Is there a difference in vertebrate class representation of tetrapod arrivals from Africa vs. Asia
(the Indian subcontinent and Southeast Asia)?
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H0: There is no difference in tetrapod class representation between those arriving from Africavs. Asia during the Cenozoic. Reject. Conclusion: Mammals and reptiles are far more likely thanbirds to have arrived from Africa than from Asia. |
19.293, df = 3, P<0.001 |
<0.001 |
Is this source difference dependent on the direction of ocean currents?
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H01: There is no difference in tetrapod class representation of African vs. Asian arrivals beforethe mid-Miocene. Reject. Conclusion: Before the shift in ocean currents, mammals andreptiles are more likely than birds to have arrived from Africa. |
8.603, df = 3, P = 0.035 |
= 0.017 |
H02: There is no difference in tetrapod class representation of African vs. Asian arrivals afterthe mid-Miocene. Reject. Conclusion: After the shift in ocean currents, mammals andreptiles are more likely than birds to have arrived from Africa. |
13.03, df = 3, P = 0.005 |
= 0.005 |
H03: There is no change in overall tetrapod class representation among arrivals before andafter the mid-Miocene. Fail to reject. Conclusion: Both before and after the mid-Miocene,birds and mammals dominate arrivals. |
2.653, df = 3, P = 0.448 |
= 0.482 |
H04: There is no change in geographic source among arrivals before and after the mid-Miocene.Fail to reject. Conclusion: Both before and after the mid-Miocene, most colonizersarrive from Africa. |
3.097, df = 3, P = 0.377 |
= 0.348 |
What, then, was the effect of the shift in ocean currents?
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H01: There is no change in dispersal advantage of vertebrate arrivals from before to afterthe mid-Miocene. Reject. Conclusion: After the mid-Miocene, the percentage ofdispersal-disadvantaged taxa colonizing Madagascar decreases. |
17.392, df = 1, P<0.001 |
<0.001 |
H02: There is no change in locomotor type of vertebrate arrivals from before to after themid-Miocene. Reject. Conclusion: After the mid-Miocene, the percentage of volantcolonizers increases markedly. |
15.335, df = 2, P<0.001 |
<0.001 |