Species are adapted in different ways to be successful in different habitats Case study: the marine environment. This habitat presents a number of challenges for the species that live there. How are organisms adapted to survive in the marine environment?
The water itself is the biggest challenge for most species that live in the marine environment. It is dense and viscous compared to air and therefore more difficult to move through. Species that need to move through the water quickly need to have a fusiform (streamlined) body shape, strong muscles and fins to cut through the water. For example the yellowfin tuna shown above (Thunnus albacares).
Underwater communication is also a challenge. Some species use visual communication, e.g. giant cuttlefish (Sepia apama) but this only works at short distances in good visibility. Larger species that need to communicate over long distances therefore use sound, as this travels better underwater. For example humpback whales (Megaptera novaeangliae) sing to communicate during migration and also in courtship.
The regulation of body temperature in the water can be a problem for species that require warmth for survival. This is because the water is generally cold and species will lose heat to a cold water environment. Marine mammals like the walrus (Odobenus rosmarus) tend to use fur and/or blubber, as insulation. Blubber insulates better than fur when diving deep and blood flow can be regulated through it to get rid of excess heat if required (hence the pink colour of the walrus at the surface). Some species also use behavioural adaptations to regulate their temperature, e.g. the Galapagos marine iguana (Amblyrhynchus cristatus) is cold blooded, therefore relies on basking in the sun to generate enough heat to enable it to swim in the cold ocean and feed on algae. The Galapagos marine iguana basks on hot rocks in between feeding bouts.
Some marine species are diurnal and others are nocturnal. Diurnal means active at daytime and nocturnal means active at night. The humphead parrotfish (Bolbometopon muricatum) is diurnal and secretes a mucous cocoon at night to escape detection by predators. The common lobster (Homarus gammarus) is nocturnal and shelters in a rock crevice ‘den’ during the day.
Camouflage is also used by species living in the marine environment. It helps species avoid detection by other species. Camouflage can be used to avoid predation or can be used by predators to sneak up on prey. This pygmy seahorse (Hippocampus bargibanti) is a great example of this, camouflaged amongst a fan coral – can you spot it? Click mouse to reveal the seahorse.
All of these adaptations have been leading up to two themes: either escaping predation or being an effective hunter. There are many other possible adaptations that make species good at escaping predation: Safety in numbers – living in a group like these five-lined snapper (Lutjanus quinquelineatus) makes it a lot less likely that you will be eaten. 2. Burrowing into the sand or being camouflaged to avoid detection, like the gulf torpedo ray (Torpedo sinuspersici). 3. Physical protection such as armour or spines also deters predators, like this purple sea urchin (Strongylocentrotus purpuratus).
There are also various adaptations to make you a good predator: You could be venomous like this yellow-bellied sea snake (Pelamis platurus) to paralyse or kill your prey You could work as a team and hunt in a group like these emperor penguins (Aptenodytes forsteri) Alternatively, like the great white shark (Carcharodon carcharias), you could have speed, strong jaws and massive teeth!
Demonstrate how to use the ARKive search – for keyword searches, type in keyword into search bar, select “all” tab and click search to search the whole website for this word. Keywords can be combined for more powerful searches using the “+” symbol e.g. “rainforest+predator”
This is an example of a prey species adapted to the marine environment, designed by the ARKive team. The adaptations from different marine species are included in the annotations.
- These are some suggested themes for adaptations that it might be useful for the students to think about when designing their own species.
What is adaptation?
A structure or behavior that helps an organisms to survive.
• Adaptations allow species to live successfully in their habitat.
• Species living in different habitats need different adaptations.
Emperor penguin Great white shark
Yellow-bellied sea snake
Design your own species!
• Divide into small groups
• Each group will be given a habitat card and either predator or prey
• Using the ARKive website (www.arkive.org), find examples of
predator/prey species adapted to your habitat.
• Using this research, design your own species!
Meet the spiny skipper – a prey species adapted for the marine environment.
Things to think about…
• What does it eat?
• Is it brightly coloured or camouflaged?
• How does it move?
• Does it live with other members of the same species?
• How does it keep warm / cool?
• Where does it live? E.g. trees? Burrows? Underground?
• How big is it?