Adaptive radiations and mass extinctions
Adaptive radiations
• Two main pathways:
•
•
Exploitation of environments not occupied by
competitors
Key innovations can transform how organisms interact
with their environment
• Paves the way for adaptive radiation
Adaptive Radiations
• eg Pelagic fishes
Summary of the fossil record of Pelagia, indicating rapid appearance of constituent
lineages in the Paleogene.
Miya M, Friedman M, Satoh TP, Takeshima H, Sado T, et al. (2013) Evolutionary Origin of the Scombridae (Tunas and Mackerels): Members of a
Paleogene Adaptive Radiation with 14 Other Pelagic Fish Families. PLoS ONE 8(9): e73535. doi:10.1371/journal.pone.0073535
http://127.0.0.1:8081/plosone/article?id=info:doi/10.1371/journal.pone.0073535
Mean depth ecology of Pelagia reconstructed on the timetree
Pelagia
Evidence for
monophyly
Mass extinctions
• Background extinction:
•
•
If clade’s origination rate α drops, it may disappear
A single extinction event may have minimal impacts on
an ecosystem
• Mass extinction
•
•
An increase in extinction rates, a decrease in origination
rates (or both) that results in a deviation from
background rates
Has cascading effects
Era
Period
Range of Global Biodiversity
The Sixth Extinction
QUATERNARY
TERTIARY
76% species
CRETACEOUS
JURASSIC
TRIASSIC
80% species
Activity in Central Atlantic magmatic
province, increase CO2, increase acid,
calcification crises, drop in origination
96% species
Siberian traps, sudden release of
methane, warming, marine anoxia and
acidification, rise in extinction rates
75% species
Ocean anoxia (?), cooling followed by
warming, possible plant diversification,
fall in CO2, drop in origination
PERMIAN
CARBONIFEROUS
DEVONIAN
Asteroid, rapid cooling, preceded by
vulcanism in India, erosion, ocean
eutrophication and anoxia, rise in
extinction rates
SILURIAN
ORDOVICIAN
CAMBRIAN
86% species
Cooling, movement of Gondwana into
polar region (?), glaciation, marine
regression and transgressions, uplift of
Appalachians, rise in extinction rates
Integrating concepts - Evolution of coral reef fish diversity
•
Stems of lineages
extend in the
Cretaceous
Near et al. 2013
Evolution of coral reef fish diversity
•
•
•
“Crown origins” are
associated with the
aftermath of the K-Pg
mass extinction event (65
MY ago)
Reef associated forms
more resistant to
extinction than non-reef
relatives
Most extant forms
studied are of Miocene
age (23-5mya)
Coral reef fish biogeographic provinces
•
Biogeographic delineation of tropical
Realms, Regions, and Provinces based on
species dissimilarity analysis of
Kulbickiet al. (2013). (reviewed by
Cowman 2014)
Key events that have affected coral reef fish distribution
• Hard barriers – vicariance events
•
•
Terminal Tethyan Event (TTE) – 12-18 MY ago
Isthmus of Panama (IOP) 3.1 MY ago
• Soft barriers (porous)
•
•
East Pacific Barrier (EPB) – open ocean, in effect for 65
MY (some dispesal, most from west to east)
The Indo-Australian Archipelago
•
•
•
The Indian Ocean
The Indo-Australian Archipelago (IAA) hotspot
Central West Pacific Islands
Tethys Ocean
• https://vimeo.com/14507389
• Closure approx 12-18 MY ago
Comparative analysis of reef fishes
Cowman and Bellwood 2013
• Labridae (wrasse)
•
Spawn in water column
• Pomacentridae (dameselfishes)
•
Demersal eggs, shorter larval stages
• Chaetodontidae (butterfly fishes)
•
Spawn in water column
EP- Eastern Pacific
Atl - Atlantic
In - Indian Ocean
AAA – IAA hotspot
CP - Central Pacific Islands
GL - Global
Distribution of reconstructed vicariance events associated with barriers between
biogeographic regions. (a) Schematic diagram of world map identifying boundaries
between regions (dashed lines) with known historical barriers: IOP and TTE (see text).
Lines for IOP and TTE are extended down indicating the timing of known final barrier
formation; (b) mean age (+s.e.) of vicariance events associated barriers (L, Labridae; P,
Pomacentridae; C, Chaetodontidae) and (c) distribution of vicariance events across
each barrier. Each circle represents a vicariance event across the associated barrier.
Family is indicated by circle colour as in (b) (Labridae, grey; Pomacentridae, white;
Chaetodontidae, black).
Biogeographic ages of species within families
EP- Eastern Pacific
Atl - Atlantic
In - Indian Ocean
AAA – IAA hotspot
CP - Central Pacific
Islands
GL - Global
Biogeographic ages of species of the families Labridae, Pomacentridae, and
Chaetodontidae. Plot shows mean (circle) and 95% CI (whiskers) of the distribution of
ages of origination of extant lineages in each biogeographic region, and globally for the
Labridae, Pomacentridae, Chaetodontidae
Most coral reef species are of Miocene age ( 23– 5 mya)
Shifting hotspots
Fig. 1. Generic α-diversity of large
benthic foraminifera in (A) the
late Middle Eocene (42 to 39 Ma), (B)
the Early Miocene (23 to 16 Ma),
and (C) the Recent. Solid lines delimit
the West Tethys, Arabian, and
IAA biodiversity hotspots (tables S1 to
S3). Note the relocation of
hotspots across the globe. Where
multiple studies occurred at a single
locality, the highest recorded diversity is
reported. (Renema et al 2008)
Taxa in the IAA share
historical diversification
events
Role of refugia
Location of coral reefs, past
isolation, and current fish
richness. Maps of (A) the coral
reef area per 5°-by-5° cell
averaged for the periods of
marked coral reef contraction,
as characterized by lower
sea surface temperature and
sea level (square degree); (B)
standardized isolation from
stable coral reef areas across
the Quaternary (kilometers);
and (C) current global richness
of reef fishes (number of
species)
Quaternary = 2.5 MY ago
to present
Pellesier et al. 2014