XII Chap 15 Biodiversity Flashcards
Define biodiversity
sum total of diversity (heterogeneity) that exists at all levels of biological organisation, from macromolecules in cells to biomes
Who popularized the term biodiversity?
Edward Wilson
What are the 3 levels of biodiversity?
Genetic
Species
Ecological
What is genetic diversity?
Single species, high diversity at genetic level over its distributional range
e.g. India has 50,000 genetic strains of rice, mango - 1000
Western Ghats have greater _______________ than Easter Ghats
amphibian species level diversity
How many species are there on earth?
1.5 million discovered as per IUCN
7 million as per Robert May’s estimates
What percent of species are already discovered?
22%
More than 70% of recorded species are ________, and 70% of those are ________
animals;
insects
There are more fungi species in the world than ________ combined
vertebrates
__________ are the largest portion of identified species (more than 75%) among invertebrates
Insects
Half of identified species in vertebrates are _________
fishes
__________ comprise 22% of total species on earth
Plant species;
Fungi, algae, bryophytes, gymnosperms, angiosperms
7 out of 10 animals on this planet are _______
insects
Which are the two largest number of species in plants?
Fungi and Angiosperms
The estimates for number of species on the earth leave out which important group of organisms?
Prokaryotes
India has _____% of the world’s land and ____% of the global species diversity
- 4;
8. 1
India is one of 12 __________ countries of the world
mega diversity
What are the patterns of biodiversity?
Latitudinal gradient
Species-area relationship
Explain the latitudinal gradient pattern of biodiversity
Tropics (lat 23.5°N to 23.5°S) have more species than temperate or polar regions; diversity decreases as you move from equator to poles
____________ has the greatest biodiversity on Earth
Amazonian rain forest (S. America)
Why do tropics have greater diversity?
- Undisturbed for millions of years (speciation takes time)
- More stable/constant environment (fewer seasons)
- More solar energy => higher productivity
Explain species-area relationship
observed by Alexander von Humboldt,
species richness increases with increasing explored area but to a limit => rectangular hyperbola
On logarithmic scale, species-area relationships is a ________ line.
What’s the formula?
straight;
log S(Species richness) = log C(Y-intercept) + Z(slope) * log A (Area)
Regardless of taxonomic group or region, Z lies in range of ________ ????? for regions;
and _______ if you look at larger areas like continents
- 1-0.2;
0. 6-1.2
What does a biologically stable community look like?
- Almost constant (high) productivity year-on-year
- Resistant or resilient to occasional disturbances (man-made or natural)
- Resistant to biological invasion
Tilman found that _____?
more species diversity => more ecosystem stability, less YoY variation, more productivity
What is the name of the analogical hypothesis that explains significance of stability in biological ecosystem?
Who developed it?
Rivet popper hypothesis;
Stanford ecologist Paul Ehrlich
_______ group is more vulnerable to extinction
Amphibians
_____ species in India and _____ worldwide face extinction
650;
15,500
______ species have become extinct in recent times
700
There have been how many episodes of mass extinction of species on earth?
5, sixth in progress
Current rate of extinction of species is ____ to ____ times faster than pre-human times
100 to 1,000
Loss of biodiversity leads to
- decline in plant production
- lowered resistance to environmental disturbances e.g. drought
- increased variability in ecosystem processes e.g. plant productivity, water use, pest and disease cycles
What is the Evil Quartet?
Four major causes of biodiversity loss
- Habitat loss / fragmentation e.g. 12 to 6% cover of Amazon
- Over-exploitation e.g. overharvesting fish
- Alien species invasions e.g. invasive weeds like Parthenium
- Co-extinctions e.g. plant-pollinators
3 reasons for conserving biodiversity?
- Narrowly utilitarian: food, industrial products, medicines
- Broadly utilitarian: Amazon => 20% of total atmospheric oxygen, pollination, aesthetic pleasures
- Ethical: moral duty to other organisms and future gens
What is bioprospecting?
exploring molecular, genetic and species-level diversity for products of economic importance
____ percent of drugs come from plants
> 25%
What is endemism?
Species confined to region and not found anywhere else
Two types of conservation approaches?
In situ (on site) - if it’s a biodiversity hotspot (34 globally) or high degree of endemism
Ex situ (off-site) - if endangered in wild zoological parks, botanical gardens, wildlife safari parks + in vitro fertilisation, tissue culture propagation, seed banks and cryopreservation of gametes
There are ____ biosphere reserves, ____ national parks, ____ wildlife sanctuaries in India
14 biosphere reserves, 90 national parks, >450 wildlife sanctuaries
What are sacred groves?
Venerated trees and wildlife e.g. Meghalaya
What are the 3 biodiversity hotspots in the Indian subcontinent?
Western Ghats-Sri Lanka,
Himalaya,
Indo-Burma
All the biodiversity hotspots in the world cover ____% of earth’s land area and protection could decrease mass extinctions by _____%
2%
30%
India has _______ species of plants and ______ of animals
45,000 plants
~90,000 animals
