Biodiversity
Subject: AACB3214 Biodiversity and Ecology
Experiment 7
Title: Study of Deuterostomes
Aim:
1. To observe the external features of deuterostomes.
2. To study the characteristics of deuterostomes.
Materials:
1. Sea urchin
2. Amphioxus
3. Dogfish
4. Caecilian
5. Lizard
6. Microscope
Methods:
1. The specimen of sea urchin, amphioxus, dogfish, caecilian and lizard were observed.
2. The external features of specimens observed were drawn.
Discussion:
The Deuterostomia comprise one of the major groups within the animal kingdom, and it is probably the most familiar to you, since you are a deuterostome! Most of the deuterostomes belong to one of two groups that include the majority of its members -- the echinoderms (the spiny skinned starfish, sea urchins, and their relatives) and the chordates (which include fish and other vertebrates). It may be surprising to some that chorates and echinoderms are related -- most people do not feel close kinship with sea urchins and sea cucumbers -- but both groups share a number of important morphological and developmental features.
In turn, the deuterostomes belong to a larger group within the Animalia called the Bilateria, because they are bilaterally symmetrical with a left and a right side to their bodies. Obviously this is not true for adult echinoderms like starfish, and you may wonder what radially symmetric critters are doing in this group. The answer lies in the development of the embryo. If you were to watch an embryonic starfish develop, you would see that it begins life bilaterally, but switches to radial symmetry as it matures.
The name deuterostome means "mouth second", and refers to one important developmental feature unique to this group. To understand this feature, a little animal embryology is necessary. In the earliest stages of embryo development, when there are only a few cells and the embryo resembles a tiny globe of cells, a small pucker develops on one side of the embryo. This
Experiment 7
Title: Study of Deuterostomes
Aim:
1. To observe the external features of deuterostomes.
2. To study the characteristics of deuterostomes.
Materials:
1. Sea urchin
2. Amphioxus
3. Dogfish
4. Caecilian
5. Lizard
6. Microscope
Methods:
1. The specimen of sea urchin, amphioxus, dogfish, caecilian and lizard were observed.
2. The external features of specimens observed were drawn.
Discussion:
The Deuterostomia comprise one of the major groups within the animal kingdom, and it is probably the most familiar to you, since you are a deuterostome! Most of the deuterostomes belong to one of two groups that include the majority of its members -- the echinoderms (the spiny skinned starfish, sea urchins, and their relatives) and the chordates (which include fish and other vertebrates). It may be surprising to some that chorates and echinoderms are related -- most people do not feel close kinship with sea urchins and sea cucumbers -- but both groups share a number of important morphological and developmental features.
In turn, the deuterostomes belong to a larger group within the Animalia called the Bilateria, because they are bilaterally symmetrical with a left and a right side to their bodies. Obviously this is not true for adult echinoderms like starfish, and you may wonder what radially symmetric critters are doing in this group. The answer lies in the development of the embryo. If you were to watch an embryonic starfish develop, you would see that it begins life bilaterally, but switches to radial symmetry as it matures.
The name deuterostome means "mouth second", and refers to one important developmental feature unique to this group. To understand this feature, a little animal embryology is necessary. In the earliest stages of embryo development, when there are only a few cells and the embryo resembles a tiny globe of cells, a small pucker develops on one side of the embryo. This