Marine Iguana

Question 1

Galapagos

Answer 1

Volcanic archipelago chain straddling zone where warm and cold ocean currents meet.
Corals, penguins, fur seals, hammerheads.
Geology, ecology and evolution intersect dramatically, underpinning pivotal roles the area has played in understanding evolution

Question 1

Phylogeny

Answer 1

Recent members of the iguana clade.
Amblyrhynchus is a monospecific lineage forming a clade that is endemic to the Galapagos. Clade includes Amb with 3 species of galapagos land iguana.

Question 2

Speciation and hybridization

Answer 2

Iguana are strong swimmers and can move between islands, but they are far and currents are strong preventing mixing.
Macleod 2015 use marine iguana to highlight interaction between effects of speciation and hybridisation on genetic diversity.
Show evidence for within-island speciation and between-island hybridisation
High levels of island specific genetic diversity appear v recently (50,000 years ago), may be linked to volcanic events.

Question 3

Adaptations

Answer 3

Intertidal feeding: Anolis agassizi partly feeds on crustacea, Diploglossus hancocki entirely on crustacea.
Marine iguana diverged from land based cousins 4 mil years ago show many adaptations:
- long claws to cling onto rocks.
Laterally compressed tail for swimming
Salt gland in nostril
Algae, red and green
tricuspid teeth
Dark skin for UV protection and warming

Question 4

Thermoregulation

Answer 4

Face challenges of cold water and hot arid land with cool nights
Grouping behaviour
burial in sand

Question 5

Foraging

Answer 5

Feeding strategy is weight related.
Sub tidal feeders typically around 2kg and above
Intertidal/subtidal are 1-2kg
Intertidal below 1.5kg

Question 6

Salt tolerance

Answer 6

Nasal salt gland excretes excess salt
Highly efficient at filtering out Na and Cl ions from blood
Expelled in concentrated brine which is ejected by sneezing or snorting

Question 7

Climate effects

Answer 7

Change in ocean current patterns can have ecological effects.
Increased el nino:
- loss of green and red algae.
- brown is indigestible, leads to starvation, skeleton shrinkage, death and breeding failure.
Invasive species increase competition.

Question 8

Marin reserve

Answer 8

Lacking and poor management of human uses
Illegal fishing
Littering at visitor sites
Local pollution at ports
Shipwrecks and oil spills