ZOO503 Final Term Solved Papers

Q1. What is Study of trace fossil is called? 2

The study of trace fossils, often called ichnology (from the Greek ichnos, a trace).

Q2. What is meant by Biogeography? 2

Biogeography is the study of the distribution of species and ecosystems in geographic space and through geological time.

Q3. Redundant species hypothesis? 3

According to the redundant species hypothesis, the removal of certain species from an ecosystem would have little or no effect on the functioning of that ecosystem. Here, the function of an ecosystem could refer to its overall productivity, its rate of nutrient cycling or its general self‐ sustainability.

Q4. What are characteristic features of Pterosaurs? 3

The pterosaurs were proficient flapping flyers, with a lightweight body, narrow hatchet-shaped skull and a long narrow wing supported on a spectacularly elongated fourth finger of the hand. Pterosaurs were covered with hair, and were almost certainly endothermic. Most pterosaurs fed on fishes caught in coastal seas, but others were insectivorous.

Q5. Functions of Geographic Information System.

Modern biogeography often employs the use of Geographic Information Systems (GIS), to understand the factors affecting organism distribution, and to predict future trends in organism distribution. Often mathematical models and GIS are employed to solve ecological problems that have a spatial aspect to them.

Q6. History of old world tropical mammal fauna of Africa 5

Africa contains the best known and most distinctive of the Old World tropical mammal fauna. Molecular studies of the interrelationships of the different orders of placentals suggest that the common ancestor of a group of African placentals entered the continent in the Late Cretaceous. This group is made up of the elephants, hyracoids (conies), aquatic sirenians (sea cows), elephant shrews, aardvarks, Cape golden moles, insectivorous tenrecs and extinct embrithopods; they have been placed together in a super order, Afrotheria, that is endemic to Africa. The early horse Hipparion, which had evolved in North America, appeared in both Eurasia and Africa, while rhinoceros, hyenas and sabre‐ toothed cats dispersed from Africa to Eurasia. The elephants originated in Africa in the Eocene, migrated into Eurasia in the Early Miocene and migrated back later in the Miocene. The ancestors of the mammoths and modern Asian elephant probably evolved in Africa 4 to 5 mya and migrated back into Eurasia 2 million years later.

Q7. What are three types of radiated amniotes 5

Amniotes radiated during the Late Carboniferous, giving rise to three main clades. These are distinguished by the pattern of openings in the side of the skull, especially the temporal openings behind the eye socket. These three skull patterns diagnose the key clades among amniotes which are i. The anapsid (“no arch”) is the primitive state skull pattern, since there are no temporal openings. The Anapsida include various early forms such as Hylonomus, as well as some Permian and Triassic reptiles, and the turtles. The two other skull patterns seen in amniotes are

ii. The synapsid (“same arch”), where there is a lower temporal opening. The Synapsida include the “mammal-like reptiles” and the mammals.

iii. The diapsid (“two arch”) pattern, where there are two temporal openings. The Diapsida includes a number of early groups, as well as the lizards and snakes and the crocodiles, pterosaurs, dinosaurs and birds.

Q8. Work of Leon Croizat in field of Biogeography.

He amassed a vast array of distributional data, representing each biogeographical pattern as a line, or track, connecting its known areas of distribution. Croizat studied the distribution patterns of many unrelated taxa, and for each he drew lines or ‘tracks’ on the map linking the areas in which they are found. In many cases, these lines were similar enough in position to be combined as ‘generalized tracks’, shown here. He found that the tracks of many taxa, belonging to a wide variety of organisms, could be combined to form a generalized track that connected different regions of the world

Q9. Write a note on geographical history of New Caledonia

New Caledonia

Geological studies show that New Caledonia is the smallest (about 1600 km2) surviving fragment of Gondwana, having rifted away from Australia in the Late Cretaceous 80–65 mya and reaching its present position 1500 km east of it 50 mya. It is a hotspot for diversity: 77% of its flowering plant species are endemic to the island, as are 98% of the species of the flowering plant family Sapotaceae. In view of the large amount of research that shows the frequency of long‐ distance dispersal in

such scenarios, most biogeographers today believe that this was the mechanism of arrival of the ancestors of the New Caledonian taxa. Geological studies show that the island was submerged for long periods in the Paleocene– Eocene, so that the island was not available for colonization until about 37 mya. The New Caledonian species must therefore have diverged from their ancestors after this date. Panbiogeographers, however, reject long‐ distance dispersal. They therefore have to theorize

that the Cretaceous ancestors of the present biota were widespread across the Pacific islands, including on supposedly formerly exposed large plateaux such as the Ontong Java plateau.

Biogeographers in Sweden and France have investigated the history of the New Caledonian species of the angiosperm family Sapotaceae. They found that these resulted from nine separate colonizations of the island between 33 and 4.2 mya, dates that are about 40 million years after the rifting of New Caledonia from Australia. New Guinea and Australia were the most important sources of the arrivals, those from Pacific islands arriving only more recently, 27–24 mya. These results are clearly totally incompatible with the panbiogeographers’ theories.

Q10. What are two key defining characters of Jawless fishes? 2

Two key defining characters: The head and neural crest tissues.

The neural crest appears in the early embryo as a strip of cells lying just below the outer skin, the ectoderm, of the embryo, above the line of where the backbone will develop.

Q11. Oldest clear evidence for bipedalism

The oldest clear evidence for bipedalism was the find of some human tracks in volcanic ash from Tanzania, dated at 3.75 Ma. The oldest substantial skeletons, of Praeanthropus afarensis, come from rocks dated at about 3.2 Ma and also show clear anatomic evidence for advanced bipedalism, but still an ape-sized brain.

Q12. What is Kleptoparasitisim with example? 5

Kleptoparasitism (literally, parasitism by theft) is a form of feeding in which one animal takes prey or other food from another that has caught, collected, or otherwise prepared the food, including stored food (as in the case of cuckoo bees, which lay their eggs on the pollen masses

wasps). The term is also used to describe the stealing of nest material or other inanimate objects from one animal by another. One very widespread duck in both continents is the gadwall. It feeds mainly on submerged vegetation, which is most abundant in nutrient‐ rich (eutrophic) waters. It cannot dive, so it feeds by upending, and this generally restricts it to the shallow parts of a lake, where it may encounter some competition from other water birds, such as the mallard. Coots (both Eurasian coot and the American coot dive for their food and bring vegetable matter to the surface from greater depths. The coots are messy eaters, and it is not difficult for gadwall to move in and collect some of the loot. This behavior is called kleptoparasitism, and it is an effective way of widening the niche of the gadwall.