Parthenogenesis: The Case With Marbled Crayfish

Breeding: Blue buttons are hermaphrodites (i.e. both male and female). The specialised reproductive polyps release both eggs and sperm into the water. When the eggs have been fertilised by the sperm, they develop into larvae that subsequently metamorphose into individual polyps. A Blue Button colony forms when one polyp divides to form new types of polyps which become specialised for different functions.

Lake Malawi’s cichlid male population of fish are tested on their ability to build bowers to attract the female population. Altering this extended phenotype, or ability to build bowers resulted in no change of mating, but males that built successful bowers showed to

Charlene Forest is an associate professor in the Biology department at Brooklyn College, who dedicates her research in to trying to understand the mechanism behind the process of fertilization in algae, as well as what controls expression of gamete-specific genes. To do so, she must understand how sperm and egg gametes first recognize and then fuse with each other. Thus, in order to find what causes the fusion of these gametes, Forest’s lab is cloning genes that prevent the fusion of sperm and egg gametes. She hopes that her research on the fertilization process in algae will help understand the fertilization process in other organisms, particularly humans.

Starfish and crayfish are both invertebrates, but they have many differences. Last week,  our class did a dissection on each and learned more about them. This research paper will explain some differences between the two that were learned during dissections and by doing outside research.

Throughout decades, sexual selection has been acknowledged in the explanation of evolutionary patterns. With research, we have had the opportunity to study species of animals like the Syngnathidae family. Animals that are included in this category include pipefish, seahorses, and sea dragons. This species is known for their sex role reversal, meaning that the male fertilizes and carries the eggs during incubation after the female has laid them. When we look more specifically at the pipefish, it is found that males are left with most of the parenting and care for the offspring. As the male carries its eggs, it supplies them with nutrients and oxygen through the placenta. During pipefish copulation, the female transfers her eggs through a small

fish with higher levels were found to change sex more rapidly. It was also found that the GnRH levels were significantly higher in the male brains, but there was not a significant level of the hormone in the gonads. Also, there was no significant change in the females who were given the injections. The findings support the researchers hypothesis that the GnRH hormone plays an important role in the development of cinnamon clownfish, specifically in males. Another interesting thing that the researchers found was that the chromosomes of the fish do not change, even if they do undergo a sex change. Fi the fish was originally made and changes to female then it will still have the genetic makeup of XY

Unlike the fertilization of mud-puppies, the fertilization of perch fish is external. Usually, a female will release many of her eggs into the water and the male will release the sperm, or milt, over the eggs. This process is known as spawning. Just like the development of the mud-puppies, the development of the yellow perch is indirect and involved a larval stage and a juvenile stage. (Perca Flavescens: American Perch)

Both Xenopus and Zebrafish are excellent model organisms in the study of development. They can both be generated in the lab at relatively low cost and development of the embryos can be observed within a relatively short time frame. The eggs themselves are also very easy to observe due to their transparency. Xenopus can be generated through in vitro fertilisation or natural mating with an optimal temperature of 23°C (Xenbase.org 2014). Zebrafish similarly can be generated in relatively large sizes, by maintaining them on long day photoperiods of about 14 hours of light and 10 hours of dark with their development, once fertilized and incubated between 26-28°C, hatching between 3-4 days (Bradford and Sun 1994).

Imagine not having air conditioning, water, the ability to cook your food, or even to charge your cell phones. Now imagine that all of this was caused by a “brainless, jelly like creature with tentacles” known as the jellyfish. Jellyfish are affecting fisheries, power plants, and politics in many places over the world leading to scientists researching this creature to find out why.

Mice and rats have been the most common model organism that used for research. Recently, the zebrafish (Danio rerio) has emerged as one of the most popular animal model in different area of research such as developmental biology, genetics, and pharmacology (Liu et al., 2010; Eisen, 1996). Compared with other animal models, the zebrafish has numerous advantages that make them valuable as an animal model. The zebrafish has a small size (adult ~ 1- 1.5 inches long) and short generation time (about 3 months). In ideal condition, a female zebrafish can produce 100-200 eggs at weekly intervals, which can allow performing assays that required a large number of subjects. The zebrafish embryos undergo rapid external developmental within 2-4 days, and

While majority of the echinoderm starfish are either male or female, certain starfish undergo a process known as sequential hermaphroditism. This means while certain starfish are born all male, certain males become female over time, as they stop producing sperm and begin producing eggs. In addition, starfish can reproduce both sexually and asexually, either by releasing sex cells into the water, by fission, or autonomy of arms, meaning starfish can essentially split into two. The starfish contains two gonads in each arm, known as ovotestis. Their purpose is to carry out the process of sexual reproduction. This type of gonad is seen in both genders of starfish, producing sperm for the males while producing eggs for the female. Starfish eggs

Asymmetry in decapods has been a focus of an on and off interest as observed by Oppenheimer (1974) in McLaughlin, et al.,(2004) among carcinologist as decapod asymmetry has been a focus of importance for nearly a century (Przibram 1905; Emmel 1908), then interest plummeted and risen again. Asymmetry in abdomen shape between male and female crab have been observed among Ranina ranina as early as the instar 1 larval stage (Minagawa, 1993) rendering this character to be sexually dimorphic among these crabs. Posteriorly attached to the carapace, these structure provides adherence for eggs for ovigerous females. What makes the R. ranina abdomen unique among crab species is it attachment to the carapace. While in most crabs, abdomen are folded towards the ventral aspect of the crab, in R. ranina, it is partially extended away from the ventral aspect that it looks like a tail instead of as an abdomen. The abdomen also participates in the digging activity of the crab (Faulks, 2006). Asymmetry in pleopods was observed among paguroids as an offshoot of the type of shells they are inhabiting. Asymmetry in shapes are often associated with the frequent use of a particular character such as handedness or constant use (McLaughlin, et

Although the worlds of Buenos Aires and La Plata are conveyed throughout The Fish Child, there are also references that do not reflect the literal metropolis. However, these imaginary geographies still allude to spatial divisions created through cultural, social and economic divides within Buenos Aires:

Owing to the optical transparency of the larvae, evolutionary similarity to humans, and large numbers of animals that can be employed in experiments, Zebrafish are a suitable model for studying the development and progression of glioblastoma. Glioblastoma multiforme is the most common malignant primary brain cancer with a median survival of 15 months after an aggressive treatment. Glioblastoma evade recognition and destruction from the immune system through changes in the biochemistry in the tumour vicinity. Moreover, studies until now recognize that direct interactions with cells from the immune system, such as microglia/macrophages and neutrophils promote cancer growth. The dynamics of tumour-immune-system-cells can be observed observed in

One of the major classes of rotifers can have two modes of reproduction. There are two kinds of females. During female parthenogenesis, amictic females produce diploid eggs (2n) that are not fertilized. All of these eggs develop and hatch into amictic females. Change in environmental conditions allows the females to go through another sexual reproduction that produces mictic males and amictic females. There are minor morphological differences between the two polymorphic forms. Mictic females produce haploid eggs (n). When haploid eggs are fertilized, they develop into amictic females. The unfertilized mictic eggs hatch out larvae that develop into haploid males. This is known as haplodiploidy, a mechanism of sex determination. Males are produced