On the Blue Ocean Floor

Ocypode quadrata

Oocypode quadrata, also known as ghost crabs, are small crabs (up to around 50mm) with square-shaped sand-coloured shells. They are commonly found in the inter-tidal zones. They breathe through moistened gills, that are wet with seawater, usually by taking water from moist sand or by running into the surf and letting the waves wash over them. Therefore, the inter-tidal zone is suitable for their survival. Ghost crabs also have the ability to change their colour to match their surroundings by adjusting the concentration and dispersal of pigments within their chromatophores. This enables them to escape from their predators.

Monday, April 7, 2014 · 7:47 PM · 0 comment(s).

Ulva lactuca

Ulva lactuca, more commonly known as sea lettuce, is a thin flat green alga growing from a discoid holdfast. Individual blades can grow to be more than 400mm in size. It can attach to rock via a small hold-fast, so as to survive regular tides. They have smooth waxy leaves which helps to retain water. Therefore, it is also important for organisms living in coastal areas where the salt from the sea water causes many organisms to be dehydrated.

· 7:18 PM · 0 comment(s).

Polycladida

Polycladida which is also known as marine flatworms do not have circulatory and respiratory organs. Hence, in order for them to survive, the exchange of gas takes place in the form of simple diffusion; Oxygen and nutrients pass through their bodies and Carbon dioxide is able to leave all parts of the body. Therefore, many of the flatworms have flat ribbon-like or leaf-like shapes like the one in the picture above so as to have larger surface area to volume ratio, allowing diffusion to occur at a faster rate.

· 7:36 AM · 0 comment(s).

Mangroves

Mangroves are various types of trees and shrubs that are found in saline coastal areas in the tropics and subtropics. However, unlike normal trees, these mangroves in the above picture have roots above the ground which is also know as pneumataphores as shown in the picture above. This structure allows oxygen to be transferred to the roots trapped below ground in the low-oxygen soils.
Also, these roots are also highly impermeable and are highly suberised which act as an ultrafiltration mechanism to exclude sodium salts when taking in water.

· 7:13 AM · 0 comment(s).

Archaster Typicus

Archaster typicus, more commonly known as common sea star, has a central disc and five arms. Their arms are flexible so that they would be able to turn themselves over when they are flipped. Their mating style is unique to them. The male (comparably smaller in size) climbs onto the female so as to release his sperm when the female releases her eggs to increase the chances of external fertilisation to take place. The bountiful population of common sea stars on mainland Singapore have been largely wiped out due to floods in Johor in 2007 that caused their disintegration.

· 7:07 AM · 0 comment(s).

Casuarina Equisetifolia

Casuarina equisetifolia, which is more commonly known as Casuarina trees or Rhu is from Kingdom Plantae. Due to the limited space in Pulau Hantu, Casuarina move nearer to coastal areas. Thus, it is important for them to have water-retaining adaptations as living in Coastal Areas increase the chances of getting dehydrated. Firstly, Casuarina has a dense mat of roots which harbours symbiotic nitrogen fixing bacteria in its nodules, thus allowing it to take in large quantities of groundwater. This also allows it to survive in infertile areas. Their leaves are also reduced in size to retain water.

· 4:34 AM · 0 comment(s).

Introduction to Theme: Adaptations For Survival

The theme our blog focuses on

ADAPTATIONS FOR SURVIVAL

In our posts, we will be exploring how the organisms at Pulau Hantu have different adaptations which aids them in survival. These survival adaptations give organisms the ability to withstand the conditions of their environments. Whether it is to cope with the weather of their habitat or to avoid predation to stay alive, plants, animals and other organisms have a multitude of survival strategies.

Friday, March 28, 2014 · 6:15 AM · 0 comment(s).