Biodiversity and Conservation Study Notes

If an alien were to visit Earth, the diversity of life would amaze and baffle them.
The richness of living organisms on Earth continuously astonishes humans.
There are over 20,000 species of ants, 300,000 species of beetles, 28,000 species of fishes, and nearly 20,000 species of orchids.

Biodiversity is a term popularized by sociobiologist Edward Wilson, describing the combined diversity at all biological organization levels.

Biodiversity exists at multiple levels, including:
1. Genetic Diversity: Variability within a species. E.g., Rauwolfia vomitoria shows genetic diversity across Himalayan ranges in the potency of the chemical reserpine.
- India has over 50,000 genetically different rice strains and 1,000 mango varieties.
1. Species Diversity: Variation at the species level. Example: Western Ghats have more amphibian species than Eastern Ghats.
2. Ecological Diversity: Variety at the ecosystem level; India has more ecosystem diversity (e.g., deserts, rainforests) than Norway.

If current species loss rates continue, we may lose immense biological wealth in less than 200 years.
Biodiversity conservation is now a significant global issue due to its critical importance for survival and well-being.

As of 2004, the total described species (plants and animals) is slightly over 1.5 million.
Estimates of undiscovered species vary considerably from 20 million to 50 million, with Robert May's conservative estimate around 7 million.

Approximately 70% of all recorded species are animals; plants comprise 22%.
Insects account for over 70% of animal species, indicating their massive diversification.
Fungi species exceed the total of fishes, amphibians, reptiles, and mammals.
Data for prokaryotes is unclear due to the challenges in identification and culturing.

India represents 2.4% of the global land area but has 8.1% of global species diversity.
Approximately 45,000 plant species and twice as many animal species have been recorded.
Estimated that more than 100,000 plant species and over 300,000 animal species may still remain undiscovered in India.

Diversity decreases from the equator toward the poles.
- Example: Colombia has 1,400 bird species; New York has 105, and Greenland has 56.
- Tropical forests can have up to ten times the vascular plant diversity of temperate regions.
- The Amazon rainforest hosts over 40,000 plant species and immense animal diversity.

Time: Tropics have had more uninterrupted evolutionary time.
Stability: Tropical environments are less seasonal, leading to niche specialization.
Solar Energy: More solar energy in the tropics supports productivity, contributing to diversity.

Observed by Alexander von Humboldt: species richness increases with area up to a limit.
The relationship is a rectangular hyperbola expressed as: $ext{log} S = ext{log} C + Z ext{log} A$
- Where:
- $S$ = Species richness
- $A$ = Area
- $Z$ = slope (regression coefficient)
- $C$ = Y-intercept
For diverse taxa, $Z$ typically falls between 0.1 and 0.2, steeper for larger areas.

The relationship between species number and ecosystem functioning is complex but critical:
- Stability: Communities with high species richness tend to be more stable over time.
- Resilience: Such communities are resilient to disturbances and resistant to invasions.
Tilman's Experiments: Increased diversity correlates with higher productivity and reduced biomass variation.

Rapid loss of biodiversity primarily due to human actions leading to extinction.
Examples include the extinction of over 2,000 native bird species in Pacific Islands due to colonization.
IUCN Red List notes 784 species extinct in the last 500 years.
Rates of extinction are 100 to 1,000 times higher than pre-human times, leading to a projected potential loss of nearly half of all species within the next 100 years.

Habitat Loss and Fragmentation: Especially poignant in tropical rainforests, which have shrunk dramatically.
Over-exploitation: Unsustainable harvesting of species for food, timber, and other resources.
Alien Species Invasions: Introduction of non-native species can decimate local populations (e.g., Nile perch in Lake Victoria).
Co-extinctions: The extinction of one species leading to the extinction of its associated species.

Reasons for conserving biodiversity include:
- Utilitarian: Direct benefits (food, medicine, materials).
- Ecosystem Services: Benefits such as pollination, climate regulation, etc.
- Ethical Obligations: Responsibility to protect all species and ecosystems.

Protect ecosystems to preserve overall biodiversity (e.g., national parks, biosphere reserves).
Biodiversity Hotspots: Areas of high species richness facing threats. Currently, there are 34 identified hotspots including regions like the Western Ghats and Himalayas.

Remove endangered species from their habitats to protect them (e.g., botanical gardens, zoological parks).
Advanced techniques: cryopreservation for gametes, in vitro fertilization, and tissue culture methods.
Collective Responsibility: International cooperation is essential for effective biodiversity conservation. The historic Convention on Biological Diversity highlights this global challenge.

Biodiversity, essential for ecosystem health, includes genetic, species, and ecosystem diversity.
The extinction rate is drastically higher now than historically due to human activity.
Efforts must focus on in situ and ex situ conservation strategies to protect biodiversity for future generations.

Identify the three components of biodiversity.
Discuss methods ecologists use to estimate the number of species.
Explain the hypotheses for species richness in the tropics.
Analyze the significance of the species-area relationship slope.
Describe the major causes of biodiversity loss.
Discuss how biodiversity impacts ecosystem function.
Define sacred groves and their conservation role.
Illustrate how ecosystem services, such as flood control, are achieved.
Discuss potential explanations for higher species diversity in animals compared to plants.
Justify an intentional species extinction scenario.