Phylum CHORDATA
Phylum chordata includes the well-known vertebrates such as fish, amphibians, reptiles, birds and mammals. They exist in marine, freshwater and terrestrial habitats. Phylum chordata is divided into protochordates and vertebrates.
ECOLOGICAL ROLE
Chordates are a main food source for humans, many are farmed as livestock for agricultural purposes, and they live in our homes as pets.
Chordates are a main food source for humans, many are farmed as livestock for agricultural purposes, and they live in our homes as pets.
MOVEMENT STRUCTURES/TYPE
Different chordates have different mechanisms to help them move. Those that are segmented generally have four segments, and use them to help them move such as legs, others have wings or tails to help propel themselves, or use wave-like motions. The tail contains skeletal elements and muscles that provide a source of locomotion in aquatic species, allowing them to swim. In some terrestrial vertebrates, the tail also helps with balance, courting, and signalling when danger is near.
Different chordates have different mechanisms to help them move. Those that are segmented generally have four segments, and use them to help them move such as legs, others have wings or tails to help propel themselves, or use wave-like motions. The tail contains skeletal elements and muscles that provide a source of locomotion in aquatic species, allowing them to swim. In some terrestrial vertebrates, the tail also helps with balance, courting, and signalling when danger is near.
BODY COVERING; CELL LAYERS; LEVEL OF ORGANISATION; PROTECTION
Chordates are bilaterally symmetrical, deuterostomes, have segmented bodies, a well developed coelom, and have the following features at some point in their life, either in adult form or in the embryonic stage: Pharyngeal slits which are openings that connect the inside of the throat to the outside of the neck, that can often be used as gills for fish, but in other chordates they are part of a filter feeding system. They have a dorsal hollow nerve cord which are a bundle of nerve fibres which runs down the back and connects the brain with the lateral muscles and other organs. They have a post-anal tail which is an extension of the body past the anal opening. They have a ventral heart with dorsal and ventral blood vessels, a closed circulatory system, and a complete digestive system. Some chordates are vertebrates while others are invertebrates.
Chordates are bilaterally symmetrical, deuterostomes, have segmented bodies, a well developed coelom, and have the following features at some point in their life, either in adult form or in the embryonic stage: Pharyngeal slits which are openings that connect the inside of the throat to the outside of the neck, that can often be used as gills for fish, but in other chordates they are part of a filter feeding system. They have a dorsal hollow nerve cord which are a bundle of nerve fibres which runs down the back and connects the brain with the lateral muscles and other organs. They have a post-anal tail which is an extension of the body past the anal opening. They have a ventral heart with dorsal and ventral blood vessels, a closed circulatory system, and a complete digestive system. Some chordates are vertebrates while others are invertebrates.
SUPPORT
Chordates have a bony or cartilaginous endoskeleton. They have a notochord which is a rod running underneath and supporting the nerve cord that stiffens the body, and acts as support during locomotion. In most adult chordates, the notochord disappears and is replaced by the vertebral column (spine). It's located between the digestive tube and the nerve cord, providing skeletal support throughout the length of the body. In some chordates, it acts as the primary axial support of the body throughout the animal's entire lifetime. The skeleton and muscles of the visceral arches are the source of great structure in the vertebrates. Ex., In humans and other mammals, visceral arch derivatives include the jaw, facial muscles, the embryonic cartilaginous skeleton of the lower jaw, the alisphenoid bone in the side wall of the braincase, the three middle ear ossicles (malleus, incus and stapes), the skeleton, muscles of the tongue, muscles of the larynx, and the cartilaginous tracheal rings.
OBTAINING NUTRIENTS
All chordates eat through ingestion rather than through absorption. Chordates have jaws with or without teeth, than help consume and break down the food. Those without teeth or jawbones, rely on the enzymes in their esophagus to break down the food. Different chordates can be herbivores, carnivores or even omnivores. Majority of chordates consume food through their mouths, which is transported into the stomach, where it is digested and broken down by secreting enzymes, and in which the body collects the nutrients from the food. The intestine completes the process of digestion and nutrient absorption. Depending on the species, some have more organs than others that help with other digestive processes such as livers, pancreas and kidneys. In organisms that live in aquatic environments, the pharyngeal slits allow for water to exit when it enters the mouth while feeding.
All chordates eat through ingestion rather than through absorption. Chordates have jaws with or without teeth, than help consume and break down the food. Those without teeth or jawbones, rely on the enzymes in their esophagus to break down the food. Different chordates can be herbivores, carnivores or even omnivores. Majority of chordates consume food through their mouths, which is transported into the stomach, where it is digested and broken down by secreting enzymes, and in which the body collects the nutrients from the food. The intestine completes the process of digestion and nutrient absorption. Depending on the species, some have more organs than others that help with other digestive processes such as livers, pancreas and kidneys. In organisms that live in aquatic environments, the pharyngeal slits allow for water to exit when it enters the mouth while feeding.
RESPIRATION
In typical fish-like aquatic vertebrates, the walls of the pharyngeal clefts develop into gills that are organs of gas exchange between the water and blood. Terrestrial vertebrates respire through the use of lungs or diffusion.
In typical fish-like aquatic vertebrates, the walls of the pharyngeal clefts develop into gills that are organs of gas exchange between the water and blood. Terrestrial vertebrates respire through the use of lungs or diffusion.
CIRCULATION
Chordates are either warm blooded or cold blooded, depending on the group the chordate belongs to. Chordates have a closed circulatory system, which can either be single-looped or double-looped. The blood is closed at all times within vessels of different sizes and a thick wall. In most chordate groups, the blood is pumped by a heart through cavities in the body, whereas in other groups, the blood is circulated by the contraction of the blood vessels. Un-oxygenated blood is driven forward by the ventral aorta, which then passes through a series of arteries, and goes where gas exchange takes place. The oxygenated blood then flows to the body, returning to the dorsal aorta. The blood of vertebrates passes through tiny vessels called capillaries.
Chordates are either warm blooded or cold blooded, depending on the group the chordate belongs to. Chordates have a closed circulatory system, which can either be single-looped or double-looped. The blood is closed at all times within vessels of different sizes and a thick wall. In most chordate groups, the blood is pumped by a heart through cavities in the body, whereas in other groups, the blood is circulated by the contraction of the blood vessels. Un-oxygenated blood is driven forward by the ventral aorta, which then passes through a series of arteries, and goes where gas exchange takes place. The oxygenated blood then flows to the body, returning to the dorsal aorta. The blood of vertebrates passes through tiny vessels called capillaries.
EXCRETION
Majority of chordates expel waste through their anus, but in some aquatic cases, ammonia waste is diffused through the gills.
Majority of chordates expel waste through their anus, but in some aquatic cases, ammonia waste is diffused through the gills.
RESPONSE
They have a dorsal hollow nerve cord, which are a bundle of nerve fibres that run down the length of the back and connects the brain with the lateral muscles and other organs. Together, the brain and spinal cord are the central nervous system to which peripheral sensory and motor nerves connect. The nerve cord found in most chordate embryos, develops into the brain and spinal cord that make up the central nervous system. Most chordates have two eyes and at least a minimal hearing system, if not an excellent one. The chordates have the most developed brains and complex nervous systems in all the animal phyla.
They have a dorsal hollow nerve cord, which are a bundle of nerve fibres that run down the length of the back and connects the brain with the lateral muscles and other organs. Together, the brain and spinal cord are the central nervous system to which peripheral sensory and motor nerves connect. The nerve cord found in most chordate embryos, develops into the brain and spinal cord that make up the central nervous system. Most chordates have two eyes and at least a minimal hearing system, if not an excellent one. The chordates have the most developed brains and complex nervous systems in all the animal phyla.
REPRODUCTION
All chordates reproduce sexually, but some fish and lizards can reproduce asexually. Majority of chordates are of separate sexes. Both internal and external fertilization occur and parent care is also common among some groups. When sexually reproduction occurs, the fertilized egg sits inside the female or in a specialized pouch for a period of time, until the egg is ready to be laid, and or the young is ready to be birthed alive. External fertilization consists of eggs and sperm being released into the water and are fertilized outside of a body.
All chordates reproduce sexually, but some fish and lizards can reproduce asexually. Majority of chordates are of separate sexes. Both internal and external fertilization occur and parent care is also common among some groups. When sexually reproduction occurs, the fertilized egg sits inside the female or in a specialized pouch for a period of time, until the egg is ready to be laid, and or the young is ready to be birthed alive. External fertilization consists of eggs and sperm being released into the water and are fertilized outside of a body.