1. Where and how did we preserve skeletons of animals, dry specimens, etc.?
A: The skeletons, dry specimens are preserved in museums. Animal specimens are preserved in jars filled with preservative solutions like formaldehyde. Insects are preserved in insect boxes after pinning on sheets. Large animal which are not suitable specimen jar storage are preserved in 'stuffed' forms.
2. Differentiate between Protostomia and Deuterostomia.
A: The animals in which mouth appears as first opening (blastopore develops into mouth) are protostomes. They are kept under division
Protostomia. In deuterstomes mouth forms as secondary opening in the development. i.e., from blastopore or closer to blastopore anus
forms. These animals are included in the division Deuterostomia.
3. Nematode is a protostomian but not a eucoelomate. Justify the statement.
A: In nematodes, like other protostomes, mouth forms as first opening from blastopore. But their body cavity is not lined by
peritoneal layers i.e, not true coelom (eucoelom).
4. What is ecological diversity? Mention the different types of ecological diversities.
A: Variation of life at various levels of biological organization is called biodiversity. Diversity at the ecosystem level is called ecological diversity. e.g.: ecological diversity in India - deserts, rain forests, mangroves, coral reefs, wetlands.
5. Define species richness.
A: Number of species per unit area is called species richness. The more the number of species in an area the more is the species
richness. German naturalist and geographer Alexander von Humboldt observed that within a region, species richness increased with increasing explored area, but only up to a limit.
6. Mention any two products of medicinal importance obtained from
A: Medicinally important products obtained from nature are anti
cancer drugs - Vinblastin from Vinca rosea, Digitalin from fox
glove plant is used to treat cardiac problems.
7. Invasion of an Alien species leads to extinction of native species. Justify this with two examples.
A: When alien species are introduced into a habitat, they turn invasive and establish themselves at the cost of indigenous species. e.g. Nile perch introduced into Lake Victoria, in East Africa led to the extinction of 200 species of cichlid fish in the lake.
e.g.: Illegal introduction of exotic African catfish, Clarius gariepinus, for aquaculture purposes is posing a threat to the indigenous cat fishes.
8. List out any four sacred groves in India.
A: A grove of trees of special religious importance to a particular culture is called sacred grove. Some sacred groves in India are
1) Khasi and Jaintla Hills (Meghalaya),
2) Aravalli Hills (Rajasthan and Gujarat),
3) Western Ghat region (Karnataka, Maharashtra),
4) Sarguja, Bastar (Chattisgarh),
9. Explain the hierarchy of classification.
A: Systematics is the branch of science that deals with the vast diversity life. It also reveals the trends and evolutionary relationships of different groups of the organisms. A key part of systematics is taxonomy. Taxonomic hierarchy includes seven obligate categories namely kingdom, phylum, class, order, family, genus and species, and other intermediate categories such as subkingdom, grade, division, subdivision, subphylum, superclass, superorder, suborder, superfamily, subfamily, subspecies, etc.
10. What are the reasons for greater biodiversity in the tropics?
A: Tropics accommodate more species than temperate or polar regions. Species diversity is more in tropics because of 1) they are not disturbed and had a long evolutionary time, 2) constant climate 3) abundance of natural resources.
Tropical latitudes have remained relatively undisturbed for millions of years and thus had a long evolutionary time. A long duration was
available in this region for speciation, it led to the species diversification.
Tropical climates are relatively more constant and predictable than that of the temperate regions. Constant environment promotes niche
specialization and this leads to greater species diversity.
Solar energy, resources like water etc., are available in abundance in tropical region. It contributed to higher productivity in terms of
food production, leading to greater diversity.
11. What is the 'evil quartet?
A: Evil Quartet (four horsemen of ecological apocalypse) speaks about four factors that impact on the environment that lead to loss
of biodiversity. Those four factors are 1) Habitat destruction, 2) Pollution, 3) Invasion of exotic species, and 4) Over exploitation.
12. What is the importance of slope of regression in species - area relationship?
A: One of the most important properties of a straight line is in how it angles away from the horizontal. This concept is reflected in
something called the "slope" of the line. Slope of regression is indicated by 'Z'. It stands for increase or decrease of species per unit area. Ecologists have discovered that the value of 'Z' lies in the range of 0.1 to 0.2, regardless of taxonomic group or the area. But if we analyze the species-area relationships among very large areas like the entire continents ' Z ' values are in 0.6 to 1.2 and the slope of the line to be much steeper. In tropical forests of different continents the slope of line for fruit eating birds is 1.15.