FURTHER PHYLOGENETIC CONSIDERATIONS IN AMPHIBIANS There is a problem in amphibian phylogeny. This problem is the relationship among the three orders of modern amphibians. There are two hypotheses about the…
AMPHIBIANS IN PERIL Frogs and salandam are disappearing rapidly. We do not know the exact reasons of their disappearance. Some reasons are: 1. Local factors: Some local factors influence the…
EVOLUTIONARY PRESSURES IN AMPHIBIANS The lives of the most amphibians is divided into freshwater and land. Thus they show adaptations to both environments. The amphibians are supported by the buoyant…
SURVEY OF AMPHIBIANS Amphibians occur on all continents except Antarctica. There are three orders of amphibians: Caudata, (salamanders), Anura, ( frogs and toads) and Gymnophiona (caecilians). ORDER CAUDATA (cauda, tail…
AMPHIBIANS EVOLUTIONARY PERSPECTIVE (amphibia, living a double life) Class Amphibia includes frogs. roads, salamanders and caecilians. Class name shows that amphibians move between water and land. They spend one stage…
OBJECTIVES OF THE FISHES Multiple Choice Questions MCQs 1. Adaptive radiation in fishes started about number of million years ago: (a) 1200 (b) 500 (c) 1000 (d) 1500 2. Bony…
SUBJECTIVE QUESTIONS OF THE FISHES Describe evolutionary perspective of fishes. Describe phylogenetic relationships of fishes. Discuss whether evolution of fishes takes place in marine or fresh water environment. Give characters…
DEFINITIONS AND KEY POINTS FOR OBJECTIVES OF THE FISHES TERMS DEFINITIONS Ostracoderms bony armor fishes called ostracoderms Agna bans Thejawless fishes are called agnathans Aestivation Aestivation is a dormant state…
FURTHER PHYLOGENETIC CONSIDERATIONS IN FISHES Two important series of evolutionary events occurred during the evolution of the Osteichthves: 1. Evolution of teleosts One of these was an evolutionary explosion of…
EVOLUTIONARY PRESSURES The aquatic environments have physical characteristics. These characteristics are important selective forces for aquatic animals. Fishes have following adaptive characteristics: LOCOMOTION Water is dense. It makes movement through…
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