Week Eight: The different morphology specialisations available in Marine dwelling species and how they function

This week’s blog is on Marine organisms, marine animals have had to become some of the most specialised animals on earth because they have a lot of constraints. Lifestyle in salt water poses a great many challenges, some of these are: being able to breathe underwater, density and propulsion, being able to swim through the water, water temperature, getting freshwater or processing salt water, being able to see, communicate and search for food (Vermeij 1978)

One of the first things that is common to almost all marine forms of life is the streamlined “tear drop” body shape that they have developed. This has been developed for the ease of movement and to lessen drag in the water, this minimises the energy expelled whilst swimming. Next is the method of propulsion, they need to be able to move and here are a few different kinds of water locomotion; Jellyfish use “free swimming” where they pulsate their bell shaped mantle in order to create propulsion, otherwise they carelessly glide through the water with little effort. Fish use wave like movements of the body and tail to propel themselves through the water, alternatively squid travel by something called “jet propulsion” where they fill their inner mantle cavity with water and the quickly propel the water out which moves them equally in the opposite direction (Colin & Costello 2002).

Dolphins are a predator (Figure 1) and as such have a need for strong locomotory capacity (Seibel & Drazen 2007) they are also specialised that they have developed a type of sight called “echolocation” where they give out calls and listen for the echo to give them a dimensional image of their surroundings this is often used for navigation and for finding food. Dolphins have also got a clever adaptation for breathing in that they have a blowhole on their head which is muscular and can open at the surface to allow in air.

Figure 1. Dolphin (Tursiops)

Viewed 27/04/17: http://bit.ly/2oLP9u8

References:

Munday, P. 2004, Habitat loss, resource specialization, and extinction on coral reefs, Global Change Biology, Vol 10, issue 10, pp 1642–1647

Gaillard, J. Festa-Bianchet, M. Yoccoz, N. Loison, A. and Toigo, C. 2000, Temporal Variation in Fitness Components and population Dynamics of Large herbivores, Annual Review of Ecology and Systematics, Vol 31, pp 367-393

Grant, R. Grant, P. 1996, High Survival of Darwin’s Finch Hybrids: Effects of Beak Morphology and Diets, Ecology: Ecological Society of America, Vol 77, issue 2, pp 500-509