Lecture 22: Panama

Question 1

What is the isthmus of panama?

Answer 1

Dry land connecting north and south america –> first time americas were linked since pangaea

Question 2

How did the isthmus of panama affect ocean circulation?

Answer 2

Warm water used to travel across but is now diverted up towards the northeast (gulf stream)

Question 3

How do we know panama used to be underwater?

Answer 3

Fossil remains of many species of shallow water foraminiferans in Miocene sediments in Caribbean

Question 4

What were the direct effects of the isthmus of panama?

Answer 4

land bridge acted as both a barrier and a corridor for disperal –> barrier for aquatic life and corridor for terrestrial life

Question 5

What were the indirect effects of the isthmus of panama?

Answer 5

Climatic changes, geological changes lead to subsequent changes in distribution, ecology

Question 6

What are “heralds and legions”?

Answer 6

Heralds are smaller groups of early colonizers
Legions are the main larger invasion group that came after

Question 7

What was the aftermath of the exchange between north and south american following the formation of the isthmus of panama?

Answer 7

most SA mammals are descendant of NA mammals
many SA mammals went extinct
Birds, reptiles and amphibians less affected