Comparative Anatomy Invertebrate Project
ECOLOGY OF ANIMALS
Porifera:
Sponges interact with many of the organisms around it. For example, pecten sponge is found on scallop shells. The pecten sponge has a mutually beneficial relationship with the scallops. The sponge covers the shell and offers protection from the sea while the sponges gains substratum. The boring sponge burrows into the shells of various molluscs. Like a tree sponges grow in branches stretching towards the most amount of sunlight. This is vital for the photosynthesis process.
Cnidaria:
The Cnidaria differ from the Porifera. Cnidaria have radial symmetry while Porifera are asymmetrical. Cnidaria also have extracellular digestion while Porifera have intracellular digestion. While Porifera just filter feed the ocean water, Cnidaria find their prey and paralyze it then bring it in and consume it. Both the Porifera and Cnidaria use diffusion for respiration, circulation, and excretion. The Porifera has no nervous system but the Cnidaria however has a nerve net. Again, both the Cnidaria and Porifera are asexual and sexual but the Porifera uses internal fertilization while the Cnidaria uses external fertilization.
Annelida:
Annelids have much cell and tissue specialization. Their bodies are segmented, have bilateral symmetry, and contain a body cavity in which the internal organs reside. They have a digestion system, and they filter feed. Annelids have closed circulatory systems with blood vessels and excrete waste through nephridia. They have a central nervous system, with concentrated nerves at one end (also called cephalization). They are hermaphrodites, and reproduce externally.
Mollusca:
While Annelids differ from Cnidaria, Mollusca differ from Annelida. Mollusks have bilateral symmetry as well as a true coelom. They have extracellular digestion and a one-way digestive tract. They respire through diffusion with gills. They have closed circulatory systems with heart-like organs, and excrete wastes through a siphon.
Arthropoda:
Arthropods have bilateral symmetry and a true coelom as well. They have extracellular digestion with a one-way system and an anus to excrete waste, and respire with trachea and spiracles. They have an open circulatory system with a simple heart and at least one artery. They have a brain and ganglia. They can reproduce sexually and asexually, through internal fertilization.
Reflection
I, personally, am very interested in the topic of evolution, so dissecting each individual this way, in order from least complex to most complex, was very interesting, and I enjoyed learning and hypothesizing as to why they evolved certain characteristics. Again, like with other labs in this class, we enjoyed doing things independently; I think it's a great way to learn as it gets you interested in the project and has you teach yourself as you go along, which I like very much. I would like to study more about how certain body systems may have developed and under what conditions, as looking at less-obvious structures causes me to wonder. I would also like to learn more about the more distant ancestors of these organisms we dissected, and how they related or differed from these animals.
Porifera:
Sponges interact with many of the organisms around it. For example, pecten sponge is found on scallop shells. The pecten sponge has a mutually beneficial relationship with the scallops. The sponge covers the shell and offers protection from the sea while the sponges gains substratum. The boring sponge burrows into the shells of various molluscs. Like a tree sponges grow in branches stretching towards the most amount of sunlight. This is vital for the photosynthesis process.
Cnidaria:
The Cnidaria differ from the Porifera. Cnidaria have radial symmetry while Porifera are asymmetrical. Cnidaria also have extracellular digestion while Porifera have intracellular digestion. While Porifera just filter feed the ocean water, Cnidaria find their prey and paralyze it then bring it in and consume it. Both the Porifera and Cnidaria use diffusion for respiration, circulation, and excretion. The Porifera has no nervous system but the Cnidaria however has a nerve net. Again, both the Cnidaria and Porifera are asexual and sexual but the Porifera uses internal fertilization while the Cnidaria uses external fertilization.
Annelida:
Annelids have much cell and tissue specialization. Their bodies are segmented, have bilateral symmetry, and contain a body cavity in which the internal organs reside. They have a digestion system, and they filter feed. Annelids have closed circulatory systems with blood vessels and excrete waste through nephridia. They have a central nervous system, with concentrated nerves at one end (also called cephalization). They are hermaphrodites, and reproduce externally.
Mollusca:
While Annelids differ from Cnidaria, Mollusca differ from Annelida. Mollusks have bilateral symmetry as well as a true coelom. They have extracellular digestion and a one-way digestive tract. They respire through diffusion with gills. They have closed circulatory systems with heart-like organs, and excrete wastes through a siphon.
Arthropoda:
Arthropods have bilateral symmetry and a true coelom as well. They have extracellular digestion with a one-way system and an anus to excrete waste, and respire with trachea and spiracles. They have an open circulatory system with a simple heart and at least one artery. They have a brain and ganglia. They can reproduce sexually and asexually, through internal fertilization.
Reflection
I, personally, am very interested in the topic of evolution, so dissecting each individual this way, in order from least complex to most complex, was very interesting, and I enjoyed learning and hypothesizing as to why they evolved certain characteristics. Again, like with other labs in this class, we enjoyed doing things independently; I think it's a great way to learn as it gets you interested in the project and has you teach yourself as you go along, which I like very much. I would like to study more about how certain body systems may have developed and under what conditions, as looking at less-obvious structures causes me to wonder. I would also like to learn more about the more distant ancestors of these organisms we dissected, and how they related or differed from these animals.