The Southeastern Pennsylvania Transportation Authority (SEPTA) provides public transportation into and within Philadelphia as well as serving the surrounding Bucks, Chester, Delaware and Montgomery counties.
What is the purpose of the septa in the Nautilus?
Septa (singular septum) are thin walls or partitions between the internal chambers (camerae) of the shell of a cephalopod, namely nautiloids or ammonoids. As the creature grows, its body moves forward in the shell to a new living chamber, secreting septa behind it.
What is the function of the Siphuncle in cephalopods?
The siphuncle is used primarily in emptying water from new chambers as the shell grows. Essentially what happens is the cephalopod increases the saltiness of the blood in the siphuncle, and the water moves from the more dilute chamber into the blood through osmosis.
What is the name of the reduced shell in a squid?
The shell of a cephalopod is normally tube- or cone-shaped with many dividers. These dividers are called septa, and they partition the inside of the shell into chambers.
What is septum?
Definition of septum
: a dividing wall or membrane especially between bodily spaces or masses of soft tissue — compare dissepiment.
Is SEPTA safe at night?
Yes SEPTA regional rail is safe at night.
Do cephalopods have a radula?
All living cephalopods have a two-part beak; most have a radula, although it is reduced in most octopus and absent altogether in Spirula. They feed by capturing prey with their tentacles, drawing it into their mouth and taking bites from it.
Do Belemnites have sutures?
They are most commonly found broken in half or several pieces, usually along suture lines. Individual chambers are sometimes referred to as “stone buffaloes” (due to their shapes). Belemnites first appeared in the Lower Jurassic Period and went extinct by the end of the Cretaceous.
How old are cephalopod fossils?
When did they live? The oldest shelled cephalopods appeared towards the end of the Cambrian Period (about 500 million years ago) and some are still alive today. Ammonites lived in the Jurassic and Cretaceous periods (about 200 million to 65 million years ago) and disappeared at a major extinction event.
What does siphuncle mean?
Definition of siphuncle
1a : a membranous tubular extension of the mantle which runs through the partitions of the chambers to the apex of a shelled cephalopod : siphon. b : the shelly structures that are usually funnel-shaped or tubular processes of the septa and that ensheathe and support the cephalopod siphuncle.
What is the evolutionary trend in cephalopods?
Cephalopods were thought to have “undoubtedly” arisen from within the tryblidiid monoplacophoran clade. … However genetic studies suggest that they are more basal, forming a sister group to the Scaphopoda but otherwise basal to all other major mollusc classes.
What is the function of the ink sac?
With the exception of nocturnal and very deep water cephalopods, all Coleoidea (squid, octopus and cuttlefish) which dwell in light conditions have an ink sac, which can be used to expel a cloud of dark ink in order to confuse predators.
What makes a cephalopod a cephalopod?
Cephalopod literally means “head foot” in Greek, a reference to the way the cephalopod’s head connects to its many arms. The basic cephalopod body plan includes two eyes, a mantle, a funnel (also called a siphon), and at least eight arms.
Are cephalopods hermaphrodites?
Cephalopods are gonochoristic molluscs that show no hermaphroditism and the animals never change sex. Their main sexual dimorphism is the presence of a hectocotylized arm in males, which transfers the spermatophores to the female.
What is a cephalopod funnel?
The funnel–mantle locking apparatus is a structure found in many cephalopods that connects the mantle and hyponome (funnel) and restricts their movement relative to each other. It consists of two interlocking components: one located on the mantle (often fibrous) and the other on the funnel (often cartilaginous).
Why is it called septum?
Septum, heart: The septum of the heart is the dividing wall between the right and left sides of the heart. … The word “septum” is borrowed from the Latin “saeptum” meaning a “dividing wall or enclosure.”
Where is the septum?
The nasal septum is the cartilage and bone in your nose. The septum divides the nasal cavity (inside your nose) into a right and left side.
How many septum are there?
These two sides of the heart are separated by the inner wall called Septum. Septum have generally two parts i.e., Ventricular septum and Atrial septum. Ventricular septum forms a barrier between left and the right ventricle. Atrial septum forms a barrier between left and the right atrium.
Is the Philly subway safe?
To get from the Society Hill area to the UofP area, the best bet would be the Market-Frankford El/Subway line, which is perfectly safe. You can catch it at 2nd Street or 5th Street and take it westbound. 2. Re: How safe is SEPTA in general?
Are Philadelphia trains safe?
In general, while not always the cleanest, Philly public transit is safe, but yes there is the potential for incidents (as with almost any big city transit system. Use common sense while traveling (like do not flash jewelry while riding the subway at 2 AM) and you’ll be fine.
Is Suburban Station Safe?
SEPTA clears Suburban Station about 12:30 a.m. daily for security reasons and to give cleaning crews time to prepare for the morning commute. The station offers a warm, relatively safe refuge for people, many suffering from mental illness or addiction, who have nowhere else to go. But the space can become dirty.
What are the 4 groups of cephalopods?
Cephalopods are members of a class of marine animals that includes octopuses, squid, cuttlefish and nautiluses.
Why are cephalopods different to other molluscs?
The most obvious difference between most cephalopods and other mollusks is the apparent lack of a shell. … They are also the only cephalopods with four gills instead of two.) Cephalopods have a more developed nervous system than other mollusks. They also have very well developed eyesight that is used in finding prey.
What are the major cephalopod orders?
- †Order Belemnoidea (belemnites) …
- Order Sepioidea (cuttlefishes and bottle-tailed squids) …
- Order Teuthoidea (squids) …
- Order Vampyromorpha. …
- Order Octopoda (octopuses)
What is a cephalopod fossil?
Fossils of cephalopods (sef’-al-oh-pods) have been found in rocks of many ages, and numerous representatives are alive today. Squids, octopuses, cuttlefish, and the chambered nautilus are among the cephalopods living in modern seas. Cephalopods are the most advanced of all animals without backbones.
Is Ammonite a snail?
Molluscs are animals like mussels, clams, snails, slugs, cuttlefish and octopus. They include extinct creatures such as ammonites and belemnites. … Although most molluscs live in the sea, some are land dwellers such as the snail and slug. Mollusc fossils are usually well preserved because of their hard shell.
Are fossils worth any money?
Are fossils worth money? Fossils are potentially valuable items, although their worth depends on many factors. These include the age of the fossil, the size, the clarity, and the level of scientific value. There are many examples of dinosaur fossils that are worth staggeringly high sums of money.
Why are cephalopods so big?
Although some of these groups are known from scant fossil material, or in some cases a single specimen, it appears that gigantism has evolved a number of times in cephalopods. In living Architeuthis and Mesonychoteuthis species large size is thought to be an adaptation to the harsh environment of the ocean depths.
Why did cephalopods lose their shells?
The evolutionary pressures favored being nimble over being armored, and cephalopods started to lose their shells, according to Mr. Tanner. The adaptation allowed them to outcompete their shelled relatives for fast food, and they were able to better evade predators.
Why is it interesting that fossil cephalopods date back 500 million years?
Unlike the compound eyes that were common among Cambrian animals, probably had the camera-like structure that modern cephalopods use. … The sediment helped to preserve their bodies with such quality that 500 million years later, their position in the animal tree of life has suddenly become clearer.
What did cephalopods evolve from?
Cephalopods evolved during the Cambrian (∼530 Ma) from a monoplacophoran-like mollusc in which the conical, external shell was modified into a chambered buoyancy apparatus. During the mid-Palaeozoic (∼416 Ma) cephalopods diverged into nautiloids and the presently dominant coleoids.
Why are cephalopods generally considered the most advanced invertebrates?
Cephalopods have large, well-developed brains, and their brain-to-body mass ratio is the largest among the invertebrates, falling between that of endothermic and ectothermic vertebrates. The nervous system of cephalopods is the most complex of all invertebrates.
What is the habitat of a cephalopods?
Cephalopods live everywhere in the oceans: near the shore in shallow water; far from land in the open ocean; in the ocean’s dark middle depths (the planet’s largest habitat); and in the deep sea.
What is the dark brown ink squirted by octopuses called?
Cephalopod ink is a dark-coloured or luminous ink released into water by most species of cephalopod, usually as an escape mechanism. All cephalopods, with the exception of the Nautilidae and the Cirrina (deep-sea octopuses), are able to release ink.
How long does an ink sac stay on?
After you apply the first Saniderm bandage, we recommend leaving it on your new tattoo for between 8 to 24 hours. Everyone heals differently, and the length of time will vary depending on how much fluid your tattoo is weeping.
Where does the ink sac empty to?
Where does the ink sac empty into? Empties into the water jet. What is the function of the ink sac? To confuse its predators by releasing a dark fluid to cloud the water.
What’s the difference between a tentacle and an arm?
What’s the difference between an arm and a tentacle? Arms, like those on an octopus, have suction cups the entire length of the limb. Tentacles only have suction cups near the end of the limb. Some Cephalopods have arms, some have tentacles, and some have both!
What does a cephalopod look like?
Cephalopoda means “head foot” and this group has the most complex brain of any invertebrate. Cephalopods are characterized by a completely merged head and foot, with a ring of arms and/or tentacles surrounding the head. The arms, tentacles, and funnel are all derivatives of the foot. … All cephalopods are carnivorous.