The subphylum Hexapoda, known for a common body structure consisting of the famous three pairs of legs, abdomen, thorax and head, is divided into two taxonomic groups: the Entognatha and the Ectognatha (Sasaki et al., 2013). Within the Entognatha are the orders Diplura, Collembola, and Protura (Sasaki et al., 2013). These are all wingless orders (Sasaki et al., 2013). The Entognatha are marked by an entognathy, which is seen as their mouthparts being further inside their head, being enclosed by extensions of the head (Reiger et al., 2004). Within the Ectognatha is the class Insecta (Sasaki et al., 2013). This is further subdivided into the orders Pterygota, Zygentoma, and Archaeognatha (Sasaki et al., 2013). Ectognatha are classified by an …show more content…
This study analyzed sequence data of nucleic acids and found that the Hexapoda tree was in fact monophyletic (Reiger et al., 2004). Recent mitochondrial genomic sequencing data has shown that wingless collembolans and diplurians may not be as related to hexapods as originally thought (Sasaki et al., 2013).Based on the same mitochondrial genomic data, it has been inferred that collembolans and diplurians are more related to crustaceans (Sasaki et al., 2013). However, when nuclear molecular data such as rDNA and protein coding genes were analyzed for phylogenetic analysis, it was determined that Hexapoda is indeed monophyletic (Sasaki et al., 2013). By looking at all of these studies, it can clearly be seen that different phylogenies can be recovered by analyzing different characteristics of a group of organisms (Reiger et al., 2004; Sasaki et al., 2013).
Traditionally, the group Entognatha within the subphylum Hexapoda consists of the orders Diplura, Collembola, and Protura, which are classified into this group by their mouth structure, namely, the presence of entognathy (Luan et al., 2005). Further research on the mouthparts has identified two different kinds of entognathy, one of which is found in both Protura and Collembola while the second form is unique to the Diplura (Sekiya and Machida, 2011). According to molecular studies, the order Protura has been
Click here to unlock this and over one million essaysGet Access
The isopods used for this experiment range in color from gray to brown and were about 8.5 to 18 mm in length. Each Isopod’s head had one pair of antennae and one pair of antennules, both used to detect sensory stimuli from the environment around the pillbug. Their bodies were made of a hard thorax with seven segments and an abdomen. Each pillbug had seven pairs of legs, one for each segment of its thorax. Pill bugs breathe through gill-like structures and must live in moist places.
By using DNA sequencing software and using comparative DNA alignment programs, scientists can piece together where the differences and similarities align and the percentage of identical DNA between two species. Another method of classifying these gene-swapping organisms is to alter the method of vertical genomics and shift to a new form of lateral genomics (Koonin et al. 2001). A method using vertical, linear genomics alone will not provide enough resources to clearly assign an organism to a taxonomic group. Also, scientists can look at gene loss over time as a method to group these organisms (Koonin et al. 2001). If scientists would rather stick with similarities to define a taxonomic group, the use of genomic instruments can provide a better picture of which genes are highly conserved between organisms of the same group (Doolittle 1999). Researchers have begun to employ this method as the means for best completing a phylogenetic tree. Using alignments of single copy genes conserved in the genome allows for scientists to achieve that vertical pattern of phylogeny that can be lost when focusing on the amount of transferred genes between groups (Lang et al. 2013).
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.
The creosote bush grasshopper has a simple body. It has a rounded head capsule which contains the compound eyes, chewing mouth parts, and the short thread-like antennae, which are always shorter than the rest of body (Estella, 2009). The middle thoracic segments and part of the abdomen are covered by a type of hard shield called a pronotum which extends from the first thoracic segment. The forewings are leathery but they are not used for flight. Instead, they protect the delicate hind wings. They also have long jumping hind legs, which enable them to leap well over 20 times their body length (Anonymous, 2015).
Introduction: Terrestrial isopods, also known as pill bugs, are comprised of a variety of different species and are known for their adaptability to different environments, which have certain wavelengths of light and sufficient water and nutrients to survive (Danielson et. al. 1976). They are usually found in moist, dark areas because they are extremely vulnerable to dehydration and need a sufficient amount of water to survive (Wagler et. al. 2013).
The most prominent fossils in the Crato Formation are the insects that are preserved. One example of an insect that has been recently found is the Araripenymphes seldeni (as seen in figure 3), an extinct species of lacewing (Myskowiak et al., 2016). The taphonomic classification of A.seldini is: Nymphidae Family Neuroptera Order, and Insecta Class (Myskowiak et al., 2016). This particular species shows sexual dimorphism, a difference in characteristics beyond the sexual organs (Clarkson, 1998). In particular, differences in the wing colouration and wing lengths (Myskowiak et al.,
Kid’s U Presents… Black Widow- Amazing Pictures and Facts about the black widow spider. Have your children ever wondered what a black widow looks like? What does a black widow eat?
Echinoderms, named for their spiny surfaces, include an array of 70000 species which are all mostly sessile marine mammals, that lack overall body segments (Myers, n.d.). Nonetheless, typically ranging from 1cm-2m, they are known to have an extoskelton constructed from hard plates just beneath the skin, and possess a water vascular system- which their tube feet are connected to (Myers, n.d.). Additionally, they are known to show bilateral symmetry as larvae, but then after they metamorphose, feature a strong appearance of radial symmetry (Myers, n.d.).
An international team of Scientists have discovered a new lineage of extinct plankton feeding sharks called pseudomegachasma. These sharks are said to have inhabited the warm oceans of nearly 100 million years ago. From data of newly collected fossil teeth, it is found that this new lineage of extinct sharks is very similar to the modern-day plankton eating megamouth shark. Lead Author professor Kenshu Shimada also states that these sharks would have evolved independent of the four known modern-day planktivorous cartilaginous fishes. These consist of the megamouth shark, basking shark, whale sharks, and manta rays. This discovery of the new lineage of extinct vertebrates is what makes this article completely relevant to the topic of week fourteen.
When using morphology to determine the species included in the genus Homo, characteristics such as the bony labyrinth and limb proportions can be considered, which can be a strong indicator of the species posture and main mode of locomotion. The bony labyrinth may be an appropriate structure to study because data is obtained from the crania which is more definitively assigned to species than isolated limb bones. However, evidence
Phylum Echinodermata consists of organisms that are invertebrate, thus they lack a backbone and have a simplistic circulatory system, but their respiratory system is versatile with the variety of organs, such as gills (as seen the sea star), tracheas, skin, and book lungs (Hsia 2013). Since Phylum Chordata is more complex than Echinodermata, Chordata has a variety of organs in their organ systems, such as the skin and muscles in the circulatory and respiratory systems (Shu 2003). In order to completely analyze the circulatory and respiratory systems in the phylums Echinodermata and Chordata, organism from each phylum can be thoroughly dissected to expose entire organs and to allow manipulation of the organs. To execute this experiment, several