Ecosystems in our surroundings

Classify these ecosystems as terrestrial or aquatic: a lagoon, a beech wood, a salt marsh, a grassland, a reef, and a scrubland.

State whether these ecosystems are freshwater or marine: the River Tagus, the Cantabrian Sea, a mountain lagoon, a pond, and the Atlantic Ocean.

Point out two differences between a freshwater ecosystem and a marine ecosystem and explain why most fish cannot move from one environment to the other.

Name two terrestrial ecosystems characteristic of the Iberian Peninsula and one specific to the Canary or Balearic Islands, mentioning a typical species from each.

Name two characteristic species of the Mediterranean forest and two of the Atlantic forest of the Iberian Peninsula.

In the Canary Islands, there are species, such as the El Hierro giant lizard, that live nowhere else in the world (endemic species). Explain the role island isolation plays in the occurrence of endemic species.

Look at the ecosystem classification diagram. State in which box (1, 2, or 3) you would place each of these ecosystems: a holm oak wood, a coral reef, a mountain lagoon, a dehesa (wooded pastureland), a posidonia meadow, and a river.

A marine aquarium and a freshwater aquarium need very different care. Relate these differences to the conditions of the natural environment of each type of fish.

During the expansion of a marina over a Posidonia oceanica meadow, the construction work drastically increases water turbidity and deposits fine sediments onto the seabed. The project developer claims: 'The meadow will not suffer any damage because the breakwater is being built 50 metres away and we are not directly uprooting any plants.' Refute this claim by explaining the physiological effects that turbidity and sedimentation cause on these marine plants. Furthermore, predict two cascading ecological consequences on the coastal ecosystem and local fisheries.

Explain in your own words the difference between a natural ecosystem and one transformed by humans, and give an example of each.

A dehesa is a holm oak or cork oak wood cleared by humans to be used as pasture and farmland. Explain why it is considered a human-modified ecosystem while also being an example of sustainable land use with high biodiversity.

The plant biodiversity of three 500 m² plots in a Mediterranean ecosystem is analysed: a mature holm oak forest (24 species), a reforested pine forest (9 species), and a commercial eucalyptus plantation (5 species). After a period of extreme drought and a defoliating insect outbreak, the eucalyptus plantation lost 65% of its leaf mass, whereas the holm oak forest was barely affected (less than 8% damage). Interpret these results by relating species diversity, vertical vegetation stratification (herbs, shrubs, trees), and ecological niches to the resilience and self-regulation capacity of each ecosystem.