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
The terrestrial runoff spawned at around the time of major storms that wash large amounts of nutrients promotes plankton to blooms, which increase the food for many animals including Crown-of-Thorns Starfish larvae. The Great Barrier Reef receives runoff from 35 major catchments, which drain 424,000 square kilometres of coastal Queensland (Reefplan.qld.gov.au, 2012). Attacking the Crown of Thorns Starfish problem is through an integrated pest management approach that may be achieved by improving water quality as the long-term benefits to the health of the Great Barrier Reef.
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.
The gonads are the male and female reproductive organs, the testes (males) and ovaries (females). The testes and ovaries produce androgens (testosterone) and estrogens, these hormones affect aggressiveness, mood, and sexual interest and behavior. Higher levels of these hormones have been shown to promote aggressiveness in both sexes (Morris and Maisto, 2002).
Female Leafy Sea Dragons lay up to 250 bright pink eggs. Then, she deposits the eggs to the male’s tail with her ovipositor. Finally, the eggs attach to the brood patch which supplies the babies with oxygen.
They are carnivores, but are prey to Loggerhead turtles, certain slugs, and the blanket octopus. Although, the Nomeus Gronovii, a type of small fish, lives in the tentacles of the Man of War to feed off of it and for protection. In groups of 1,000 or more, they travel by the winds and currents for movement through the warm waters. For their life cycle, they reproduce in the fall and the eggs and sperm are fertilized by external fertilization. They are hermaphrodites that contain both eggs and sperm. After that stage, they transform into larva, the change into a polyp, and then they detach themselves from the budding polyp to become the creatures that there are today. Also during this process, Gonozooids make individual cells from asexual division which will contain all three parts, (the gastroderm, epidermis, and the mesoglea). Due to this reproduction, they are not endangered; but they are difficult to study since they do not do well in captivity. Also, they are difficult to find and study since the colors on their bodies absorb UV light that would normally kill most animals, but on their bodies, it acts as a sunscreen. Thus, allowing for them to survive.
With sperm, each cell goes through meiosis to produce four sperm cells. During oogenesis a oogonium cell undergoes mitosis to produce primary oocytes. It differs from sperm formation because it is a stop-start process. It also divides the cell unequally and one primary oogonium cell produces one active cell in contrast to sperm.
Those tentacles have sucker-pads that help bring in the prey into the sharp beak the cuttlefish has. As the cuttlefish, being a carnivorous creature, it usually feeds on small crustaceans such as shrimp and crab. They also hunt on various types of fish along with others of its kind. During mating season male cuttlefish will change their body color to attracts a female cuttlefish. When the male cuttlefish is wooing a lady, he will often “cheat” by making female patterns on one side of the body while the other side the one facing the females shows off male patterns, this fools other males into thinking there just seeing a couple of females but that means more opportunity of the cheater cuttlefish to mate before they are discovered by other males. Female cuttlefish lay around 200 eggs and shortly die afterwards. In the cuttlefish they have this thing called the cuttlebone, but it is not actually a bone, but rather the internal shell of the cuttlefish, the cuttlebone is filled with gasses that help control buoyancy in the water. For years people have harvest and used the bones for many purposes. The usage of the cuttlebone is widely recognized as supplements and exercise toys for
Across the entire North America pacific, millions of sea star have died of a disease known as Sea Star Wasting Syndrome. The virus itself has been linked to rising sea temperatures in accordance with climate change, and was responsible for the biggest mass mortality of asteroid species in history. There have been over 20 species affected, including Pisaster giganteus, a crucial keystone species. In the years since the outbreak of the virus in 2013, researchers have been observing the effect on the populations to determine the impact on the ecosystem as well as the possibility of sea star populations recovering.
As researched, earthworms are known as hermaphrodites, which are defined as an animal having both male and female sex organs or other sexual characteristics, either abnormally or (in the case of some organisms) as the natural condition (Dictionary). During the earthworm lab, I discovered that earthworms have both seminal vesicles and seminal receptacles. Holding sperm after cross-fertilization has occurred is the seminal receptacles for females only. Seminal vesicles produce and release sperm and are well known as the male reproductive organs. Gizzards are responsible for mechanical digestion and grinding up the food for earthworms (Earthworm dissection video). On the other hand, for male crayfish to make sperm they must contain testes, unlike the females they
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
“The meeting of two eternities, the past and future….is precisely the present moment.” Infante D. Henrique of Portugal, better know as Prince Henry the Navigator, was born in Portugal in 1394. During his time alive, Henry was a big supporter of multiple sea voyages, mapping the west African coast along the way. Henry not only encouraged sailors in his homeland, but was also able to spread encouragement to other sea explorers for years to come. Without Henry the Navigator, Europe would lose one of its key players in the Age of Exploration, stopping Europe’s further development for some time.
Robert Vrijenhoek observed these processes in topminnows. The ponds where these fish live include fish that reproduce sexually and fish that produce assexually. This population is affected by parasites that cause black-spot disease. He found that more of the assexual fish were afftected than the sexual fish. This is because when the parasites were able to effeccrively attack one assexual fish, they could attack all of them as they are clones. This didn’t apply to sexually producing fish as they were all different (“The Red Queen” 2001).
the sperm are categorized as masculine and feminine. Finally, it seems that the end goal of
Ernest Hemingway was an extraordinary individual. There was a lot more to his life than most readers know about. His writing was influenced by the lifestyle that he led. Hemingway was an adventurous person that liked to live life to its fullest. Just like everyone, he made decisions that were both good and bad, and his decisions and actions shaped his writing style. Hemmingway found a great deal of success and his career was topped off with him being awarded the Pulitzer Prize and the Nobel Prize in Literature (The Biography Channel). This is what made him into the writer that he was.
Article: de Beera, M., and Masona, R. B. (2009, May 2). Using a blended approach to facilitate postgraduate supervision. Innovations in Education and Teaching International, 46 (2), 213 226.