The Evolution of Animals Essay

4. Modern taxonomists (scientists who classify organisms) no longer use the classification of the kingdom of Protists. List the three other kingdoms of Eukarya.

They must be eukaryotic, meaning they have nucleus, and in the domain Eukarya. In the Linnaean classification this could be in the kingdom Protista like a paramecium. Another Linnaean classification of this could be in kingdom Animalia, since they are heterotrophs and their cells contain a nucleus. They could be grouped as predators, since the organism is engulfing another organism. They could also be grouped based on their locomotion. They could have cilia, legs, or even flagella.

Prokaryotes are the primitive, simple cells of bacteria and their bacteria-like Archaea. Eukaryotes, which include the most advanced cells of animals, plants, fungi, protozoan, algae, and slime & water molds.

During the Cambrian Period there was an explosion of life forms. Most of these were in the water. Many animals with no backbones lived in the shallow seas. These animals were invertebrates.

They are known as a diverse group of unicellular eukaryotic organisms. They are also defined as a single celled organism with animal like behaviour. Protozoa are microscopic cells that range from a size from 10 to 52 micrometers. Some protozoa are larger than most. For example the xenophyophores are around 20 centimetres in diameter. Free living forms are restricted to moist environments, such as soil, mosses and aquatic habitats. Many protozoa are symbionts.

Ribosomes then started copy themselves into cell-like structure with a thin membrane and cytoplasm. Eventually, cells starting storing DNA. Lateral transfer diversified the cells genetic makeup. From this community of cells came the three domains, known as bacteria, eukaryotes, and archaea. Bacteria and archaea are together called

Bacteria and Archaea are prokaryotic, which are mostly single-celled incomplex microorganisms. Both Bacteria and Archaea have a variety of prokaryotes classified in multiple kingdoms (Reece, et al., Campbell Biology, 2014). There are a number of scientists who believe that Archaea cells may be the precursor to Eukaryotic cells and that they have more in common with Eukaryotes than Prokaryotes (Madigan, Martinko, & Dunlap, 2009).

Microscopic  organisms  known  as  cyanobacteria are  interesting  for  the  following  reasons: [SELECT  ALL  THAT  APPLY] Select  one  or  more: A.  Oxygen  produced  by  their  photosynthesis is  thought  to  be  responsible  for  the  "great oxygenation  event"  about  2.3  billion  years ago.   B.  The  methane  they  produce  is  a greenhouse  gas  that  could  have  helped warm  the  early  Earth,  helping  to  resolve  the Early-­faint-­Sun  paradox. C.  The  chloroplasts  that  carry  out photosynthesis  in  green  plants  are evolutionary  descendents  of  early cyanobacteria.   D.  They  are  known  to  be  the  earliest  forms of  life  on  Earth.

Stromatolite forms and is the first organisms on the earth they were formed by very thin layers of single-celled organisms.

Sponges are considered part of the Animal Kingdom because sponges are multicellular. They are known be diploblastic, which means having two layers of cells. Adult Sponges, may have several cell layers, but originally, they all arise from the two layers that were present in the early embryo (Dawkins 2004). Most sponges are asymmetrical, however some of them show the radial symmetry (Dawkins 2004). Sponges do not have a coelom. A coelom is a cavity within the body in which the heart, intestines, kidney, lungs, etc., they are located, and it is sealed off from the outside world. The body cavity of sponges is large, and it is open to the outside world, also it’s enables the sponge to consume food (Dawkins 2004).

The gastropod shell is a single structure that shared the same developmental process and similar functions when it appeared during the Cambrian explosion (AUTHOR 1).

Prokaryotic Cells All living things are made of cells, and cells are the smallest units that can be alive. Life on Earth is classified into five kingdoms, and they each have their own characteristic kind of cell. However the biggest division is between the cells of the prokaryote kingdom (monera, the bacteria) and those of the other four kingdoms (animals, plants, fungi and protoctista), which are all eukaryotic cells. Prokaryotic cells are smaller and simpler than eukaryotic cells, and do not have a nucleus. Prokaryotic means 'pre-nucleus' and eukaryotic means 'true nucleus'.

Prokaryote cells - bacteria and archeans. They are single celled organisms, where the DNA is not separate from the cytoplasm. These prokaryote cells formed the earliest and most primitive life on earth.

Protista life is approximately estimated to be 1.5 billion years old.Protista can be found from the depths of the ocean to the dead organisms, also as parasites in animals and plants. Protista feeds on particles dissolved in water which can be other bacteria, and because protista are incapable to move, they are found in aquatic and marine habitats such as: streams, lakes, freshwater ponds, and oceans. Protista that occupy marina habitat are the most important. Algae is a type of marine protista which produce 30 to 50 percent of the earth’s oxygen and live near water’s surface. Also algae supplies the make up of the sea floor. There are over 100,000 living species of protists.

     Coral animals begin life as free-floating larvae, but settle on the sea floor in sedentary colonies. The term "coral" applies both to these animals and to their skeletons, particularly the skeletons of stone-like corals (Discover 1997).