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Biology (NCERT) - Class XII > XII Chap 15 Biodiversity > Flashcards

XII Chap 15 Biodiversity Flashcards

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1
Q

Define biodiversity

A

sum total of diversity (heterogeneity) that exists at all levels of biological organisation, from macromolecules in cells to biomes

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2
Q

Who popularized the term biodiversity?

A

Edward Wilson

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3
Q

What are the 3 levels of biodiversity?

A

Genetic
Species
Ecological

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4
Q

What is genetic diversity?

A

Single species, high diversity at genetic level over its distributional range
e.g. India has 50,000 genetic strains of rice, mango - 1000

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5
Q

Western Ghats have greater _______________ than Easter Ghats

A

amphibian species level diversity

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6
Q

How many species are there on earth?

A

1.5 million discovered as per IUCN

7 million as per Robert May’s estimates

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7
Q

What percent of species are already discovered?

A

22%

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8
Q

More than 70% of recorded species are ________, and 70% of those are ________

A

animals;

insects

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9
Q

There are more fungi species in the world than ________ combined

A

vertebrates

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10
Q

__________ are the largest portion of identified species (more than 75%) among invertebrates

A

Insects

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11
Q

Half of identified species in vertebrates are _________

A

fishes

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12
Q

__________ comprise 22% of total species on earth

A

Plant species;

Fungi, algae, bryophytes, gymnosperms, angiosperms

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13
Q

7 out of 10 animals on this planet are _______

A

insects

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14
Q

Which are the two largest number of species in plants?

A

Fungi and Angiosperms

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15
Q

The estimates for number of species on the earth leave out which important group of organisms?

A

Prokaryotes

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16
Q

India has _____% of the world’s land and ____% of the global species diversity

A
  1. 4;

8. 1

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17
Q

India is one of 12 __________ countries of the world

A

mega diversity

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18
Q

What are the patterns of biodiversity?

A

Latitudinal gradient

Species-area relationship

19
Q

Explain the latitudinal gradient pattern of biodiversity

A

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

20
Q

____________ has the greatest biodiversity on Earth

A

Amazonian rain forest (S. America)

21
Q

Why do tropics have greater diversity?

A
  1. Undisturbed for millions of years (speciation takes time)
  2. More stable/constant environment (fewer seasons)
  3. More solar energy => higher productivity
22
Q

Explain species-area relationship

A

observed by Alexander von Humboldt,

species richness increases with increasing explored area but to a limit => rectangular hyperbola

23
Q

On logarithmic scale, species-area relationships is a ________ line.
What’s the formula?

A

straight;

log S(Species richness) =
log C(Y-intercept) + Z(slope) * log A (Area)
24
Q

Regardless of taxonomic group or region, Z lies in range of ________ ????? for regions;
and _______ if you look at larger areas like continents

A
  1. 1-0.2;

0. 6-1.2

25
Q

What does a biologically stable community look like?

A
  1. Almost constant (high) productivity year-on-year
  2. Resistant or resilient to occasional disturbances (man-made or natural)
  3. Resistant to biological invasion
26
Q

Tilman found that _____?

A

more species diversity => more ecosystem stability, less YoY variation, more productivity

27
Q

What is the name of the analogical hypothesis that explains significance of stability in biological ecosystem?

Who developed it?

A

Rivet popper hypothesis;

Stanford ecologist Paul Ehrlich

28
Q

_______ group is more vulnerable to extinction

A

Amphibians

29
Q

_____ species in India and _____ worldwide face extinction

A

650;

15,500

30
Q

______ species have become extinct in recent times

A

700

31
Q

There have been how many episodes of mass extinction of species on earth?

A

5, sixth in progress

32
Q

Current rate of extinction of species is ____ to ____ times faster than pre-human times

A

100 to 1,000

33
Q

Loss of biodiversity leads to

A
  1. decline in plant production
  2. lowered resistance to environmental disturbances e.g. drought
  3. increased variability in ecosystem processes e.g. plant productivity, water use, pest and disease cycles
34
Q

What is the Evil Quartet?

A

Four major causes of biodiversity loss

  1. Habitat loss / fragmentation e.g. 12 to 6% cover of Amazon
  2. Over-exploitation e.g. overharvesting fish
  3. Alien species invasions e.g. invasive weeds like Parthenium
  4. Co-extinctions e.g. plant-pollinators
35
Q

3 reasons for conserving biodiversity?

A
  1. Narrowly utilitarian: food, industrial products, medicines
  2. Broadly utilitarian: Amazon => 20% of total atmospheric oxygen, pollination, aesthetic pleasures
  3. Ethical: moral duty to other organisms and future gens
36
Q

What is bioprospecting?

A

exploring molecular, genetic and species-level diversity for products of economic importance

37
Q

____ percent of drugs come from plants

A

> 25%

38
Q

What is endemism?

A

Species confined to region and not found anywhere else

39
Q

Two types of conservation approaches?

A

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
40
Q

There are ____ biosphere reserves, ____ national parks, ____ wildlife sanctuaries in India

A

14 biosphere reserves, 90 national parks, >450 wildlife sanctuaries

41
Q

What are sacred groves?

A

Venerated trees and wildlife e.g. Meghalaya

42
Q

What are the 3 biodiversity hotspots in the Indian subcontinent?

A

Western Ghats-Sri Lanka,
Himalaya,
Indo-Burma

43
Q

All the biodiversity hotspots in the world cover ____% of earth’s land area and protection could decrease mass extinctions by _____%

A

2%

30%

44
Q

India has _______ species of plants and ______ of animals

A

45,000 plants

~90,000 animals

Biology (NCERT) - Class XII (18 decks)

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