The Biosphere
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False-color composite image of global photoautotroph abundance from Wikimedia Commons
Terrestrial Biomes
Large-scale biological communities sharing similar plant growth forms
- convergent adaptations to similar physical environments
Cain, Bowman & Hacker (2014), Fig. 3A
Terrestrial Biomes
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Cain, Bowman & Hacker (2014), Fig. 3.5
Terrestrial Zoogeographic Regions
Published as “an update of Wallace’s zoogeographic regions”
Map from Holt et al. (2013) Science
Biomes & Biogeographic Realms
World Wildlife Fund team identified 14 terrestrial biomes
Map from Olson et al. (2001) Bioscience
Ecoregions
… and 867 distinct ecoregions
Map from Olson et al. (2001) Bioscience
Tropical Rainforests
Dominant plants = broad-leaved
evergreen trees
Also epiphytes, lianas, palms, and
generally sparse understory
More-or-less continuous
growing season
Contain ~50% of Earth’s species
in ~11% of terrestrial veg. cover
Cain, Bowman & Hacker (2014), Fig. 3A
Tropical Rainforests
E.g., scatter-hoarding of seeds by rodents
Photo of agouti and Astrocaryum palm fruits by Christian Ziegler; Figure from Jansen et al. (2012) PNAS
Tropical Seasonal Forests & Savannas
Tropical dry forests
Thorn woodlands
Tropical savannas
Resource availability, fire & large
herbivores help determine the
balance between grasses vs.
woody species
Pronounced wet / dry seasons
Cain, Bowman & Hacker (2014), Fig. 3B
Tropical Seasonal Forests & Savannas
E.g., protection of plants against herbivores by ants
Photo of Pseudomyrmex on Vachellia (formerly Acacia) – Wikimedia Commons; Table – Janzen (1966) Evolution
Hot Deserts
Sparse populations of plants &
animals
Succulent plants are common
Sustained periods of high temp. &
low water avail.
Cain, Bowman & Hacker (2014), Fig. 3C
Hot Deserts
E.g., large-male advantage in lek-mating tarantula hawks
Photo of Tarantula Hawk and Tarantula – http://blogs.sandiegozoo.org/tag/tarantula-hawk;
Figure from Alcock (1981) Behavioral Ecology & Sociobiology
Temperate Grasslands
Dominant plants = grasses
Warm, moist summers &
cold, dry winters
Some have sufficient rainfall to
support woody veg., but fire &
grazers maintain grasslands
Soils rich in organic matter
Cain, Bowman & Hacker (2014), Fig. 3D
Temperate Grasslands
Large ungulate & marsupial (in Australia) grazers are common
Photos of pronghorn antelope and red kangaroo from Wikimedia Commons
Temperate Shrublands & Woodlands
Winter rainy season (e.g.,
Mediterranean-type climates)
Fire is a common feature
Sclerophyllous leaves are
common
Cain, Bowman & Hacker (2014), Fig. 3E
Temperate Shrublands & Woodlands
Resprouting is common
Photo from http://www.eco.science.ru.nl/plantecology/Estrela/pig_fireecology.html
Temperate Deciduous Forests
Deciduous leaves owing to
freezing temperatures
Sufficient rainfall & soil fertility to
support tree growth
Cain, Bowman & Hacker (2014), Fig. 3F
Temperate Deciduous Forests
Insect populations sometimes outbreak
Photo of tent caterpillars from http://www.twincities.com/outdoors/ci_25948887/minnesota-tent-caterpillaroutbreak-concerns-eased-by-dnr
Temperate Evergreen Forests
From warm coastal zones to cool
maritime climates
Generally on nutrient-poor soils
Northern Hemisphere – needleleaved conifers
Southern Hemisphere - needleleaved & broad-leaved
Cain, Bowman & Hacker (2014), Fig. 3G
Temperate Evergreen Forests
Photo of British Columbian rainforest from Wikimedia Commons; K. Harms photo of Florida pine savanna
Boreal Forests / Taiga
Coniferous species
Extreme weather
Permafrost common
Cain, Bowman & Hacker (2014), Fig. 3H
Boreal Forests
Immense carbon pools
Photo of Canadian taiga from Wikimedia Commons
Tundra
Beyond treeline
Dominated by sedges, grasses,
forbs & prostrate shrubs
Primarily in the Arctic
Extreme weather
Permafrost common
Cain, Bowman & Hacker (2014), Fig. 3I
Tundra
Prey can be seasonally very abundant during short growing season
Photo from http://www.reddit.com/r/itookapicture/comments/1nh6eo/itap_of_a_few_mosquitoes_in_alaska/
Ecotones
Transition zones between biomes or ecosystems
Photo of lakeside ecotone from Wikimedia Commons
Where the Land Meets the Sea
Estuary – junction of a river & ocean
Mangrove – shallow
estuaries & mudflats with
salt-tolerant evergreen
woody species
Salt Marsh – found on
sediments carried to
shorelines by rivers
Photos of Amazon estuary, a mangrove & a salt marsh from Wikimedia Commons
Where the Land Meets the Sea
Beaches / Sandy Shores –
unstable substrate limits
opportunities for plants, so limited
opportunities for animals
Rocky Intertidal – stable
substrate alternates
between terrestrial &
marine
Etc.
Photos of a Galapagos sandy / boulder beach & a rocky intertidal shoreline from Wikimedia Commons
Marine Biomes
Coral Reef – warm,
shallow water
Kelp bed – large brown
algae in clear, shallow,
temperate oceans
Photos of coral reef, kelp bed & seagrass bed from Wikimedia Commons
Seagrass bed – flowering
plants on subtidal mud or
fine sand
Marine Biomes
Deep sea – extreme pressure & temperature; no light, so
limited, patchy energy supply
Etc.
Photo of 1700 m deep gray whale fall from Wikimedia Commons;
photo of octopus that broods eggs for 4 yr at ~1700 m deep from
http://www.newsweek.com/octopus-broods-eggs-record-412-years-then-dies-scientists-report-262157
Anthropogenic Influence on Planet Earth
We live in a very different world from the one
we inherited from our Pleistocene forebears
Photo (1929) of New York City (previously Temperate Deciduous Forest) from Wikimedia Commons
Anthropogenic Influence on Planet Earth
“Perhaps it’s my natural pessimism, but it seems that an awfully large part of
travel these days is to see things while you still can.”
Quote from Bryson (2001, pg. 279) In a Sunburned Country; photo of polar bear from Wikimedia Commons