Which phylum includes humans snakes and sharks

Insects, spiders, centipedes, lobsters, and crabs are all a rthropod s. In contrast, members of the phylum Mollusca have soft, unsegmented bodies that are usually, but not always, enclosed in hard shells. They also usually have at least one strong foot that helps them move. Octopi, squids, cuttlefish, snails, slugs, clams, and other shellfish are m ollus k s. There are at least 33 phyla plural of phylum of animals. Humans are members of the phylum Chordata.

All of the chordates have elongated bilaterally symmetrical bodies. That is to say, the left and right sides are essentially mirror images of each other.

If there are two functionally similar body parts, they are usually found roughly equidistant from the center line, parallel to each other. Note the location of the woman's eyes, nostrils, and cheeks relative to the center line of her body. At some time in their life cycle, chordates have a pair of lateral gill slits or pouches used to obtain oxygen in a liquid environment. In the case of humans, other mammals, birds, and reptiles, lungs replace rudimentary gill slits after the embryonic stage of development.

Frogs replace them with lungs in the transition from tadpoles to adults. Fish retain their gill slits all of their lives. Chordates also have a notochord at some phase in their life cycle.

This is a rudimentary internal skeleton made of stiff cartilage that runs lengthwise under the dorsal surface of the body. Generally, there is a single hollow nerve chord on top of the notochord.

Among humans and the other vertebrates , the notochord is replaced by a more complex skeleton following the embryonic stage of development. Members of the phylum Chordata also often have a head, a tail, and a digestive system with an opening at both ends of the body. In other words, the body organization is essentially that of a tube in which food enters one end and waste matter passes out of the other.

These have flowers for reproduction, produce seeds protected inside fruits, and range from small grasses to huge trees e. The other phyla are non-flowering, often less conspicuous plants: the non-flowering trees conifers produce seeds in cones e. Animal Kingdom There is a tendency for children to only regard large land mammals as animals. The animal kingdom includes organisms as diverse as humans including babies and children! Animals are multicellular, heterotrophic organisms.

Their cells are without cell walls, but enclosed within a cell membrane. They have a nervous system and are usually able to move themselves around. Cnidarians have soft bodies and a ring of tentacles around the mouth. Usually found in marine habitats e. Echinoderms have bodies protected by calcareous plates and spines. Numerous tube feet used for locomotion.

Restricted to marine habitats e. Molluscs have soft, non-segmented bodies, often with a calcareous shell. Live on land e. Segmented worms have long, segmented bodies, roundish in cross section, often with bristle-like chaetae which help with movement.

Live in soil e. Flatworms have flattish, non-segmented bodies. Live in ponds and damp places e. Roundworms nematodes have long, whitish, non-segmented bodies, round in cross section. Some live in soil, marine or freshwater habitats, others are internal parasites of animals and plants. Arthropods have hard exoskeletons, segmented bodies and jointed legs.

Females deposit a number of eggs and males deposit a number of sperms. In evolutionary history, the fossil records of the chordates can easily be found around million years ago in the early period of Cambrian when the fossils of the jawless fish appeared. The oldest fossil of the family of Chordata was explored in in China and was placed in the species of Yunnanozoon lividum.

Extensive research has been done on the evolution of the chordates, and thus, the researchers believed that the earliest fossils of the tetrapod, mammals, and birds were found approximately , 80, and million years ago. The basic reason behind the evolution of the chordates is the major changes that occur in the habitat and the earliest chordates that are reported in the literature were all the aquatic animals such as tunicates and lancelets.

Thus, with their progressions and evolutions, they first moved to freshwater ponds and then finally towards land. The intermediate phase in which the chordates moved to land from water is shown by many species of amphibians that still prefer to live in both land and aquatic habitats. Additionally, the expansion of the aerial population in the birds also brought a wide range of diversities in the phylum of chordates.

The researchers have thoroughly investigated the evolutionary history of chordates and have presented four major scenarios. Paedomorphosis hypothesis , Inversion hypothesis , Aboral-dorsalization hypothesis , and the Auricularia hypothesis are among those four hypotheses developed. The first hypothesis debated on whether the ancestors of the chordates were free-living or were sensible.

Similarly, the remaining three models enlightened the biology behind the evolutionary development of the chordates and how they originated from a common ancestor. Thus, it is concluded that all four models are connected and supporting arguments in each of them sometimes may overlap. There are three Chordata subphyla i. Urochordata Tunicata , Cephalochordata, and Vertebrata Craniata.

The salient features on which all of these three classes have been categorized are the notochord, nerve cord, branchial slits, endostyle, postanal tail, and a myotome. Chordata has been placed in the super phyletic Deuterostomia along with the phylum Hemichordata and Echinodermata.

The common ancestor from which the chordates have evolved are deuterostomes. Thus, the majority of the scientists believe that among all the three phyla of chordates, the first one that evolved was the Urochordata followed by Cephalochordata and lastly Vertebrata. The term protochordate has been extensively used in the phylogeny of chordates. The detailed analysis of the traditional reviews on the phylogeny of chordates has been elaborated on in Figure 5.

On the other hand, there are many questions that often come to the minds of readers regarding the evolution of the chordates and it has been seen that a reasonable answer to all of such queries can easily be given via molecular phylogeny.

The broader classification in this field of science has allowed the researchers to reclassify the metazoan groups on the phylum level. Protostomes and deuterostomes were the traditional categories in which the Bilaterians and tripoblasts were placed. The protostomes were divided into acoelomates, Platyhelminthes, and pseudocoelomates based on the modes of various formations in the cavity of the body.

The said categories were not actively supported by the molecular phylogeny rather on the basis of the DNA sequences and the gene sequences of the protein-coding. The protostomes were again divided into two major groups as Lophotrochozoa and Ecdysozoa. A clade has been formed by the echinoderms and hemichordates. Another one is formed by the urochordates, vertebrates, and cephalochordates.

This has been confirmed by the findings via molecular phylogeny, mitochondrial and nuclear biology. Thus, it has been concluded that the former clade represents the Ambulacraria and the latter one shows the Chordata phylum.

Additionally, in Chordata, cephalochordates emerged first and the remaining two groups urochordates and vertebrates form a sister class. The recent view on the phylogeny of chordates has been shown also in Figure 5. Phylum Chordata has three subphyla: 1 Urochordata, 2 Cephalochordata, and 3 Vertebrata, as depicted in Figure 6.

There are very few species that belong in Cephalochordata and Urochordata. Most chordates belong in the subphylum Vertebrata vertebrates , e. Approximately, there are fifty thousand species in this subphylum. They are ubiquitous. They are found in various habitats, e. Chordata has a very peculiar feature; they possess bodies bilaterally symmetric making them unique to other animal phyla. The chordates are a member of the deuterostomes.

One of the characteristics of this group is the anus gets developed in the early embryonic stages before the mouth. Vertebrates are further divided into many classes, such as fishes, birds, reptiles, amphibians, and mammals. Reptiles are vertebrates with scaly, water-resistant skins. They lay shelled eggs and breathe air. They are cold-blooded, which means that they are unable to withstand the cold weather and widely depend on the temperature of its surrounding to maintain normal body temperature.

They usually have four limbs. Strong aromatics, even the ones that smell pleasant to us, can do that. This will keep mice and other rodents from visiting… a benefit all its own.

You may be surprised to learn that many gardeners go to great lengths to try to attract garter snakes! You can try to entice them by providing them with hiding places stacked rocks, sheets of plywood, or stumps and fresh water sources such as shallow fountains or ground-level birdbaths. Garter snakes are incredibly active. They come out both night and day. They are typically ground-dwellers, but they may also climb shrubs, vines, or trees to escape predators.

Some species of Garter snakes are even proficient swimmers. You should never pick up a snakeskin with your bare hands. This is because about 15 to 90 percent of snakes carry some Salmonella bacteria on their shed skins.

Consequently, touching it with your bare skin places you at risk of a bacterial infection. People apply snake skin to the skin for skin disorders, including sores, abscesses, boils, itching, scaly and itchy skin psoriasis , and scabies, as well as eye infections, cloudy spots in the eye, sore throat, and hemorrhoids.

Snake skin is also used in ointments and creams to reduce pain and stiffness.