In Biology What Is A Phylum
In biology, a phylum is a division of organism below kingdom and above class . There are 38 animal phyla, with nine phyla Mollusca, Porifera, Cnidaria, Platyhelminthes, Nematoda, Annelida, Arthropoda, Echinodermata, and Chordata making up the vast majority of all animals. The phyla Arthropoda and Nematoda are the most successful, with the former containing between 1 and 10 million species, and the latter containing between 80,000 and 1 million species. Animal phyla are broadly classified into two groups: deuterostomes and protostomes, distinguished from differences in embryonic development.
Only three new animal phyla have been discovered in the last century, although over ten animals formerly put under other phyla have been recognized as their own phyla. Different phyla have fundamental differences in their body plans, and each make up a monophyletic group, meaning the phylum consists of all the descendants of a common ancestor, and none that aren’t. Biological groups that may consist of numerous phyletic groups, such as worms, are termed polyphyletic. The evolution of biological taxonomy has generally been one of strictly defining one phylum from another based on clearly describable physical differences as well as genetic similarity.
What Is The Definition Of Kingdom In Biology
A “kingdom” in biology is a classification of living things. Organisms belong to one of six kingdoms of life. The current kingdoms are the Archaebacteria, Eubacteria, protists, fungi, plants and animals.
At one time, only five kingdoms existed, with the Archaebacteria and Eubacteria being placed in one kingdom: Monera. This single kingdom exhibited so much diversity that it has since warranted division into two kingdoms.
The Archaebacteria are bacteria that live in inhospitable regions of the world, such as hot thermal vents. The Eubacteria consists of the other types of bacteria, many of which have contact with humans. The protists are single-celled organisms that can usually move on their own. The fungi consist of organisms that are single celled, have cell walls and obtain their food through absorption of nutrients. Plants are multicellular organisms that can make their own food through the process of photosynthesis. Animals are multicellular organisms that must obtain their nutrients from consuming other organisms.
Two Empires Four Kingdoms
The discovery that bacteria have a radically different cell structure from other organisms â the bacterial cell has one or two membranes that lie at or near its surface, whereas other organisms have a more complex structure with a nucleus and other organelles divided by intracellular membranes â led Chatton to propose a division of life into two empires: organisms with a nucleus in Eukaryota and organisms without in Prokaryota.
Chatton’s proposal was not taken up immediately a more typical system was that of Herbert Copeland, who gave the prokaryotes a separate kingdom, originally called Mychota but later referred to as Monera or Bacteria. Copeland’s four-kingdom system placed all eukaryotes other than animals and plants in the kingdom Protista.
It gradually became apparent how important the prokaryote/eukaryote distinction is, and Stanier and van Niel popularized Chatton’s two-empire system in the 1960s.
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Other Members Of The Division Coniferophyta
| Podocarpus gracilior, a member of the Podocarpaceae native to eastern Africa. Although it is sometimes called “fern pine” it does not belong to the genus however, like pines and other cone-bearing species, it does belong to the Division Coniferophyta. Minute female cones are composed of 2-4 reduced scales, but usually only one scale bears an ovule that matures into a seed. There is little resemblance to a cone in the mature seed. The seed has a hard coat surrounded by a fleshy outer layer . The drupelike seed often sits on a fleshy red or purple base or cone axis that is called an aril in some references. The seeds are similar to the California nutmeg and Pacific yew , members of the closely-related Yew Family . In the latter species, the naked seed sits partially exposed in a red, cup-shaped aril. Podocarpus seeds are often referred to as fleshy fruits called drupes, but this is incorrect because drupes develop from the ovaries of flowering plants. Another group of conifers with fleshy seed-bearing structures are the junipers in the Cypress Family . Junipers actually produce small cones with fleshy, fused scales bearing one-several seeds. Podocarpus is a dioecious species, with separate male and female trees in the population. Podocarpus has an ancient lineage dating back to distant relatives that lived during the Jurassic Period 170 million years ago. |
Summary Kingdom Vs Domain
Classification of living organisms is important to identify and study their characteristics and phylogenetic relationships. Classification systems include different hierarchical levels. Among the different hierarchical levels, domain and kingdom are two main levels. Accordingly, domain is a category above the kingdom level. There are five kingdoms monera, protista, fungi, plantae and animalia. On the other hand, all living organisms belong to three domains namely, bacteria, archaea and eukarya. Similarly, domain Eukarya includes protista, fungi, plantae and animalia. Hence, this is the difference between kingdom and domain.
Reference:
1. College of Education Homepage Comments, OnlineProvider. Available here 2. Experiment on Flagellar Regeneration in Chlamydomonas. Available here
Image Courtesy:
1.âBiological classification L Pengo vflipâBy Peter Halasz. â Own work, via Commons Wikimedia 2.â3 domains of lifeâBy C3lin â Paint- own work, via Commons Wikimedia
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Parasitism: Role As Pathogens
Some protists are significant parasites of animals , plants or even of other protists. Protist pathogens share many metabolic pathways with their eukaryotic hosts. This makes therapeutic target development extremely difficult a drug that harms a protist parasite is also likely to harm its animal/plant host. A more thorough understanding of protist biology may allow these diseases to be treated more efficiently. For example, the apicoplast present in apicomplexans provides an attractive target for treating diseases caused by dangerous pathogens such as plasmodium.
Recent papers have proposed the use of viruses to treat infections caused by protozoa.
Researchers from the Agricultural Research Service are taking advantage of protists as pathogens to control red imported fire ant populations in Argentina. Spore-producing protists such as Kneallhazia solenopsae can reduce red fire ant populations by 53100%. Researchers have also been able to infect phorid fly parasitoids of the ant with the protist without harming the flies. This turns the flies into a vector that can spread the pathogenic protist between red fire ant colonies.
The Major Divisions Of Land Plants
Land plants are classified into two major groups according to the absence or presence of vascular tissue, as detailed in . Plants that lack vascular tissue formed of specialized cells for the transport of water and nutrients are referred to as nonvascular plants. The bryophytes, liverworts, mosses, and hornworts are seedless and nonvascular, and likely appeared early in land plant evolution. Vascular plants developed a network of cells that conduct water and solutes through the plant body. The first vascular plants appeared in the late Ordovician and were probably similar to lycophytes, which include club mosses and the pterophytes . Lycophytes and pterophytes are referred to as seedless vascular plants. They do not produce seeds, which are embryos with their stored food reserves protected by a hard casing. The seed plants form the largest group of all existing plants and, hence, dominate the landscape. Seed plants include gymnosperms, most notably conifers, which produce naked seeds, and the most successful plants, the flowering plants, or angiosperms, which protect their seeds inside chambers at the center of a flower. The walls of these chambers later develop into fruits.
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What A Newfound Kingdom Means For The Tree Of Life
Neither animal, plant, fungus nor familiar protozoan, a strange microbe foretells incredible biodiversity yet to be discovered
From Quanta Magazine .
The tree of life just got another major branch. Researchers recently found a certain rare and mysterious microbe called a hemimastigote in a clump of Nova Scotian soil. Their subsequent analysis of its DNA revealed that it was neither animal, plant, fungus nor any recognized type of protozoanthat it in fact fell far outside any of the known large categories for classifying complex forms of life . Instead, this flagella-waving oddball stands as the first member of its own supra-kingdom group, which probably peeled away from the other big branches of life at least a billion years ago.
Its the sort of result you hope to see once in a career, said Alastair Simpson, a microbiologist at Dalhousie University who led the study.
Impressive as this finding about hemimastigotes is on its own, what matters more is that its just the latest of a quietly and steadily growing number of major taxonomic additions. Researchers keep uncovering not just new species or classes but entirely new kingdoms of liferaising questions about how they have stayed hidden for so long and how close we are to finding them all.
Beyond answering such fundamental questions, the simple joy of discovery motivates researchers like Burki and Eglit. The microbial world is a wide-open frontier, said Eglit. Its thrilling to explore whats out there.
Sporangia In The Seedless Plants
The sporophyte of seedless plants is diploid and results from syngamy or the fusion of two gametes . The sporophyte bears the sporangia , organs that first appeared in the land plants. The term sporangia literally means spore in a vessel, as it is a reproductive sac that contains spores. Inside the multicellular sporangia, the diploid sporocytes, or mother cells, produce haploid spores by meiosis, which reduces the 2n chromosome number to 1n. The spores are later released by the sporangia and disperse in the environment. Two different types of spores are produced in land plants, resulting in the separation of sexes at different points in the life cycle. Seedless nonvascular plants produce only one kind of spore, and are called homosporous. After germinating from a spore, the gametophyte produces both male and female gametangia, usually on the same individual. In contrast, heterosporous plants produce two morphologically different types of spores. The male spores are called microspores because of their smaller size the comparatively larger megaspores will develop into the female gametophyte. Heterospory is observed in a few seedless vascular plants and in all seed plants.
When the haploid spore germinates, it generates a multicellular gametophyte by mitosis. The gametophyte supports the zygote formed from the fusion of gametes and the resulting young sporophyte or vegetative form, and the cycle begins anew .
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What Is A Kingdom In Biology
The system of biological kingdoms is the way in which science classifies living things according to their ancestry over the course of evolution. This means that all the species that make up these five large groups – some recent theories split them further into six or even seven – have common ancestors and therefore share some of their genes and belong to the same family tree.
As well as the kingdoms of living things there are other taxonomic categories within the same classification system such as, for instance, domain, phylum, class, order, family, genus and species. They all follow a hierarchical order and are dependent on each other, so some divisions include others. In this way, the domain includes the kingdom, the kingdom the phylum, the phylum the class, and so on.
Selection & Genetic Drift In California Cypress
Millions of years ago, cypress woodlands containing one or more ancestral species of the cone-bearing genus Cupressus once dominated vast areas of California. During the past 20 million years, as mountains were uplifted and the climate became increasingly more arid, most of these extensive cypress woodlands vanished from the landscape. In some areas, the cypress were probably unable to compete with more drought resistant, aggressive species, such as impenetrable chaparral shrubs and desert scrub. Although cypress are fire-adapted with serotinous seed cones that open after a fire, they are vulnerable if the fire interval occurs too frequently, before the trees are old enough to produce a sufficient cone crop. Chaparral shrubs quickly resprout after a fast-moving brush fire from well-established subterranean lignotubers. This may explain why some cypress groves occur in very rocky, sterile sites with poor soils where the chaparral shrubs can’t compete as well.
| See Article About Brush Fires In California |
| Left: Seed cones of cypress from groves in southern California. A. Tecate cypress , B. Sargent cypress , C. Piute cypress , D. Cuyamaca cypress , E. Smooth-bark Arizona cypress , F. Rough-bark Arizona cypress . Right: Seed cones of cypress from groves in central and northern California. G. Monterey cypress , H. Gowen cypress , I. Santa Cruz cypress , J. Sargent cypress , K. Mendocino cypress , L. Macnab cypress , M. Modoc cypress . |
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The Classification Of Living Things Into Five Kingdoms
The first person to divide living things into five broad kingdoms was North American ecologist Robert Whittaker. This researcher proved in 1959 that fungi were not plant organisms – previously it was thought that they were – and a decade later he proposed the creation of the fungi kingdom to differentiate them from plants. Whittaker’s theory was widely accepted and the scientific community thereby added a new group to the previous four-kingdom system, established by the American biologist Herbert Copeland in 1956.
Animal kingdom
The kingdom Animalia is the most evolved and is divided into two large groups – vertebrates and invertebrates. These animals are multi-celled, heterotrophic eukaryotes with aerobic respiration, sexual reproduction and the ability to move. This kingdom is one of the most diverse and comprises mammals, fish, birds, reptiles, amphibians, insects, molluscs and annelids, among others.
Plant kingdom
Trees, plants and other species of vegetation make up part of the Plantae kingdom – one of the oldest, and characterised by its immobile, multicellular and eukaryotic nature. These autotrophic things, whose cells contain cellulose and chlorophyll are essential for life on Earth since they release oxygen through photosynthesis. As regards their method of reproduction, this may be either sexual or asexual.
The kingdoms of living things and their species at a glance.
Definition And Associated Terms
When Carl Linnaeus introduced the rank-based system of nomenclature into biology in 1735, the highest rank was given the name “kingdom” and was followed by four other main or principal ranks: class, order, genus and species. Later two further main ranks were introduced, making the sequence kingdom, phylum or division, class, order, family, genus and species. In 1990, the rank of domain was introduced above kingdom.
Prefixes can be added so subkingdom and infrakingdom are the two ranks immediately below kingdom. Superkingdom may be considered as an equivalent of domain or empire or as an independent rank between kingdom and domain or subdomain. In some classification systems the additional rank branch can be inserted between subkingdom and infrakingdom, e.g., Protostomia and Deuterostomia in the classification of Cavalier-Smith.
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Difference Between Kingdom And Domain
November 17, 2011 Posted by Samanthi
The key difference between kingdom and domain is that the kingdom is one of the five major groups of living organisms while the domain is one of the three taxonomic categories of living organisms above the kingdom level.
There were many attempts of classification of organisms on earth. Till 1977, kingdom system was universally accepted across the world. Starting from the two kingdoms system called the Linnaean system way back in 1758 when the life forms were divided into plants and animals, the world has come to recognize the three-domain system as the most current and the most scientific system of classification of organisms. Though there are some similarities, the kingdom system of classification of organisms has now been relegated to having relatively little significance since the three-domain system popularized in all parts of the world. The aim of this article is to find out the difference between kingdom and domain system of classification of organisms.
The Development Of Whittaker’s Five
Shortly after leaving Hanford, Whittaker published a brief note in Ecology, arguing that the traditional dichotomy between plants and animals was artificial . According to Whittaker, a better classification would recognize three broad kingdoms based on ecological trophic levels: producers , consumers , and decomposers . He acknowledged that these kingdoms did not correspond very closely with taxonomic groupings in the traditional two kingdoms or with alternative three- and four-kingdom revisions that had been proposed earlier by some taxonomists. Instead, he appealed to a combined ecological and evolutionary justification: All ecological communities, past and present, included producers, consumers, and decomposers. Although these groups were heterogeneous, the three nutritional modes that characterized the trophic levels were conceptually clear cut and represented three major directions of evolution. Whittaker argued that recognizing kingdoms by ecological function provided an intellectual coherence that was lacking in systems based on morphological characteristics or speculative phylogenetic relationships.
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Gametangia In The Seedless Plants
Gametangia are structures on the gametophytes of seedless plants in which gametes are produced by mitosis. The male gametangium, the antheridium, releases sperm. Many seedless plants produce sperm equipped with flagella that enable them to swim in a moist environment to the archegonia, the female gametangium. The embryo develops inside the archegonium as the sporophyte.
Are You Familiar With The Five Kingdoms Of Living Things
Millions of living things inhabit our planet, but did you know that they are divided into five separate kingdoms? Some, like animals and plants, are visible to the naked eye but others, like bacteria, can only be seen under a microscope. Let’s delve into the world of the five kingdoms of nature and find out a bit more about them.
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