a population or species.

  • Measured by the number and frequency of genes and alleles present.

  • Unique alleles can be maintained through genetic drift or natural selection.

  • It represents the adaptive capacity essential for species survival amid environmental changes.

Advances in Cataloging Genetic Diversity

  • Significant technical breakthroughs in cataloging genetic diversity:

    • Genome sequencing of multiple individuals.

    • Environmental sequencing to document diversity in soil or water samples.

Species Diversity

  • Species diversity characterized by two metrics:

  • Species richness: Count of species in an area.

  • Species diversity: Combines richness and evenness; i.e., relative abundance of each species.

  • The term "species diversity" often used interchangeably with richness.

Measuring Species Diversity

  • Traditionally measured through field studies over extended periods.

  • DNA barcoding to identify unique species based on genetic sequences.

  • High species diversity correlates with productivity and ecosystem stability.

Current Estimates of Species Diversity

  • An estimated 5 to 100 million species exist on Earth.

  • Many lineages, including bacteria and archaea, remain poorly understood.

  • New species continue to be discovered even in well-studied groups.

Mapping Species Richness and Endemism

  • Biodiversity assessed using geographical grids or regions with known endemism.

  • Areas of high species richness often overlap with high endemism, providing insightful data.

Patterns in Species Richness

  • Species richness typically highest in tropical areas and decreases towards polar regions.

  • Land biodiversity outpaces that of oceans, with geographical variation leading to greater diversity.

Biodiversity Hotspots

  • Defined as regions containing at least 1500 endemic plant species and losing 70% of native vegetation.

  • Despite covering only 2.3% of Earth’s land, hotspots account for a substantial percentage of plant species and terrestrial vertebrates.

Threats to Biodiversity

  • Current extinction rates are 100 to 1000 times higher than average background rates.

  • We are facing a possible sixth mass extinction event.

  • Over 40% of amphibians and significant percentages of birds and mammals are threatened.

Major Sources of Biodiversity Threats

  • Top threats include:

  • Habitat destruction and degradation

  • Overexploitation

  • Invasive species

  • Pollution

  • Climate change.

Habitat Destruction

  • Human activities like logging, grazing, damming, and urbanization lead to habitat destruction.

  • Deforestation is a major concern, particularly in biodiversity hotspots, exacerbating climate change effects.

Habitat Degradation

  • Activities such as pollution and fragmentation lead to habitat degradation.

  • Fragmentation can diminish genetic diversity and increase vulnerability of isolated populations.

Overexploitation

  • Defined as unsustainable removal of organisms from the environment, particularly in marine contexts.

  • A significant decline in populations of large sea fish and two-thirds of harvestable marine species is noted.

Invasive Species

  • Nonnative species that disrupt local ecosystems by competing with, preying on, or introducing diseases to native species.

Pollution

  • Chemicals from human activities alter biotic and abiotic environments, contributing to problems like acid rain and eutrophication.

Climate Change Effects

  • Leading to habitat loss, species endangerment, and altering community structure.

  • Melting ice caps and changes in ocean chemistry threaten biodiversity hotspots.

Future Extinction Rates

  • Predictions consider evolutionary impacts, abiotic factors, behavioral responses, and community interactions alongside basic population demographics.

Importance of Biodiversity

  • Biodiversity provides economic and ecological advantages, sustaining ecosystems and human welfare.

  • Ecosystem services are invaluable, estimated at $125 trillion annually.

Conservation Strategies

  • Education campaigns for public awareness.

  • Genetic restoration facilitating gene flow in endangered species.

  • Ex situ conservation in zoos and seed banks.

  • Wildlife corridors connect fragmented habitats, promoting gene flow.

Ecosystem Services Value

  • Bioprospecting and regulating services (like water purification) underline biodiversity's monetary value.

  • Cultural services integrate nature into human activities, reinforcing its intrinsic importance.

Take-Home Message

  • Urgent global environmental crises necessitate concerted efforts toward biodiversity preservation, showcasing biology's potential for positive impact.