Epiphytes that are growing on a mango branch is an example of which of the following?
A.
Predation
B.
Amensalism
C.
Commensalism
D.
Mutualism
Correct Answer: C
Explanation:
Commensalism is the type of interaction in which one-species benefits and another is neither harmed nor benefited. An orchid growing as an epiphyte on a mango branch is an example of commensalism.
Which one of the following equations represents the Verhulst-Pearl Logistic Growth of population?
A.
$\frac{d N}{d t}=r N\left(\frac{N-K}{N}\right)$
B.
$\frac{d N}{d t}=N\left(\frac{r-K}{K}\right)$
C.
$\frac{d N}{d t}=r\left(\frac{K-N}{K}\right)$
D.
$\frac{d N}{d t}=r N\left(\frac{K-N}{K}\right)$
Correct Answer: D
Explanation:
Logistic growth is captured by the Verhulst-Pearl logistic growth equation, represented as:
$ \frac{d N}{d t} = r N \left( \frac{K-N}{K} \right) $
In this equation:
$ N $ is the population size,
$ r $ is the intrinsic growth rate,
$ K $ is the carrying capacity,
$\frac{d N}{d t}$ indicates the rate of change of the population over time.
This model describes how population growth slows as it approaches the carrying capacity, providing a more realistic scenario than exponential growth models.
When will the population density increase, under special conditions?
When the number of :
A.
Deaths exceeds number of births and also number of emigrants equals number of immigrants.
B.
Births plus number of immigrants equals number of deaths plus number of emigrants.
C.
Births plus number of emigrants is more than the number of deaths plus number of immigrants.
D.
Births plus number of immigrants is more than the sum of number of deaths and number of emigrants.
Correct Answer: D
Explanation:
(N) is the population density at time t, then its density at time t + 1 is
$\mathrm{N_{t+1}=N_t+[(B+I)-(D+E)]}$
Population density will increase if the number of births plus the number of immigrants (B + I) is more
than the number of deaths plus the number of emigrants (D + E).
Chose the correct answer from the options given below:
A.
A-III, B-II, C-I, D-IV
B.
A-IV, B-I, C-II, D-III
C.
A-II, B-III, C-I, D-IV
D.
A-II, B-III, C-IV, D-I
Correct Answer: D
Explanation:
(1) In predation one species is benefitted ‘+’ while the other is detrimental ‘–’. Pisaster is an important predator in the rocky intertidal communities of the American pacific coast.
(2) In many species of fig trees, there is tight one-to-one relationship with the pollinator species of wasp.
It means that a given fig species can be pollinated only by its ‘partner’ wasp species and no other
species is an example of mutualism.
(3) Plasmodium is an endoparasite in humans that causes malaria.
(4) The Mediterranean orchid Ophrys employs ‘sexual deceit’ to get pollination done by a species of bee.
Migratory flamingoes and resident fish in South American lakes
(I)
Interference competition
(B)
Abingdon tortoise became extinct after introduction of goats in their habitat
(II)
Competitive release
(C)
Chathamalus expands its distributional range in the absence of Balanus
(III)
Resource Partitioning
(D)
Five closely related species of Warblers feeding in different locations on same tree
(IV)
Interspecific competition
Choose the correct answer from the options given below:
A.
A-I, B-IV, C-III, D-II
B.
A-IV, B-I, C-II, D-III
C.
A-III, B-1, C-II, D-IV
D.
A-II, B-IV, C-III, D-I
Correct Answer: B
Explanation:
To correctly match List I with List II, let's understand the types of ecological interactions mentioned:
(A) Migratory flamingoes and resident fish in South American lakes would involve interaction for resources like food, which can be classified as interspecific competition (IV).
(B) Abingdon tortoise became extinct after introduction of goats in their habitat indicates that the introduction of goats led to the extinction due to competition for resources, categorizing it as interference competition (I).
(C) Chathamalus expands its distributional range in the absence of Balanus shows that one species expands its range when the other is absent, which is known as competitive release (II).
(D) Five closely related species of Warblers feeding in different locations on same tree is an example of resource partitioning (III), where species divide a niche to avoid competition.
What do 'a' and 'b' represent in the following population growth curve?
A.
‘a’ represents exponential growth when responses are not limiting the growth; and ‘b’ represents logistic
growth when responses are limiting the growth.
B.
‘a’ represents logistic growth when responses are not limiting the growth; ‘b’ represents exponential
growth when responses are limiting the growth.
C.
‘a’ represents carrying capacity and ‘b’ shows logistic growth when responses are limiting the growth.
D.
‘a’ represents exponential growth when responses are not limiting the growth and ‘b’ shows carrying
capacity.
Correct Answer: A
Explanation:
The given graph represents the population growth curve where ‘a’ represents exponential growth when
responses are not limiting the growth which forms a J-shaped curve and ‘b’ represents logistic growth
when responses are limiting the growth which forms an S-shaped curve.
The equation of Verhulst-Pearl logistic growth is $\frac{\mathrm{dN}}{\mathrm{dt}}=\mathrm{rN}\left[\frac{\mathrm{K}-\mathrm{N}}{\mathrm{K}}\right]$.
From this equation, $\mathrm{K}$ indicates:
A.
Intrinsic rate of natural increase
B.
Biotic potential
C.
Carrying capacity
D.
Population density
Correct Answer: C
Explanation:
The Verhulst-Pearl logistic growth equation you've presented is a fundamental model used to describe how populations grow under limited resource conditions. This model is sensitive to both the variables and coefficients it incorporates:
$\mathrm{N}$ represents the population size at time $t$.
$\mathrm{r}$ is the intrinsic rate of natural increase, indicating the rate at which the population grows per individual when resources are not limiting.
$\mathrm{K}$ represents the carrying capacity of the environment.
In the context of this equation:
The term $\left[\frac{\mathrm{K} - \mathrm{N}}{\mathrm{K}}\right]$ is a fraction that reduces the effective growth rate as the population size $\mathrm{N}$ approaches the carrying capacity $\mathrm{K}$. This term essentially represents the remaining proportion of resources available as the population grows larger.
Based on this understanding:
Option A: "Intrinsic rate of natural increase" – Incorrect, this is represented by $\mathrm{r}$ in the equation.
Option B: "Biotic potential" – Incorrect, biotic potential generally refers to the maximum reproductive capacity of an organism under optimal conditions, often considered similar to $\mathrm{r}$ but not specifically the same as $\mathrm{K}$.
Option C: "Carrying capacity" – Correct, as $\mathrm{K}$ in the equation is specifically describing the carrying capacity, which is the maximum population size that the environment can sustain indefinitely given the food, habitat, water, and other necessities available in the environment.
Option D: "Population density" – Incorrect, while $\mathrm{N}$ relates directly to population density at any time, $\mathrm{K}$ is about the upper limit of that density sustainable by the environment.
Therefore, Option C is the correct answer. The variable $\mathrm{K}$ in the Verhulst-Pearl logistic growth equation indeed stands for the carrying capacity.
Which one of the following factors will not affect the Hardy-Weinberg equilibrium?
A.
Genetic recombination
B.
Genetic drift
C.
Gene migration
D.
Constant gene pool
Correct Answer: D
Explanation:
The Hardy-Weinberg equilibrium is a principle that predicts how gene frequencies in a population's gene pool will remain constant over time, assuming certain conditions are met. These conditions include no mutation, random mating, no gene flow, infinite population size, and no selection. If any of these conditions are violated, then the Hardy-Weinberg equilibrium can be disrupted.
Option A: Genetic recombination
Genetic recombination refers to the process by which genetic material is rearranged or exchanged between different chromosomes or between different regions within the same chromosome. It can introduce new gene combinations into a population but does not itself change allele frequencies unless it is associated with differential survival or reproduction. Thus, genetic recombination alone does not disrupt Hardy-Weinberg equilibrium.
Option B: Genetic drift
Genetic drift is a stochastic effect that occurs due to the random sampling of alleles when gametes are formed, and it can greatly influence the allele frequencies in small populations. It can cause random changes in allele frequencies over time, thereby affecting the Hardy-Weinberg equilibrium.
Option C: Gene migration
Gene migration or gene flow involves the transfer of alleles from one population to another. When individuals move between populations, they can introduce new alleles to the gene pool, or change the relative frequencies of existing alleles, both of which disturb the Hardy-Weinberg equilibrium.
Option D: Constant gene pool
A constant gene pool implies no change in allele frequencies over time, which is in line with the Hardy-Weinberg principle. Therefore, by definition, this factor does not affect or disrupt the Hardy-Weinberg equilibrium.
Based on these explanations, Option D: Constant gene pool is the factor that will not affect the Hardy-Weinberg equilibrium as it represents the ideal condition where allele frequencies remain consistent, which is central to the Hardy-Weinberg principle.
Statement I: Gause's competitive exclusion principle states that two closely related species competing for different resources cannot exist indefinitely.
Statement II: According to Gause's principle, during competition, the inferior will be eliminated. This may be true if resources are limiting.
In the light of the above statements, choose the correct answer from the options given below :
A.
Both Statement I and Statement II are true.
B.
Both Statement I and Statement II are false.
C.
Statement I is true but Statement II is false.
D.
Statement I is false but Statement II is true.
Correct Answer: D
Explanation:
Let's analyze the two statements given and compare them with Gause's competitive exclusion principle.
Statement I: "Gause's competitive exclusion principle states that two closely related species competing for different resources cannot coexist indefinitely." This statement is incorrect. Gause's principle actually states that two species competing for the same limited resource cannot coexist indefinitely. If the resources are different, the principle does not necessarily apply because the species are not directly competing against each other for the same needs. Therefore, the correct phrasing should refer to species competing for the same resource.
Statement II: "According to Gause's principle, during competition, the inferior will be eliminated. This may be true if resources are limiting." This statement accurately describes a possible outcome according to Gause's competitive exclusion principle. The principle suggests that in a scenario where two species compete for the same limited resource, one species will often outcompete the other, leading to the decline or possible extinction of the less competitive species.
From the analysis above:
Statement I is false because it incorrectly states that species compete for different resources under Gause's principle.
Statement II is true as it correctly highlights the eventual elimination of one species due to competition over limited resources.
Therefore, the correct answer is:
Option D: Statement I is false but Statement II is true.
Plants offer rewards to animals in the form of pollen and nectar and the animals facilitate the pollination process. This is an example of :
A.
Amensalism
B.
Competition
C.
Commensalism
D.
Mutualism
Correct Answer: D
Explanation:
This is an example of Mutualism. Mutualism is a type of symbiotic relationship in which both organisms involved benefit. In this case, the plant benefits by having its pollen dispersed by the animal, thus facilitating pollination, and the animal benefits by obtaining food in the form of pollen and nectar.
Therefore, the correct answer is Option D : Mutualism.
If there are 250 snails in a pond, and within a year
their number increases to 2500 by reproduction.
What should be their birth rate per snail per year ?
Statement I : Gause’s ‘Competitive Exclusion Principle’ states that two closely related species competing for the same resources cannot co-exist indefinitely and competitively inferior one will be eliminated eventually.
Statement II : In general, carnivores are more adversely affected by competition than herbivores.
In the light of the above statements, choose the correct answer from the options given below:
A.
Both Statement I and Statement II are false.
B.
Statement I is correct Statement II is false.
C.
Statement I is incorrect but Statement II is true.
D.
Both Statement I and Statement II are true.
Correct Answer: B
Explanation:
Gause's 'Competitive Exclusion Principle' states that two closely related species competing for the
same resources cannot co-exist indefinitely and the competitively inferior one will be eliminated
eventually. Thus, statement I is correct.
Statement II is incorrect as in general, herbivores and plants appear to be more adversely affected by
competition than carnivores.
Choose the correct answer from the options given below.
A.
A-I, B-II, C-IV, D-III
B.
A-III, B-IV, C-I, D-II
C.
A-II, B-III, C-I, D-IV
D.
A-I, B-II, C-III, D-IV
Correct Answer: D
Explanation:
- A leopard and a lion in a forest/grassland (A) : These two species are predators that hunt in the same environment and likely compete for the same prey. This is an example of competition (I).
- A cuckoo laying an egg in a crow's nest (B) : The cuckoo is known for laying its eggs in the nests of other birds, such as crows. The crow then raises the cuckoo's young, often at the expense of its own offspring. This is a form of brood parasitism (II).
- Fungi and the root of a higher plant in mycorrhizae (C) : Mycorrhizae are symbiotic relationships between fungi and plant roots, in which the fungi help the plant absorb water and nutrients from the soil, while the plant provides the fungi with carbohydrates. This is an example of mutualism (III).
- A cattle egret and a cattle in a field (D) : Cattle egrets are often seen near cattle, feeding on the insects that the cattle stir up as they move and graze. The egret benefits from this interaction (by getting easy access to food), while the cattle are unaffected. This is an example of commensalism (IV).
The percent individuals of pre-reproductive age is largest followed by reproductive and post reproductive age groups
(D)
Stable age pyramid
(IV)
The percent individuals of pre-reproductive and reproductive age group are same
Choose the correct answer from the options given below:
A.
A-II, B-III, C-I, D-IV
B.
A-II, B-IV, C-I, D-III
C.
A-II, B-IV, C-III, D-I
D.
A-II, B-I, C-III, D-IV
Correct Answer: D
Explanation:
- Logistic growth (A) is a type of population growth that occurs under conditions of limited resources (II).
- Exponential growth (B) is a type of population growth that occurs under conditions of unlimited resources (I).
- An expanding age pyramid (C) represents a population where the percentage of individuals in the pre-reproductive age group is the largest, followed by the reproductive and post-reproductive age groups (III).
- A stable age pyramid (D) represents a population where the percentage of individuals in the pre-reproductive and reproductive age groups are approximately equal (IV).
Which one of the following statements cannot be connected to Predation?
A.
It helps in maintaining species diversity in a community
B.
It might lead to extinction of a species
C.
Both the integrating species are negatively impacted
D.
It is necessitated by nature to maintain the ecological balance
Correct Answer: C
Explanation:
One of the species in predation gains benefit on the expense of the other. Predators help in maintaining species diversity in a community, by reducing the intensity of competition among competing prey species. If a predator is too efficient and overexploits its prey, then the prey might become extinct.
While explaining interspecific interaction of population, (+) sign is assigned for beneficial interaction, ($-$) sign is assigned for detrimental interaction and (0) for neutral interaction. Which of the following interactions can be assigned (+) for one specifies and ($-$) for another specifies involved in the interaction?
A.
Predation
B.
Amensalim
C.
Commensalism
D.
Competition
Correct Answer: A
Explanation:
In predation, one species is benefited where as the other is harmed. It is (+ $-$) type of population interaction.
If '8' Drosophila in a laboratory population of '80' died during a week, the death rate in the population is ___________ individuals per Drosophila per week.
A.
0.1
B.
10
C.
1.0
D.
zero
Correct Answer: A
Explanation:
If 8 Drosophila in a laboratory population of 80 died during a week, the death rate in the population is ${8 \over {80}} = 0.1$ individuals per Drosophila per week.
$\bullet$ Amensalism is an interaction between two organisms of different species in which one species inhibits the growth of other species by secreting certain chemicals. The first species is neither get benefited nor harmed.
$\bullet$ (+) : (0) interaction is observed in commensalism.
$\bullet$ (+) : (+) interaction is observed in mutualism.
$\bullet$ ($-$) : ($-$) interaction is seen in competition.
Secondary metabolites such as nicotine,
strychnine and caffeine are produced by plants
for their
A.
Nutritive value
B.
Growth response
C.
Effect on reproduction
D.
Defence action
Correct Answer: D
Explanation:
A wide variety of chemical substances
that we extract from plants on a commercial
scale (nicotine, caffeine, quinine, strychnine,
opium, etc) are produced by them (plants) as
defences against grazers and browsers.
Which of the following is not an attribute of a
population?
A.
Natality
B.
Sex ratio
C.
Mortality
D.
Species interaction
Correct Answer: D
Explanation:
Natality refers to the number of births
during a given period in the population that
are added to the initial density. Mortality is
the number of deaths in the population during
a given period. Population interaction is the
interaction between different populations. It
refers to the effects that the organisms in a
community have on one another. The sex ratio
is the ratio of males to females in a population.
(i) Symbiotic association or fungi with plant roots
(b) Parasite
(ii) Decomposition of dead organic materials
(c) Lichens
(iii)Living on living plants of animals
(d) Mycorrhiza
(iv) Symbiotic association of algae and fungi
Choose the correct answer from the options given below :
A.
(a)
(b)
(c)
(d)
(i)
(ii)
(iii)
(iv)
B.
(a)
(b)
(c)
(d)
(iii)
(ii)
(i)
(iv)
C.
(a)
(b)
(c)
(d)
(ii)
(i)
(iii)
(iv)
D.
(a)
(b)
(c)
(d)
(ii)
(iii)
(iv)
(i)
Correct Answer: D
Explanation:
A saprophyte is an organism that survives on dead and decaying organisms like fungi and decomposition
bacteria.
A parasite is an organism that survives on living plants and animals.
A lichen is symbiotic association of algae & fungi.
Mycorrhiza is a symbiotic association of fungi and roots of higher plants like pinus
Which one of the following plants shows a
very close relationship with a species of moth,
where none of the two can complete its life
cycle without the other?
A.
Hydrilla
B.
Yucca
C.
Banana
D.
Viola
Correct Answer: B
Explanation:
A very close relationship exists between a
species of moth and Yucca where both species
cannot complete their life cycles with out
each other.
Which one of the following population
interactions is widely used in medical science
for the production of antibiotics?
A.
Commensalism
B.
Mutualism
C.
Parasitism
D.
Amensalism
Correct Answer: D
Explanation:
In amensalism, one species is harmed
whereas the other is unaffected. Antibiosis
also shows this feature where the antibiotics
released by the microbial group (Penicillium)
Has affect on other microbes (such as
Staphylococcus.
pre-reproductive individuals are more than
the reproductive individuals
B.
reproductive individuals are less than the
post-reproductive individuals
C.
reproductive and pre-reproductive
individuals are equal in number
D.
pre-reproductive individuals are less than
the reproductive individuals.
Correct Answer: A
Explanation:
In a population where the number of prereproductive individuals or the younger individual
is larger than the reproductive individuals, the
population will increase.
Presence of plants arranged into well defined vertical layers depending on their height can be seen best in :
A.
Grassland
B.
Tropical Savannah
C.
Temperate Forest
D.
Tropical Rain Forest
Correct Answer: D
Explanation:
The tropical rain forest have five vertical
strata on the basis of plants height i.e., ground
vegetation, shrubs, short canopy trees, tall
canopy trees and tall emergent trees.
Which of the following is correct for r-selected species ?
A.
Small number of progeny with small size
B.
Small number of progeny with large size
C.
Large number of progeny with small size
D.
Large number of progeny with large size
Correct Answer: C
Explanation:
Organisms that are r-selected (rstrategists) able to colonise a habitat rapidly,
utilising the food and other resources before other
organisms are established and begin to compete.
The r-strategists tend to be relatively small
organisms with short life spans (e.g., bacteria) and
often live in temporary or unstable environments;
characteristically their survival depends on their
ability to produce large numbers of offspring rather
than on their ability to compete.
If '+' sign is assigned to beneficial interaction, '–' sign to detrimental and '0' sign to neutral interaction, then the population interaction represented by '+' '–' refers to
A.
parasitism
B.
commensalism
C.
mutualism
D.
amensalism
Correct Answer: A
Explanation:
Parasitism is an association in which one
organism (the parasite) lives on (ectoparasitism) or
in (endoparasitism) the body of another organism
(host), from which it obtains its nutrients. This
association is beneficial for the parasites as they
get continuous supply of nutrients from their host
and are able to rapidly multiply their numbers. But it
is detrimental for the host organism as parasitic
infection leads to various complications and
diseases in the host body may also be fatal to the
host under certain circumstances.
The principle of competitive exclusion was stated by
A.
MacArthur
B.
G. F. Gause
C.
Verhulst & Pearl
D.
C. Darwin
Correct Answer: B
Explanation:
Two or more species with closely similar
niche requirements cannot exist indefinitely in the
same area as sooner or later they come into
competition for possession of it. This is called as
Gause’s competitive exclusion principle, which states
that an ecological niche cannot be simultaneously
and completely occupied by established populations
of more than one species. Two species can live in
same habitat but not in the same niche. More similar
the two niches are, severe the competition is.
It is much easier for a small animals to run uphill than for a large animal, because -
A.
The efficiency of muscles in large animals is less than in the small animals
B.
Smaller animals have a higher metabolic rate
C.
It is easier to carry a small body weight
D.
Small animals have a lower O2 requirement
Correct Answer: B
Explanation:
Basal metabolic rate is the minimum
amount of energy needed to keep the body
functioning. It is inversely proportional to
the size of body, thus smaller animals have a
higher metabolic rate.
When does the growth rate of a population following the logistic model equal zero? The logistic model is given as
dN/dt = rN(1-N/K)
A.
When death rate is greater than birth rate.
B.
When N/K equals zero.
C.
When N/K is exactly one.
D.
When N nears the carrying capacity of the habitat.
Correct Answer: C
Explanation:
In logistic growth model population
growth equation is described as
${{dN} \over {dt}} = rN\left( {1 - {N \over K}} \right)$
N = population density at time t;
r = Intrinsic rate of natural increase;
K = carrying capacity
When N/K = 1; ${1 - {N \over K}}$ = 0
Therefore, ${{dN} \over {dt}} = 0$
Gause's principle of competitive exclusion states that -
A.
Larger organisms exclude smaller ones through competition
B.
More abundant species will exclude the less abundant species through competition
C.
Competition for the same resources excludes species having different food preferences
D.
No two species can occupy the same niche indefinitely for the same limiting resources
Correct Answer: D
Explanation:
Gause’s principle of competitive
exclusion can be restated to say that no two
species can occupy the same niche indefinitely
when resources are limiting. Certainly species
can and do coexist while competing for some
of the same resources. Nevertheless, Gause’s
theory predicts that when two species coexist
on a long-term basis, either resources must not
be limited or their niches will always differ in
one or more features; otherwise, one species
will outcompete the other and the extinction
of the second species will inevitably result, a
process referred to as competitive exclusion.
In which of the following interactions both
partners are adversely affected?
A.
Competition
B.
Predation
C.
Mutualism
D.
Parasitism
Correct Answer: A
Explanation:
Competition is the rivalry between two or
more organisms for obtaining the same resources
such as food, light, water, space, shelter, mate, etc.
Competitors adversely affect each other.
Just as a person moving from Delhi to Shimla to escape the heat for the duration of hot
summer, thousands of migratory birds from Siberia and other extremely cold northern regions
move to:
A.
Keolado National Park
B.
Meghalaya
C.
Corbett National Park
D.
Western Ghat
Correct Answer: A
Explanation:
The Keoladeo National Park is a famous
avifauna sanctuary in India that plays host
to thousands of birds especially during the
summer season. It is formerly known as
the Bharatpur Bird Sanctuary in Bharatpur,
Rajasthan. October to February is the best
time, for the migratory birds are there as well
as the residents. In August local birds start
their nest building and rear their young for
the next few months. October/November is
when the migrants arrive. Most stay till March
including the Siberian Crane.
Which one of the following is not a parasitic
adaptation ?
A.
Loss of digestive organs
B.
Loss of unnecessary sense organs
C.
Development of adhesive organs
D.
Loss of reproductive capacity
Correct Answer: D
Explanation:
In Parasitism, one species (parasite) is
benefitted and the other (host) is harmed.
Parasites have very high reproduction
capacity. The life cycles of parasites are often
complex, involving one or two intermediate
hosts or vectors to facilitate parasitisation of
its primary host.
Age pyramid is a graphic representation
of abundance of individuals of different age groups
with pre-reproductive individuals at the base,
reproductive individuals in the middle and postreproductive individuals at the top. Triangular age
pyramid has high proportion of pre-reproductive
individuals, moderate number of reproductive
individuals and fewer post-reproductive individuals.
It represents young or rapidly growing population.
In bell-shaped age pyramid, the number of prereproductive and reproductive individuals is almost
equal. Post -reproductive individuals are
comparatively fewer. It represents stable or
stationary population where growth rate is nearly
zero. In urn-shaped age pyramid, the number of
reproductive individuals is higher than the number
of pre-reproductive individuals. It represents
declining or diminishing population.
A biologist studied the population of rats in a barn, He found that the average natality was 250, average
mortality 240, immigration 20 and emigration 30. The net increase in population is :
A.
15
B.
05
C.
10
D.
zero
Correct Answer: D
Explanation:
Net increase in population :
(Natality + Immigration) – (Mortality
+ Emigration)
(250 + 20) – (240 + 30) = 270 – 270 = 0
Besides paddy fields, cyanobacteria are also found inside vegetative part of :
A.
Cycus
B.
Psilotum
C.
Pinus
D.
Equisetum
Correct Answer: A
Explanation:
Coralloid roots of Cycas have symbiotic
association with blue-green algae like Nostoc and
Anabaena. Coralloid roots are irregular, negatively
geotropic, dichotomously branched coral like roots
which do not possess root hairs and root caps.
