Download Molecular Evolution

Chapter 03
Author: Lee Hannah
FIGURE 3.1 Bleached Coral.
El Ni ñ o events in 1982 – 1983 and 1997 – 1998 bleached corals in reefs
throughout the world. Bleaching is an increasingly common phenomenon
even in non-El Ni ñ o years. This coral head in St. Croix bleached in 1995.
Courtesy U.S. National Oceanic and Atmospheric Administration.
FIGURE 3.2 1997 – 1998: A Deadly Year for Corals.
The right panel shows corals bleached in the El Ni ñ o event of 1997 – 1998. The left panels show a
single coral head pre- and postbleaching: (a) prebleaching, (b) bleached coral head, (c) partially
recovered coral head, and (d) fully recovered postbleaching. Left Source: Manzello et al., 2007; Right
Source: Courtesy U.S. National Oceanic and Atmospheric Administration.
FIGURE 3.3 Rising Temperature Maxima Exceed Bleaching Threshold.
As global mean temperature rises, the frequency of events that exceed the bleaching threshold
increases. The threshold varies in different regions. This chart illustrates the effect of
increasing base temperatures on the extremes that drive bleaching. Modifi ed from Marine
Fresh Water Research , Volume 50, 1999. CSIRO Publishing.
FIGURE 3.4 Edith ’ s Checkerspot Butterfl y Range Shift.
Southern populations of Edith ’ s checkerspot butterfly are becoming extinct (shaded
squares) more frequently than northern and montane populations, resulting in a
northward and upslope range shift. Reprinted by permission from Macmillan Publishers
Ltd.
FIGURE 3.5 Edith ’ s Checkerspot Butterfl y (Euphydryas editha).
From http://www.nps.gov/pinn/naturescience/butterfl y.htm.a
FIGURE 3.6 Penguins and Climate Change.
Emperor penguin (Aptenodytes forsteri) populations are declining in
Antarctica with climate change. Photo Courtesy of NOAA.
Photographer: Giuseppe Zibordi.
FIGURE 3.7 Declining Krill in Southern Oceans.
Krill abundance is decreasing in areas bordering Antarctica, whereas salp densities are
increasing. Krill depend on ice algae for summer population growth. Declining sea ice
due to climate change reduces algal density and depresses krill populations. Salps
increase in their place. The maps show change in krill (top) and salp (bottom)
abundance. These changes have had profound impacts on food webs in the
southern oceans. Reproduced with permission from Nature .
FIGURE 3.8 Correlation Between Sea Ice and Krill Density From
Region Shown in Figure 3.7.
Reproduced with permission from Nature .
FIGURE 3.9
The silver spotted skipper (Hesperia comma) has expanded its range
threefold in Britain since 1982.
Reproduced with permission from Nature .
FIGURE 3.10 Large-winged Forms Increase in Expanding Range Margins.
Insects have longer wings in expanding range margins. The conehead bush cricket, Conocephalus
discolor (left map) and Roesel ’ s bush cricket, Metrioptera Roeselii (right map), have undergone
recent range expansions due to climate change. Blue circles indicate historical range, with yellow
and red circles denoting progressive expansion in these species. Long-winged forms are more
common in populations on the range margin (graphs). Locations with fewer years since fi rst
observation are recently colonized areas on the range margin. Reproduced with permission from
Nature .
FIGURE 3.11 Climate-Linked Invasion.
Invasion of exotic plant species is correlated with reduced drought days in
Switzerland. Removal of climatic stress may remove important constraints on
the spread of these species. Reproduced with permission from Nature .
FIGURE 3.12 The Quiver Tree, Aloe Dichotoma .
Aloe dichotoma is a bellwether of climate change. Populations are declining in the
north and at lower elevations, with the only northern stronghold remaining at high
elevation. From Wikimedia Commons.
FIGURE 3.13 Drying Trends in Monteverde Cloud Forest, Costa Rica.
Number of dry days per year in Monteverde and departure of nearby sea surface temperature
from long-term average. Note the long-term increase in the number of dry days and the peak in
1987, which is the year of the disappearance of the golden toad. Reproduced with permission
from Nature .
FIGURE 3.14 Changes in Diversity in Arctic Lakes.
Diatom diversity has increased in arctic lakes due to warming during the past 50 years.
An increase in diversity in sampled lakes is indicated for the arctic and in more detail for
four regions with especially rich records in the insets. From Smol, J. P., et al. © 2005,
National Academy of Sciences U.S.A.
FIGURE 3.15 Expanding Malaria Zone.
Malaria is currently rare in the highlands of Zimbabwe (left panel). Malaria parasites mature
up to 10 days more rapidly under projected temperature increases. This allows the disease
to persist in formerly inhospitable areas. The right panel shows the projected spread of
malaria into the Zimbabwe highlands by 2050 due to this effect. Orange and red colors
denote suitable conditions for malaria transmission, and bluegreen colors areas with poor
conditions for transmission. From Patz, J. A. and Olson, S. H. © 2006, National Academy of
Sciences U.S.A.
Un- Figure 3.1 Arctic fox (a) and red fox (b). From (a) Wikimedia
Commons and (b) U.S. Fish and Wildlife Service.
Un- Figure 3.2 Polar bears (Ursus
maritimus). From Wikimedia Commons .
Un- Figure 3.3 Pika ( Ochotona princeps ). From
National Park Service, U.S.A.
Un- Figure 3.4 Keel-billed toucan ( Ramphastos sulfuratus ).
From Wikimedia Commons.
Un- Figure 3.5 Projected changes in 17 ° (yellow) and 13 ° C (white) isotherms that limit
the distribution of avian malaria under current and 2 ° C warming conditions. Changes are
shown for Hanawi Reserve (blue boundary) on the island of Maui (a), Hakalau Refuge
(blue boundary) on Hawaii (b), and the Alakai swamp region on the island of Kauai (c).
From Benning, T. L., et al. © 2002, National Academy of Sciences U.S.A. .