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Biology (NCERT) - Class XII > XII Chap 13 Organisms & Populations > Flashcards

XII Chap 13 Organisms & Populations Flashcards

(101 cards)

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1
Q

__________ is the Father of Ecology in India and founded the first postgraduate course in ecology in India

A

Ramdeo Misra

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2
Q

What is ecology?

A

Subject that studies the interactions among organisms (biotic environment) and between the organism and its physical (abiotic) environment

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3
Q

What are the 4 levels of biological organisation?

A
  1. Organisms
  2. Populations
  3. Communities
  4. Biomes
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4
Q

Even our intestine is a unique habitat for hundreds of species of microbes. T or F?

A

True

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5
Q

What are the major biomes of India?

A
  1. Tropical rain forest
  2. Deciduous forest
  3. Desert
  4. Sea coast
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6
Q

Key elements that lead to variation in different habitats?

A

Temperature, water, light and soil

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7
Q

Habitat of an organism only consists of the abiotic (physio-chemical) components like temperature, water, etc.

T or F?

A

False, also comprises of the biotic components - pathogens, parasites, predators and competitors

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8
Q

What is a niche?

A

Defined range of conditions that an organism can tolerate, diversity in the resources it utilises,
distinct functional role in the ecological system

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9
Q

Temperatures range from _________ in polar areas/high altitudes to ______ in tropical deserts in the summer

A

sub-zero

> 50°C

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10
Q

What are places where temperatures exceed 100°C?

A

Thermal springs and deep-sea hydrothermal vents

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11
Q

Tuna fish are rarely caught within tropical latitudes in the ocean. T or F?

A

False, they are ONLY caught within tropical latitudes, rarely BEYOND tropical latitudes

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12
Q

How does temperature affect organisms?

A

Affects kinetics of enzymes => metabolic activity

and other physiological functions

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13
Q

What are eurythermal vs stenothermal organisms?

A

Eurythermal - can tolerate and thrive in WIDE temp ranges

Stenothermal - restricted to NARROW temp range

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14
Q

What aspects of water are important for aquatic organims?

A

Quality (chemical composition, pH) and salinity

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15
Q

What is the salinity in:

  1. inland waters
  2. sea
  3. hypersaline lagoons?
A
  1. inland waters - 5 parts per thousand
  2. sea - 30-35 parts per thousand
  3. hypersaline lagoons - >100 parts per thousand
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16
Q

What are euryhaline vs stenohaline organisms?

A

Eury - WIDE range of salinities

Steno - NARROW range

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17
Q

Many freshwater organisms cannot live for long in sea water and vice versa because of ________

A

osmotic problems

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18
Q

Small plants are optimized to photosynthesize in low light. Why?

A

Constantly overshadowed by tall trees

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19
Q

Flowers rely on sunlight to meet their ______ requirement for flowering.

A

Photoperiodic

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20
Q

How is light important for animals?

A

use the diurnal and seasonal variation in light as cues for timing their foraging, reproductive and migratory activities

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21
Q

________ quality of solar radiation is important for life

A

Spectral

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22
Q

UV component of spectrum is harmful to many organisms. T or F?

A

True

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23
Q

All colour components of visible spectrum are available for marine plants living at different depths of the ocean. T or F?

A

False, not all color components

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24
Q

Nature and properties of soil are dependent on:

A

climate
weathering process
whether soil is transported or sedimentary
how soil development occurred

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25
What characteristics determine percolation & water holding capacity of soil?
Soil composition Grain size Aggregation
26
What characteristics determine the vegetation in any area?
``` Soil composition Grain size Aggregation pH mineral composition topography ```
27
In the aquatic environment the _____ characteristics often determine the type of _____ animals that can thrive there
sediment; | benthic
28
What is homeostasis?
Regulatory Process; | Constancy of an organism's internal environment
29
What are the various responses an organism may have to abiotic factors?
Regulate Conform Migrate Suspend
30
__________________ are capable of thermoregulation and osmoregulation.
All birds and mammals | Few lower vertebrate & invertebrates
31
Humans maintain a constant body temperature of _____
37°C
32
Do plants thermoregulate?
No
33
Do 99% of animals and almost all plants conform or regulate?
Conform
34
What is ambient temperature?
External temperature
35
In aquatic animals, the osmotic concentration of the body fluids change with _______________
ambient air, water osmotic concentration
36
Thermoregulation is energetically inexpensive. T or F?
False, it is expensive
37
Why do small birds and shrews conform to ambient temperature?
Thermoregulation is energetically expensive. Smaller animals => larger surface area => lose body heat very fast => much more energy required to regulate
38
Why are small animals rarely found in polar regions?
Thermoregulation is energetically expensive. Smaller animals => larger surface area => lose body heat very fast => much more energy required to regulate
39
What options do organisms have if stressful external conditions are localised or only temporary?
Migrate or Suspend
40
________ in Rajasthan hosts thousands of migratory birds coming from Siberia every winter
Keolado National Park (Bharatpur)
41
Which plants/animals suspend?
Bears - hibernation Snails and fish - aestivation Zooplankton - diapause Seeds - dormancy (reduced metabolic activity)
42
Why do snails and fish go into aestivation?
To avoid summer-related problems - heat and dessication
43
What is adaptation?
Any morphological, physiological, behavioural attribute of the organism that enables survival and reproduction in its habitat
44
Adaptations can be genetically fixed after a long period of time. T or F?
True
45
Describe adaptation in a kangaroo rat
internal fat oxidation (water is by product); | concentrate its urine
46
Describe adaptation in desert plants
sunken stomata arranged in deep pits special photosynthetic pathway (CAM) => stomata closed during day Opuntia - no leaves, only spines; photosynthesis => flattened stem
47
What is the Allen's Rule?
Mammals - colder climate - shorter ears and limbs - minimal heat loss
48
Describe adaptation in polar mammals
seals of fat (blubber) below skin - insulator
49
How does the human body adapt to altitude sickness?
increasing RBC production, decreasing binding affinity of hemoglobin, increasing breathing rate
50
Human body adaptation to high altitudes is what kind of adaptation?
Physiological
51
Desert lizard adaptation to high temperatures is what kind of adaptation?
Behavioral, bask in sun vs. moving to shade
52
A group of individuals resulting from asexual reproduction is also considered a population in ecological studies. T or F?
True
53
Natural selection operates at the individual or population level to evolve desired traits?
Population level
54
What are attributes of a population?
Death rate Birth rate Sex ratio Age distribution (pyramid)
55
What is population density?
Population size, N | measured in numbers, percent cover or biomass OR relatively (e.g. number of fish caught per trap)
56
Four basic processes that affect population density?
Natality and immigration => increase | Mortality and emigration => decrease
57
What is N at t+1 ?
Nt + [(B + I) - (D + E)]
58
What is relative importance of 4 processes that affect population density?
in normal conditions, B + D matter more in case of new habitat, I may matter more
59
What is the equation for exponential population growth?
dN/dt = (b - d) x N b - d = r = intrinsic rate of natural increase OR, integral form: Nt = N0 * e^rt
60
What is another name for exponential growth?
Geometric growth
61
What is the shape of curve in geometric growth?
J - shape
62
What is logistic growth?
Population growing in habitat with limited resources Lag phase => acceleration => deceleration => asymptote Verhulst-Pearl Logistic Growth
63
What kind of curve for logistic growth?
Sigmoid curve
64
What is "K" in logistic growth?
Nature's carrying capacity - maximum possible number that resources in habitat can support
65
Equation for logistic growth?
dN/dt = rN (K - N / K)
66
What is Darwinian fitness?
Reproductive fitness, "r" value
67
What are organisms that breed only once in a lifetime?
Pacific salmon fish, bamboo
68
What are some organisms that produce large number of small-sized offspring?
Oysters, pelagic fish
69
There is no natural habitat on earth that is inhabited by just one species. T or F?
True
70
What are the different inter-species population interactions?
Mutualism - both gain Competition - both lose Predation - one gains, one loses Parasitism - one gains, one loses Commensalism - one gains, no effect on other Amensalism - one loses, no effect on other
71
In competition, one species loses and the other wins. T or F?
False, both lose
72
In which types of species interaction do the species live close together?
Predation Parasitism Commensalism
73
What important roles do predators play?
1. Keeping prey populations under control | 2. Reducing competition among competing prey => species diversity maintained
74
What defenses have prey animal species evolved?
1. Camouflage 2. Poisonous 3. Distastefulness (Monarch butterfly)
75
What defenses have prey plant species evolved?
1. Thorns (Acacia, Cactus) 2. Chemicals that make animals sick 3. Poison
76
How does the weed Calotropis defend against herbivores?
Produces highly poisonous cardia glycosides
77
Totally unrelated species can also compete for the same resources. T or F?
True
78
What is interference competition?
Feeding efficiency of one species reduced due to interfering presence of other species
79
Define competition
Fitness of one species ( 'r' ) is significantly lower in presence of another species
80
Carnivores are more adversely affected by competition than herbivores and plants. T or F?
False, other way around
81
What is the 'Competitive Exclusion Principle?
Gause; 2 closely related species competing for same resources cannot co-exist indefinitely; competitively inferior will be eventually eliminated
82
The Competitive Exclusion Principle always holds true?
No, only if resources are limiting; | Also species may evolve to co-exist e.g. resource partitioning
83
What is resource partitioning?
If 2 species compete for same resource, they could avoid competition by choosing different feeding times or patterns (e.g. five closely related species of warblers on same tree)
84
Parasites are often host-specific and both parasite and hosts tend to co-evolve. T or F?
True
85
What are some evolved characteristics of parasites?
1. Loss of unnecessary sense organs 2. Adhesive organs / suckers 3. Loss of digestive system 4. High reproductive capacity
86
Life cycles of parasites are complex, how?
Usually involve one or 2 intermediate hosts or vectors
87
What does lifecycle of human liver fluke depend on?
Depends on snail and fish
88
Ectoparasites vs endoparasites?
Ecto - feed on external surface of host e.g. lice, ticks (dogs), copepods (marine fish), Cuscuta plant (other plants) Endo - live inside host
89
Female mosquito is a parasite. T or F?
False, vector. Plasmodium is the parasite
90
Ectoparasite lifecycles are more complex. T or F?
False, endo because they're inside the body => extreme specialization
91
What is brood parasitism?
parasitic bird lays eggs in host nest
92
Examples of commensalism?
Orchid (epiphyte) growing on mango plant barnacles on back of whale cattle egret + grazing cattle (flesh out insects) Sea anemone (stinging tentacles) + clown fish
93
Examples of mutualism?
Lichens - fungus and photosynthesizing algae/cyanobacteria Mycorrhizae - fungi and roots of higher plants Pollinators and plants
94
How does a fig tree exemplify mutualism?
pollinator - wasp, every fig species is specific to a 'partner' wasp species Female wasp uses fruit for nourishment + to lay eggs (oviposition)
95
How does the Mediterranean orchid exemplify mutualism?
Sexual deceit, one flower petal resembles female bee | male bee pseudocopulates
96
Only regulators are capable of homeostatis. T or F?
True
97
Define population
Group of individuals same species sharing / competing for resources defined geographical area
98
When resources become limiting growth pattern turns _________
Logistic
99
Population growth is limited by __________
K - carrying capacity of the environment
100
________ is an important process through which trophic energy transfer is facilitated
Predation
101
Why do snails and fish go into aestivation?
To avoid summer-related problems - heat and dessication

Biology (NCERT) - Class XII (18 decks)

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