COOL SCIENCE JUNK!

Hello! My name is Lacey and I am an enthusiastic Marine Biology Major at the University of West Florida. This is an account of my Biology II Laboratory for the Spring semester of 2017. Enjoy nerds!

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Placoid Scale

Placoid scales are the tiny tough scales that cover the skin of sharks, rays, and other elasmobranchs. Even though placoid scales are similar to the scales of bony fish, they are modified teeth and are covered with a hard enamel. They grow out of the dermis layer and this is why they are called dermal denticles.

Take a look at this cool infographic on scale types.

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Cycloid Fish Scale

Cycloid (circular) scales have a smooth texture and are uniform, with a smooth outer edge or margin. They are most common on higher-order bony fish with soft fin rays, such as salmon and carp. As the fish grow, scales are added in concentric layers. The scales are arranged so as to overlap in a head-to-tail configuration, like roof tiles, allowing a smoother flow of water over the body and thereby reducing drag.

Take a look at this cool infographic on scale types.

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Ctenoid Fish Scale

Ctenoid (toothed) scales have small teeth along their outer edges. They are usually found on fishes with spiny fin rays, such as the perch-like fishes. The scales have a rough texture with a toothed outer or posterior edge featuring tiny teeth called ctenii. As the fish grow, scales are added in concentric layers. The scales are arranged so as to overlap in a head-to-tail configuration, like roof tiles, allowing a smoother flow of water over the body and thereby reducing drag.

Take a look at this cool infographic on scale types.

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Ganoid Fish Scale

Ganoid scales are found in the sturgeons, paddlefishes, gars, bowfin, and bichirs. Most are diamond-shaped and connected by peg-and-socket joints. They are usually thick and have a minimal amount of overlap as compared to other scales.

Take a look at this cool infographic on scale types.

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Infraphylum Gnathostomata

Gnathostomes are known as the jawed vertebrates. They include sharks (and their relatives), ray-finned fish, lobe-finned fish, amphibians, reptiles, birds, and mammals. Organisms classified as gnathostomes have hinged jaws. They also show development of the teeth and start to show mineralization in their teeth and bones.

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Infraphylum Agnatha

Agnathans are a group of jawless fishes that include Myxini (hagfish) and Petromyzontidae (lampreys). Pictured above are Petromyzontidae, also known as lampreys.  The name "lamprey" is derived from Latin meaning "stone licker." The most well known lamprey species are a parasitic and feed by boring into the flesh of other fish to suck their blood. However there are a some species of lamprey that non-parasitic.

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Subphylum Vertebrata

Vertebrates include fishes, amphibians, reptiles, birds, and mammals. They are defined by the presence of vertebrae, segmented bones which enclose the spinal chord. Vertebrates also have elaborate skulls that encloses and protects more developed brains. 

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Hey!! I find marine biology super cool, but everyone tells me I won't get a stable salary from it. Any advice?

Hello!! So sorry about the late reply. Anyway, I understand your struggle with people constantly wondering about the financial stability of a scientific career. For some scientific careers, especially those relating to marine biology, it is hard to estimate earnings because there are so many different pathways to chose from. What I mean by this is that your could take your passion for the ocean and work in many different places doing vastly different things. For example, you could work at a university teaching students and researching, or you could work in an aquarium taking care of animals, or you could work at a private research company/consulting firm. Each of these paths have different salary ranges. Another thing about marine biology is that it is a highly competitive field (and may be one of the reasons why people see this career as less stable than others.) 

I will not lie to you and say that marine biology careers are the most lucrative option out there; however, this does not mean that you cannot make a stable salary! Marine science careers, in my opinion, are more about your passion and drive to discover, educate, or conserve. So my main advice would be to continue doing what you love. If you are passionate about marine biology you will find that the advantages far outweigh the few downfalls. Also if you are not quiet sure if a career in marine sciences is your calling then you still have plenty of time to figure it out. Try interning or volunteering where you may be able to earn some experience.

Sorry about my rambling!! I hope it helped at least. 

I highly suggest you check out SciAll.org’s YouTube channel. He has some cool videos. The video I linked here may help to answer your question.

Thank you so much and have a Thresher Shark for the road!!

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Hello All!!!

I am so sorry about the long hiatus and I promise that this blog is not dead. Finals hit hard and I decided I needed to take a break for the summer to catch up with everything else in my life. Anyway, I still have a few photos from my last labs that I will begin posting soon (if not by the end of this month then definitely by the beginning of August). Thank you all and take a look at the beautiful whale shark! (The largest fish in the world!!!)

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Subphylum Cephalochordata

Subphylum Cephalochordata includes lancelets. This subphylum, along with subphylum Urochordata, is informally classified under protochordates. Protochordates are “primitive” chordates that are not vertebrates. Lancelets are marine filter feeders and show all five chordate characteristics throughout their life. These animals have finger-like projections near their mouth called cirri. These structures act as a coarse filter to screen out particles too large to consume. 

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Subphylum Urochordata

Subphylum Urochordata (also called Tunicata) includes tunicates, salps, and larvaceans. This subphylum, along with subphylum Cephalochordata, is informally classified under protochordates. Protochordates are “primitive” chordates that are not vertebrates. Most adult tunicates are sessile and do not show chordate characteristics. However tunicates have a free-swimming larval stage that exhibits all chordate characteristics. Tunicates get their name from the outer covering, called a tunic, which cloaks their body.

The first two photos show pictures of tunicate larva. The next three photos show pictures of adult tunicates.

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Phylum Chordata

Chordates are defined by five distinct characteristics:

1) The presence of a notochord. A notochord is a flexible rod that is the main axial supporting structure in all embryo and some adult chordate animals.

2) The presence of a dorsal, hollow nerve chord. The nerve chord is located dorsal to the notochord.

3) The pharyngeal apparatus. This embryonic structure consists of pharyngeal arches, pharyngeal pouches, and pharyngeal groves. These structures are used for feeding and respiration. In lower chordates parts of this structure develop into gill slits that are used to filter water and collect food particles. More derived chordates have modified pharyngeal arches into structures of the head and neck. (A common misconception is that human embryos have gill slits. This is incorrect terminology. Human embryos have the pharyngeal apparatus that do not actually develop into slits.)

4) The presence of a post-anal tail. This structure is an extension of the notochord and nerve chord past the anus.

5) The presence of the endostyle. This structure is an elongated groove in the pharynx floor of protochordates (”primitive chordates” that are not vertebrates) that develops into thyroid gland in chordates. These structures play a role in regulating metabolism.

It is important to note that all five traits are present throughout the development of a chordate; however, not all five traits may be present at the same time. This phylum includes the subphylum Urochordata, subphylum Cephalochordata, and subphylum Vertebrata. 

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Phylum Enchinodermata - Class Holothuroidea

Members of the Phylum Enchinodermata have a very unique system called the water vascular system.  The water vascular system is a hydraulic system used for locomotion, food and waste transportation, and respiration. The madroporite is a pore that acts as the opening for water to enter the water vascular system.

Class holothuroidea includes sea cucumbers. Sea cucumber’s oral-aboral axis is elongated with the mouth at the oral pore and the anus at the aboral pore. The madroporite is located inside of the sea cucumber in its coelom. A significant internal structure is the respiratory tree. The respiratory tree is a highly branched internal structure used for gas exchange and excretory function. As a defense mechanism, some cucumbers will expel their internal contents out of their cloaca in a process called evisceration. These structures are regenerate within the following weeks.

Take a look at this cool video on sea pigs (a type of sea cucumber)!

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Phylum Enchinodermata - Class Enchinoidea

Members of the Phylum Enchinodermata have a very unique system called the water vascular system.  The water vascular system is a hydraulic system used for locomotion, food and waste transportation, and respiration. The madroporite is a pore that acts as the opening for water to enter the water vascular system. The water travels down the stone canal to the centralized ring canal. From the ring canal the water travels to the edges of the organism using radial canals. From the radial canals water goes through lateral canals that connect to bulb-like sacks called ampulla. Each ampulla connect to a tube foot which is used for locomotion. Water pools in the ampulla and contractions of this small sack either retract or extend the tube feet.

Class Enchinoidea includes sea urchins, sand dollars, and sea biscuits. Sea urchins are considered regular because of their round shape. Sand dollars and sea biscuits are considered irregular because of their flattened shape. The madroporite is located in the center of the aboral surface. This class also has a unique structure called an Aristotle’s lantern. This structure is shown in the second photo and allows for increased mobility and control of the teeth.

The first photo shows a sea urchin without spines. The bottom left photo shows a picture of a sea biscuit and the bottom right photo shows a picture of some sand dollars.

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Phylum Enchinodermata - Class Ophiurodea

Members of the Phylum Enchinodermata have a very unique system called the water vascular system.  The water vascular system is a hydraulic system used for locomotion, food and waste transportation, and respiration. The madroporite is a pore that acts as the opening for water to enter the water vascular system. The water travels down the stone canal to the centralized ring canal. From the ring canal the water travels to the edges of the organism using radial canals. From the radial canals water goes through lateral canals that connect to bulb-like sacks called ampulla. Each ampulla connect to a tube foot which is used for locomotion. Water pools in the ampulla and contractions of this small sack either retract or extend the tube feet.

Class Ophiurodea includes brittle stars. Brittle stars have a central disk that is clearly distinguishable from the arms. Brittle stars’ madroporite is located on the oral side (the side with the mouth).

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Phylum Enchinodermata - Class Asteroidea

Members of the Phylum Enchinodermata have a very unique system called the water vascular system.  The water vascular system is a hydraulic system used for locomotion, food and waste transportation, and respiration. The madroporite is a pore that acts as the opening for water to enter the water vascular system. The water travels down the stone canal to the centralized ring canal. From the ring canal the water travels to the edges of the organism using radial canals. From the radial canals water goes through lateral canals that connect to bulb-like sacks called ampulla. Each ampulla connect to a tube foot which is used for locomotion. Water pools in the ampulla and contractions of this small sack either retract or extend the tube feet.

Class Asteroidea includes true sea stars or starfish. True starfish have a central disk that is non-discrete from the five arms. True starfish’s madroporite is located on the aboral side (the side opposite the mouth on the bottom). In the second photo you can clearly make out the madroporite (the light pore on the left of the starfish). 

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Phylum Arthropoda - Subphylum Hexapoda

The most notable characteristic of the phylum Arthropoda is the presence of jointed appendages. A second major characteristic is an exoskeleton. Unlike the cuticles seen in nematodes and tardigrades, the exoskeleton of an arthropod is made primarily of chitin and can be reinforced by the process of biomineralization (the addition of tough minerals and hardened proteins). The anatomy of arthropods divides the body into three main tagma. These tagma include the head, thorax, and the abdomen. In some cases two or more tagma can be fused. When the head and thorax are fused it forms a cephalothorax. When the thorax and the abdomen are fused it is called a trunk.

Subphylum Hexapoda (”six-footed”) contains insects. Their anatomy contains all three segments: head, thorax, and abdomen. Hexapods have one pair of mandibles, one pair of antennae, and one pair of maxillae on their head. Additionally they have lips called the labrum and labium. This subphylum is characterized by its three pairs of legs. Typically insects have two pairs of wings. Hexapods, like myriapods, use spiracles (holes along the side of the exoskeleton) and tracheal tubes (tubes that allow oxygen transportation around the body) for respiration.