The Galápagos marine iguana (Amblyrhynchus cristatus), a unique reptile endemic to the Galápagos Islands, has evolved highly specialized traits to forage in cold marine environments. Occasionally, heavy ocean storms sweep a very small number of these iguanas to remote, uninhabited islets, establishing new, isolated colonies.
State the biological term for the loss of genetic variation that occurs when a new, isolated population is established by a very small number of individuals from a larger parent population.
Adaptations of organisms to their environment can be categorised into three main types:
The table below lists four distinct evolutionary adaptations of the marine iguana.
Complete the table by identifying which of the three types of adaptation is represented by each trait.
| Marine iguana trait | Type of adaptation |
|---|---|
| Slowing its heart rate (bradycardia) and reducing blood flow to non-essential organs during deep cold-water dives to conserve oxygen | |
| Flattened, laterally compressed tail that acts like a paddle to propel the iguana through strong ocean currents | |
| Basking on hot volcanic rocks in large groups to absorb thermal energy and raise body temperature after diving | |
| Excreting highly concentrated salt crystals from specialized nasal glands to eliminate excess salt ingested from seawater |
