Exhibition:

The origin of life:

The origin of life is an exhibition comprising six tanks containing a selection of six different species. The focus of this exhibit to explore the numerous mechanisms that animals develop for catching their prey and avoiding becoming someone else's dinner.The exhibition is arranged into different sections:

1. The dance of the jellyfish:

The graceful dancers in this circular tank are the beautiful Aurelia aurita , commonly know as the moon jellyfish. Like most types of jellyfish, these cosmopolitan creatures are largely at the mercy of tides and currents, living in seas and oceans the world over.

Jellyfish are invertebrates of the phylum Cnidaria, and consist mostly of water (around 90%). They are covered with an outer protective layer and their tentacles are sensitive enough to detect nearby prey. Rather than actually hunting, jellyfish spread their tentacles over the largest area possible. Their tentacles are covered with stinging cells which paralyze their prey.

The beauty of the jellyfish owes itself largely to their primitive form and slow evolution. Their apparent simplicity, however, conceals the surprising and complex strategy of their life cycle. Primitive as they may seem, they are able to synthesize the two different types of marine life forms: benthonic (rock or sea bottom dwellers) and pelagic (open sea). In the two smaller side tanks we can see the earlier stages of the jellyfish before it becomes an adult. In the first phase the polyps attach themselves to fixed structures. They then grow into adult medusas and break away from their anchor, drifting freely in the water. The polyps divide and bud into more young jellyfish. They feed mainly on a variety of tiny crustaceans called artemia, which they absorb into their interior layer.

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2. marine filters:

The species in this tank have developed surprising ways to keep up in the struggle for survival. Such challenges often bring about some strange and rather curious feeding strategies.

Species such as mussels, peacock fan worms and sea acorns enter into the category of filterers. Their feeding strategy is to strain small organic materials suspended in the water and extract their nutritive substances.

Each filtering species has evolved specialized mechanisms for exploiting its food resources. The bivalve, hermaphrodite mussel uses its cilia (fine hairlike threads) to filter phytoplankton and other particles its ingests as its food source. Spirographs, or fan worm, aim their "feathers" toward the current so that the movement of the water can push the food particles through their fan-like filtering mechanism. This species reproduces asexually and can quickly shut itself up when it feels threatened by another animal.

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3. Grazing the ocean:

This tank contains a series of animals that represent species whose feeding strategy is based on marine plants.

Sea urchins, limpets and sea snails are just some of the animals whose diet consists of algae and other types of marine flora. Two of the best examples here are:

Sea urchins are ferocious grazers able to feed on calcareous algae, which can often be as hard as live coral. Sea urchins are of the phylum Echinodermata. Their bodies are oval with five-part symmetry and are covered with pointy spines. They form suckers on the ends of their feet.

Sea hares are mollusks classified as gastropods. Also known as sea slugs, these creatures have only one valve and feed on algae.

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4. We like it all:

The grey mullet, the spiny lobster, the fiddler crab and crustaceans as a whole are species that feed on both decomposed and live matter. In contrast to many other species, their unspecialized diet based on a variety of nutritional sources makes them natural survivors.

Let's take a closer look at three examples seen in this tank. Red starfish seen here are echinoderms (exhibit radial symmetry), which generally have five arms (although others can have 7, 12 or more). The head and mouth of the starfish are located in the central part of its body. Although the starfish in this tank are red, they also come in many other colours. This species also has sensors in its feet to distinguish light. The red starfish feeds mostly on mussels, wrapping its arms around the two shells and slowly forcing them apart. It then turns its stomach inside out and inserts it through the narrow gap between the shells of the mussel.

Starfish reproduce sexually (their eggs are fertilized in the water), but they can also reproduce asexually. If it loses an arm, not only will another one grow back, but a new starfish can grow from the chopped off arm. Starfish move by means of tube feet or with sudden movements.

Beadlet anemones belong to the phylum Cnidaria (same as the jellyfish). They are uniform in colour and have 200 tentacles which they can readily retract if the animal is disturbed. Beadlet anemones feed mainly on small fish, crustaceans and mollusks. It adheres itself to rocky surfaces and has stinging properties in its tentacles.

Lastly, the spiny lobster is a crustacean classified among invertebrates as an arthropod with antennae and mandibles. They have chewing appendages and eyes in their antennae. Their hardness of the exoskeleton is due to calcareous salt deposits.

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5. The frontier:

This tank represents the transition zone between the rocky areas and the sand. Here visitors can take a look at the different marine animals that inhabit this area and examine the variety of ways they have learned to adapt to their habitat. Despite the fact that human behaviour has seriously affected intertidal areas, particularly with regard to pollution and dumping, many of the species seen here can still be found on and in the vicinity of sandy beaches.

If you look carefully, in this tank you'll see how well the turbot, masters of camouflage, are able to change colour to blend in with the sea bed - yet another example of how nature finds ways of adopting different strategies for survival.

In this tank we can observe species that live in the sandy and rocky areas along our coastline and in coastal waters, including sage, pouting, the common pandora (a pelagic fish in the sea bream family) or the common sea bream (pelagic fish). This tank could be described as representative of the so-called Zumaia shallows.

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6. Carnivores:

There is a wide range of carnivorous species that feed on other marine animals. In this tank we are going to focus on the animals that have developed peculiar ways of hunting their prey. Besides developing one of the most sophisticated camouflaging mechanisms, the octopus is also a very clever predator. Another voracious example is the monkfish or angler fish. This fish bases its strategy on tricking its prey, dangling the antenna located on the top of its head in front of it's mouth to lure unsuspecting prey. This fishing pole and bait strategy makes other fish think it's smaller than it actually is. When the smaller fish comes close the bait, the giant mouth of the monkfish snatches up its prey and literally absorbs it. The mouth of creature is the same size as the rest of its body, lending to its bizarre appearance.

In contrast with the more aggressive and depredatory style of the monkfish or octopus, anemones have a more "passive" way of feeding. Although no less efficient - and perhaps even more so - they wait patiently for their prey (small fish and crustaceans) to draw near and get trapped in their paralyzing tentacles. The anemone, just like the jellyfish, is in the phylum Cnidaria. It has between 180 and 200 stinging tentacles and attaches itself to rocky surfaces.

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