A few males and females of a species were introduced to a new island. Their population was monitored over several generations and followed a pattern shown in the figure:
Which of the characteristics of the species does NOT explain the pattern?
Skewed sex ratio (more females than males)
Large litter size
Delayed sexual maturity
Effects of intra-uterine development on fecundity
A.
Skewed sex ratio (more females than males)
Skewed sex ratio does not explain the above given pattern.
Three islands have identical habitat characteristics. On first island rodent species A is present at a density 325/ km2. Second island has only species B at a density of 179/km2. On the third island, both A and B co-exist with densities 297/km2 and 150/km2, respectively. Which of the following can be inferred from this?
The two species do not compete with each other.
The intra-species competition is more intense than inter-species competition.
The inter-species competition is more intense than intra-species competition.
The inter and intra species competition are of the same intensity.
Environmental conditions can influence the accumulation of species in successional communities. Curved representing changes in forest species over time are given in the figure below. Which of the following keys is correct for the curves?
A = xeric; B = mesic; C = intermediate
A= intermediate; B = xeric; C = mesic
A = intermediate; B = mesic; C = xeric
A = mesic; B = intermediate; C = xeric
A plant with blue-coloured flowers was observed to attract a large number of pollinators. However, these flowers were not producing any nectar. Which of the following canbe a logical explanation to be observation?
There could be another species in the vicinity that has blue flowers and is rich in nectar.
There is no other species with blue flowers in the vicinity so pollinators are compelled to visit this species.
Pollinators may not have blue-colour vision.
Pollinatory may be able to see only blue colour
India has currently 17 biosphere reserves representing different ecosystem. these conservation areas significantly differ from the conventional protected areas of the country. Identify the correct combination of attributes (A to G) that best explains the concept of biosphere reserve.
(A) Conservation
(B) Education
(C) Human habitation allowed
(D) Human habitation not allowed
(E) Strong legal back-up
(F) No supporting act
(G) Research
(A), (B), (C), (F), (G)
(A), (B), (D), (F), (G)
(A), (B), (C), (E), (G)
(A), (D), (E), (G)
Plasmids are self-replicating small circular DNA elements in bacterial cells that can be said to have stable symbiotic existence with the host cell. They often carry genes useful to the host. Which of the following is a potential threat to the evolution and stability of the symbiotic coexistence?
'Copy-up' mutations that increase the rate of plasmid replication per host cell cycle.
Reversible integration of plasmid DNA into the host DNA.
Transfer of plasmids to new cells by conjugation.
Spontaneous curing of plasmids in a small proportion of host cells.
In an experiment that has continued for more than 50 years, corn has been propagated by breeding only from plants with the highest amount of oil in the seeds. The average oil content is now much greater than any of the plants in the original population.
The following hypotheses were proposed as explanations for this observation.
(A) Mutations occurred increased the oil content in seeds.
(B) Plants with high oil content were stimulated to produce offspring with more oil in their seeds.
(C) The breeding led to increased frequency of alleles at multiple loci, so that new combinations of genes for even higher oil content were formed.
Which of the following represents a combination of correct statements?
(A) and (B) only
(A) and (C) only
(B) and (C) only
(A), (B), and (C)
Following are the niche characteristics of the constituent species and resource partitioning pattern in different ecosystems. Which of these would lead to competitive exclusion of species?
Knox genes code transcriptional factors important for the regulation of indeterminate growth in plants shoots. These genes also regulate patterns of development of plant organs such as leaves and flowers. The figure represents a phylogenetic tree of the multigene family in some land plants. The circles represent genes that act to maintain shoot apical meristem (equivalent to stem cells). Orthologues are genes that duplicate due to speciation and paralogues are genes that duplicate within a species.
From the figure, the following inferences were made-
(A) Multiple gene duplication occurred in vascular plants.
(B) Gene duplications may have enabled shoot diversification in vascular plants.
(C) Shoot apical meristems are regulated by orthologous genes in vascular plants.
(D) Shoot apical meristems are regulated by paralogous genes in vascular plants.
Which of the following represents a combination of correct inferences?
(A), (B) and (D)
(A), (B) and (C)
(B) and (C) only
(B) and (D) only
Complex eukaryotic cells may have evolved from simpler prokaryotic cells because the complexity of organization increases the
growth rate
efficiency of energy utilization
tolerance to starvation
ability to attain larger size
