The notochord is the defining structure of the chordates, and has essential roles in vertebrate development. It is a flexible, rod-shaped structure that is in the embryonic stage of all chordates. It gives the skeletal support and is found in between the digestive tube and nerve cord. In some animal chordates lifetimes it is the main axial support in the body. The dorsal hollow nerve cord is the only feature unique to all chordates. It is located at the top of the animal, above the notochord. During the development of the nerve cord the ectoderm rolls into a hollow tube. The nerve cord grows into the brain and spinal cord of most chordates which means it is part of the central nervous system. Pharyngeal slits, filter food for animals that live underwater, also known as invertebrate chordates. The pharyngeal slits allow the water to escape when it enters the mouth when the animal is eating. In most land animals, including mammals, the slits are existent only during embryonic development. The post-anal tail elongation of the body that grows past the anus. The tail has skeletal elements and muscles to help with movement of marine animals. In land vertebrates the tail assists with balance, signalling and attracting the opposite sex. Mammals are split into three main groupings, monotreme, marsupial and placental. They divided from how their babies develop. Monotremes are the mammals that lay eggs. They are usually characterised with reptilian and birdlike features such as they hatch from eggs and they only have one hole for intestinal, urinary, and genital organs called the cloaca. Female monotreme give their young milk through their due to not having teats. There are only two types of monotremes which are the duck-billed platypus and the echidnas, found in Australia and New Guinea.
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This is because the young develops in their mother uterus and are birthed. They also feed their offspring with milk. The only real difference between marine and land mammals is the gestation period and the fact that marine mammals give birth in water. For instance the prenatal period for humans can be from 38 to 40 weeks, 10 months, whereas killer whales are pregnant for 15 to 18 months.
Orcas are classified under the Delphinidae family of dolphins and porpoises. All dolphins are a part of the Cetacean order which is the toothed whale suborder. There characteristics the make it a part of the Delphinidae family are, that like dolphins, orcas have teeth, streamlined bodies and rounded head that tapers into a distinct beak. The main physical feature that ensures that orcas are dolphins is the presence of a melon. The melon is what assists with echolocation which only exists in dolphins. They use echolocation to hunt for prey and navigate their ocean home. The killer whale are considered dwarfed by baleen whales, like the blue whale, which is the biggest animal in the world. When they are swimming, the mammals make low frequency sounds that reflect back to them, helping them understand the landscape of the ocean floor and to find food. The killer whale also shares many behavioural traits with dolphins. Most dolphin species live in pods and use cooperative hunting techniques. They are mostly found near the shore and don't dive very deep. Orcas prey on other dolphin species and other animals that somewhat live land, such as seals, polar bears and
This is because the young develops in their mother uterus and are birthed. They also feed their offspring with milk. The only real difference between marine and land mammals is the gestation period and the fact that marine mammals give birth in water. For instance the prenatal period for humans can be from 38 to 40 weeks, 10 months, whereas killer whales are pregnant for 15 to 18 months.
Orcas are classified under the Delphinidae family of dolphins and porpoises. All dolphins are a part of the Cetacean order which is the toothed whale suborder. There characteristics the make it a part of the Delphinidae family are, that like dolphins, orcas have teeth, streamlined bodies and rounded head that tapers into a distinct beak. The main physical feature that ensures that orcas are dolphins is the presence of a melon. The melon is what assists with echolocation which only exists in dolphins. They use echolocation to hunt for prey and navigate their ocean home. The killer whale are considered dwarfed by baleen whales, like the blue whale, which is the biggest animal in the world. When they are swimming, the mammals make low frequency sounds that reflect back to them, helping them understand the landscape of the ocean floor and to find food. The killer whale also shares many behavioural traits with dolphins. Most dolphin species live in pods and use cooperative hunting techniques. They are mostly found near the shore and don't dive very deep. Orcas prey on other dolphin species and other animals that somewhat live land, such as seals, polar bears and