Biodiversity and Conservation Flashcards

Introduction

• The chapter discusses biodiversity and conservation.

• Aliens visiting Earth would be amazed by the diversity of life.

• Even humans are astonished by the rich variety of living organisms.

• Examples given:

  • 20,000 species of ants

  • 300,000 species of beetles

  • 28,000 species of fishes

  • 20,000 species of orchids

• Ecologists and evolutionary biologists seek to understand the significance of this diversity and how to protect it.

Biodiversity

• Biodiversity exists at all levels of biological organization, from macromolecules to biomes.

• Edward Wilson popularized the term biodiversity.

• Biodiversity is divided into three main categories:

  • Genetic diversity

  • Species diversity

  • Ecological diversity

Genetic Diversity

• Genetic diversity occurs within a single species.

• Example: Mangoes - Totapuri, Alfonso etc are different variants.

• Example: Rice ranges from Rs. 30 to Rs. 100. Basmati, short rice, rice for Idli

• Rauwolfia vomitoria (Devil's pepper):

  • A medicinal plant with varying potency and concentration of active chemical (reserpine) depending on where it grows in the Himalayas.

  • Different Himalayan ranges show different chemical concentrations.

• India has:

  • 50,000 genetically different strains of rice.

  • 1,000 varieties of mangoes.

Species Diversity

• Diversity at the species level.

• Example: Western Ghats have greater amphibian species diversity than the Eastern Ghats.

Ecological Diversity

• Diversity at the ecosystem level.

• Example: India has deserts, rainforests, mangroves, coral reefs, wetlands, estuaries, and alpine meadows, showing greater ecosystem diversity than a Scandinavian country like Norway.

• Millions of years of evolution have accumulated this diversity.

• This diversity could be lost in less than two centuries if the present rate of species loss continues.

• Biodiversity conservation is a vital environmental issue for international concern due to its critical importance for survival and well-being.

How Many Species Are There on Earth and in India?

• Published records exist for all discovered and named species.

• hard to answer question due to unexplored places.

• IUCN states approximately 1.5 million species plants and animals. Many more unidsentified.

• Species inventories are more complete in temperate countries than in tropical countries because species diversity is higher in tropical countries.

• Biologists use statistical comparisons of temperate and tropical species richness to estimate total species numbers.

• Estimates range widely, from 20 to 50 million.

• Robert May estimates global species diversity at 7 million.

• Over 70% of all recorded species are animals, while plants (including algae, fungi, bryophytes, gymnosperms, and angiosperms) comprise not more than 22%.

• Insects are the most species-rich taxonomic group among animals, making up more than 70% of the total.

• Number of fungi species is more than the combined total of species of fishes, amphibians, reptiles, and mammals.

• Diagrams illustrate the proportion of species within different groups (invertebrates, vertebrates, plants).

• Estimates do not include prokaryotes due to difficulties in identifying and culturing them.

• India has only 2.4% of the world's land area but shares 8.1% of global species diversity, making it one of the 12 mega diversity countries.

• Nearly 45,000 species of plants and twice the number of animals have been recorded in India.

• Applying Robert May's estimate, only 22% of total species have been recorded so far.

• India likely has more than one lakh plant species and more than three lakh animal species yet to be discovered.

• It is nearly impossible to complete the inventory of biological wealth due to lack of expertise and the rate at which species are becoming extinct.

• According to Robert May, the global species diversity is about 7,000,000.

Patterns of Biodiversity

• Diversity varies throughout the world.

• Latitudinal gradients exist in diversity.

Latitudinal Gradients

• Species diversity decreases as we move from the equator towards the poles.

• The tropics (23.5° N to 23.5° S) harbor more species than temperate or polar areas.

• Examples:

  • Colombia (near the equator) has nearly 4,400 species of birds.

  • New York (41° N) has around 105 species of birds.

  • Greenland (71° N) has only 56 species of birds.

  • India has more than 1,200 species of birds.

  • A forest in the tropical region of Ecuador has up to 10 times as many vascular plant species as a forest of equal area in the temperate regions of the Midwest USA.

• The Amazonian forest in South America has the greatest biodiversity on Earth:

  • 40,000 species of plants

  • 3,000 species of fishes

  • 1,300 species of birds

  • 427 species of mammals

  • 427 species of amphibians

  • 378 species of reptiles

  • 125,000 species of invertebrates

• The order of species abundance in the Amazon forest is invertebrates > plants > fishes > birds > amphibians and mammals > reptiles.

• Reasons for greater biological diversity in the tropics:

  • The temperature has remained constant. No glaciations. The speciation has happened much more better.

  • Stable temperatures. Species have more time to evolve.

  • Constant, predictable environment promotes niche specialization.

  • Higher solar energy leads to high productivity and greater diversity

Species-Area Relationship

• Alexander von Humboldt observed that species richness increased with increasing explored area, but only up to a limit.

• The relationship between species richness and area for various taxa (angiosperm plants, birds, bats, fishes) is a rectangular hyperbola.

• On a logarithmic scale, the relationship is a straight line described by the equation:

  • \log S = \log C + Z \log A

  • Where:

    • S = species richness

    • A = area

    • Z = slope of the line (regression coefficient)

    • C = y-intercept

• The value of Z lies in the range of 0.1 to 0.2 for a small group of species.

• For larger areas (intercontinental), the value of Z becomes higher (0.6 to 1.2).

• In species area relationship is described by \log s= \log c+z \log a, what is z?
  *Answer: slope of the line.

Importance of Species Diversity to Ecosystem Functioning

• Communities with more species tend to be more stable than those with less species.

• A stable community should:

  • Not show too much variation in productivity from year to year.

  • Be resistant or resilient to occasional disturbances (natural or man-made).

  • Resist invasion by alien species.

• David Tillman's long-term ecosystem experiments showed that plots with more species had less year-to-year variation in total biomass and contributed to higher productivity.

• Rich biodiversity is essential for ecosystem health and human survival.

• Losing species can have significant impacts on ecosystem function, leading to decline in plant production, lowered resistance to environmental perturbations, and increased variability in ecosystem processes.

• Rivet Popper Hypothesis (Paul Ehrlich):

  • Analogy comparing an ecosystem to an airplane and species to rivets.

  • Removing rivets (species) may not affect flight safety (ecosystem functioning) initially, but as more and more are removed, the plane becomes dangerously weak.

  • Loss of key rivets (keystone species) on the wings is a more serious threat to flight safety than the loss of rivets on seats or windows.

Loss of Biodiversity

• The biological wealth of our planet has been declining rapidly due to human activities.

• Colonization of Tropical Pacific Islands by humans led to the extinction of more than 2,000 species of native birds.

• The IUCN Red List (2004) documents the extinction of 784 species, including 338 vertebrates, 359 invertebrates, and 87 plants in the last 500 years.

• Examples of recent extinctions include:

  • Dodo (flightless bird from Mauritius)

  • Quagga (Africa)

  • Thylacine (Australia)

  • Steller’s sea cow (Russia)

  • Three subspecies of tiger (Bali, Javan, Caspian)

• The last 20 years alone have witnessed the disappearance of 27 species.

• Extinctions across taxa are not random; some groups (amphibians) are more vulnerable.

• More than 15,500 species worldwide face the threat of extinction.

• 12% of all birds, 23% of all mammals, 32% of all amphibians, and 31% of all gymnosperm species in the world face the threat of extinction.

• Large-scale loss of species has happened before, but the current rate of extinction is estimated to be 100 to 1,000 times faster than pre-human times.

• If the present trend continues, nearly half of all species on Earth might be wiped out within the next 100 years.

• Loss of biodiversity may lead to:

  • Decline in plant production

  • Lowered resistance to environmental perturbations (drought)

  • Increased variability in ecosystem processes.

Causes of Biodiversity Loss

• Accelerated rate of species extinction is largely due to human activities.

Habitat Loss and Fragmentation

• The most important cause in driving animals and plants to extinction.

• Tropical rainforests, once covering 14% of the Earth's land surface, now cover no more than 6%.

• Amazon rainforest is being cut and cleared for cultivation of soya beans or conversion to grasslands for raising beef cattle.

• When large habitats are broken into small fragments, mammals and birds requiring large areas are badly affected, leading to population decline.

Over-exploitation

• Humans have always depended on nature for food and shelter, but when the need turns into greed = lead to over exploitation natural resources.

• Many species extinctions in the last 500 years (Steller’s sea cow, passenger pigeon) were due to overexploitation by humans.

• Presently, many marine fish populations around the world are over harvested, endangering the continued existence of some commercially important species.

Alien Species Invasions

• When alien species are introduced unintentionally or deliberately, some of them turn invasive, causing decline or extinction of indigenous species.

• Examples:

  • Nile perch introduced into Lake Victoria led to the extinction of more than 200 species of cichlid fish in the lake.

  • Invasive weeds like carrot grass (Parthenium), Lantana camara, and water hyacinth (Eichhornia) cause environmental damage and threaten native species. Lantana camera and Parthenium came as mixed weed.

  • The recent illegal introduction of African catfish (Clarias gariepinus) for aquaculture purposes is posing a threat to the indigenous catfish in our rivers.

Co-extinctions

• When a species becomes extinct, the plant and animal species associated with it in an obligatory way also become extinct.

• When a host fish species becomes extinct, its unique assemblage of parasites also meets the same fate.

• Co-evolved plant-pollinator mutualism (fig and wasp) where extinction of one invariably leads to extinction of the other.

Why Should We Conserve Biodiversity?

• Reasons for conserving biodiversity:

  • Narrowly utilitarian

  • Broadly utilitarian

  • Ethical

Narrowly Utilitarian

• Human derived, economic benefits from nature.

  • Humans derive countless direct economic benefits from nature, including food, fiber, firewood, pharmaceuticals, and more.

  • More than 25% of the drugs currently sold in the market worldwide are derived from plants, and 25,000 species of plants contribute to the traditional medicine used by native people around the world.

  • Bioprospecting (exploring molecular, genetic, and species-level diversity for products of economic importance) can lead to enormous benefits for nations with rich biodiversity.

Broadly Utilitarian

• Biodiversity plays a major role in many ecosystem services, such as:

  • The fast-dwindling Amazon rainforest is estimated to produce, through photosynthesis, 20% of the total oxygen in the Earth’s atmosphere.

  • Pollination

  • Bees; Bumble bees. Birds.

  • Aesthetic pleasure of walking through a thick wood and the pleasure of watching spring flowers in full bloom.

Ethical

• Conserving biodiversity relates to what we owe to millions of plants, animals, and microbe species with whom we share the planet.

• There is intrinsic value in every species. We should not be greedy.

• We have a moral duty to care for their well-being and pass on our biological legacy in good order to future generations.

How Do We Conserve Biodiversity?

• In Situ conservation. We save the entire forest to save an animal. Conserving biology. The entire level is predicted in this approach.

  • Conserving and protecting the whole ecosystem protects biodiversity at all levels.

    • Saving an entire forest is more effective than saving a single tiger.

      • It is your on site conversion

      • Biosphere reserves

      • National parks

      • San ctiaies

• Ex Situ Conservation. Keep it in a specialized setting. Protected.
  In the wild (botanical gardens, etc)
  Threatened risk extinction needs argent to be saved fro extinction

• In the in-situ region, the first is your biosphere reserve.

• Second one is your national parks.

• Then were sanctuaries.

• Biodiversity hotspots

  • Located in which the species richness is enriched and high degree and endemism.
    *Regions of accelerated habitat loss.

• The current number of biodiversity spots is 34.
  *Protected by strict law.
  Three of them India
  *Unique biodiversity
  *In India, ecologically unique biologically protected region are legally protected biosphere
  * India has a history of religious and cultural importance, protecting the nature
  * Sacred grows

• Khasi and janita hulls and Meghalays

• Exta culture approach to a threatened animal.
  *Zoo logical parks
  *Botanical gardens
  What the safari parks. serve the purpose.

  • Preserve the genetic strains using a cryo preservation (liquid nitrogen)
    *The Rio to janeiro conference called for to take appreciate measure the conservation and sustainable utilization.

The most prominent part of this chapter is
*Habitat loss
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