ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

Fascinating Creatures of the World - Squids

Updated on December 24, 2014
Source

Where do squids come from?

From the past to the present, squids have evolved into a complex organism capable of living in a variety of environments. Although there are three hundred known species of squid in the world today, each species contains similar structures and organs that help it survive and reproduce (information).

Squids belong to the phylum mollusca, which includes:

  • snails
  • clams
  • octopi
  • chiton
  • many others

Whereas these other creatures evolved to different classes like gastropoda for snails and bivalvia for clams, squids and octopi are part of the class cephalopoda. The prefix cephalo means "head" and the suffix poda means "foot", but these organisms do not have feet at all.

The diagram above shows the location of all external features of the common squid.
The diagram above shows the location of all external features of the common squid. | Source

Squids Swimming

How do Squids Move?

Instead of using a foot like their relatives, squids move by jet propulsion via their long, powerful tentacles. Let's explore this more closely:

  1. Water is taken in as the mantle, which is everything visible behind the head, opens. The outer body wall and all fins, head, etc are part of the mantle.
  2. As it closes, water is expelled through the siphon, which is a nozzle like structure right below the eyes. The squid can swim in any direction by bending the siphon, but it usually swims backwards (Animal Planet). Some squid can propel themselves up to twenty-five body lengths per second, which helps it stay away from predators or attack and capture its prey.
  3. The expulsion of water propels the squid in the direction it desires.


http://www.coralreefphotos.com/wp-content/uploads/2010/02/Caribbean-Squid-Beak-457x303.jpg
http://www.coralreefphotos.com/wp-content/uploads/2010/02/Caribbean-Squid-Beak-457x303.jpg

What and How do Squids Eat?

Speaking of prey, what common foods might be tasty and exciting for the squid?

Most squids tend to feed on small fish, crabs, and shrimp. Sometimes when food is scarce, squids will eat other squids that are smaller or weaker than them, but this is not very common. However, squid cannibalism is not unheard of in the event of a food shortage.

Using a small beak that serves the same function as a mouth, squid can easily pierce their prey and shred it into small pieces that are easier to digest. They initially capture their prey using their tentacles. These long tentacles have small circular rings that hold the prey still and capture them using suction so the squid's meal cannot escape.


What were to happen to a population of squid if a species or predator were to be introduced?

Today's squid are a primary meal for predators like sharks (blue shark), but what would happen to squids if a new predator - one that relied on speed and eyesight - were to inhabit a squid's environment? Natural selection would take its course, where some squid with certain traits would be more likely to survive than others, but what traits would be valuable in these circumstances?

Say that a species of squid inhabits a shallow, rocky portion of the ocean. A lot of sunlight comes through the water, making the squid rely on the plants and rocks for protection against predators that live out in the open water. Originally this species of squid range from a muddy brown color to a cool grey, with the rocks it lives next to also a cool grey. These squid are naturally brown to grey, and the rocks it lives near are also grey.



Grey Squid
Grey Squid | Source
Brown Squid
Brown Squid | Source

What new predator would shape the future evolution of squids?

The predator is a new species of shark that are not native to this area. The shark can easily see squid that cannot blend in with their environment, therefore...

  1. They are more likely to attack the brown squids instead of the grey ones.
  2. Over time, the grey squids become a large majority because of the lack of the brown gene present in this species due to predation.
  3. Grey squids have a better sense of camouflage by making it more difficult for the sharks to see them against their environment.
  4. This species would likely become more grey over a long period of time.


Could size be an advantage or disadvantage?

Smaller squids could also have an advantage over larger squids.

Squids with long tentacles could be easier to capture than squids with short tentacles.

However, short tentacles make it more difficult for a squid to capture its prey. If the squids have a stable food source or something easy to capture, then shorter tentacles would have an advantage. If the squid were easily preyed upon and had trouble finding food, then the species would likely not survive in the shallow, rocky area unless it could fit in the rocks to hide from the sharks.

This small squid is roughly the size of a human finger.
This small squid is roughly the size of a human finger. | Source
This Giant Squid is one of the largest ever captured.
This Giant Squid is one of the largest ever captured. | Source
The beak is the "mouth" of the squid. It aids in crunching hard shells and eating food.
The beak is the "mouth" of the squid. It aids in crunching hard shells and eating food. | Source

What about beaks?

Squids already have sharp beaks that capture and shred prey, but what would happen when a squid must change from a primarily offensive to a primarily defensive organism? Squids with larger beaks would have a higher chance of survival because larger beaks can do more damage to prey and predators. If the size is not a factor, then a squid with a serrated beak or a sharper one would outlive a squid with a smaller, ordinary beak. These squid would survive and reproduce, allowing more squid with well equipped beaks into the population.

What is the coolest part of a squid?

See results

Comments

    0 of 8192 characters used
    Post Comment

    No comments yet.

    working

    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, hubpages.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

    For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: https://hubpages.com/privacy-policy#gdpr

    Show Details
    Necessary
    HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
    LoginThis is necessary to sign in to the HubPages Service.
    Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
    AkismetThis is used to detect comment spam. (Privacy Policy)
    HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
    HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
    Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
    CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
    Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
    Features
    Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
    Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
    Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
    Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
    Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
    VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
    PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
    Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
    MavenThis supports the Maven widget and search functionality. (Privacy Policy)
    Marketing
    Google AdSenseThis is an ad network. (Privacy Policy)
    Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
    Index ExchangeThis is an ad network. (Privacy Policy)
    SovrnThis is an ad network. (Privacy Policy)
    Facebook AdsThis is an ad network. (Privacy Policy)
    Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
    AppNexusThis is an ad network. (Privacy Policy)
    OpenxThis is an ad network. (Privacy Policy)
    Rubicon ProjectThis is an ad network. (Privacy Policy)
    TripleLiftThis is an ad network. (Privacy Policy)
    Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
    Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
    Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
    Statistics
    Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
    ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
    Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)