MA. THERESA P.
CRISPINO-CACHERO| BS BIOLOGY PROGRAM, CAS
▪Define biome
▪Enumerate the different biomes of the
world
▪Differentiate biomes in terms of their
temperature, flora and fauna
▪List down unique adaptations of flora and
fauna in different types of biomes
▪ A biome is a group of land ecosystems with similar
climate and organisms
▪ F.E. Clements and V.E. Shelford, 1939
-Combining broad-scale distribution of both plants and
associated animals into a single classification
▪ Campbell 1996: the world's major communities, classified
according to the predominant vegetation and characterized
by adaptations of organisms to that particular environment.
Three general plant forms: trees, shrubs, and
grasses.
Why are there consistent patterns in the distribution and abundance of
three dominant plant life forms that relate to climate and physical
environment?
These three forms represent different patterns of carbon allocation and
morphology
Grasses: less C to production of supporting tissue (stem) than do wood plants (shrubs
and trees), more to photosynthetic tissues (leaves)
Woody plants: shrubs allocate lower percentage to stem than trees.
Trees: more to stem, advantage of height and access to light, cost more for
maintenance and respiration.
As environmental conditions become adverse for photosynthesis (dry, low nutrient,
cold T), trees will decline in both stature and density until they are no longer able to
persist as a component of the plant community.
Within broad classes of forest and woodland ecosystem (trees are dominant or co-
dominant), leaf form is another plant characteristic.
Based on longevity of leaf
Deciduous (live for only one year or growing season)
▪ Winter-deciduous (temperate regions, low winter T)
▪ Drought-deciduous (subtropical and tropical, leaf shed on dry periods)
Evergreen (live beyond a year)
▪ Broadleaf-evergreen (tropic rainforest, no distinct growing season, year-round
photosynthesis)
▪ Needle-leaf evergreen (growing season is short or nutrient availability constrains
photosynthesis and plant growth)
Economic model to explain adaptation of leaf form: cost to produce leaf and gain
from photosynthesis.
LAND (6): RAINFORESTS, DESERTS, GRASSLANDS,
DECIDOUS FORESTS, BOREAL FORESTS, & TUNDRA
WATER (2): FRESHWATER & MARINE ECOSYSTEMS
▪An area’s biome is determined mostly by its
climate (temperature and precipitation)
▪ There are 2 main types of rain forests: Temperate Rain Forests and
Tropical Rain Forests.
▪ “Temperate”= having
moderate temperatures.
▪ Northwestern coast of U.S. is
a temperate rain forest.
▪ Receives more than 300 cm
of rain per year.
▪ Huge trees: Cedars,
Redwoods, Douglas Firs.
▪ Found in regions
close to the equator
▪ Warm and humid all
year long.
▪ Lots of precipitation.
▪ Diverse plant
growth.
▪Trees in the rain
forest form
several layers…
Canopy: A leafy roof
formed by the
tallest trees.
Understory: A
second layer of
shorter trees and
vines.
Vertical stratification of a tropic rain forest
▪ Understory plants grow well in the shade formed by the canopy,
but the forest floor is nearly dark and only a few plants live there.
▪ Desert = An area that receives less than
25 cm of rain per year.
▪ Some deserts receive NO precipitation at
all during one year.
▪ Deserts often undergo large shifts in
temperature during the course of a day.
The scorching Namib desert in Africa cools
rapidly after the sun goes down.
The Gobi desert in central Asia is cooler and
even experiences freezing temperatures in the
winter.
▪ Organisms that live in the desert must be adapted to the lack of rain
and extreme temperatures.
▪ Saguaro Cactus: Stem expands to store water.
▪ Gila monster spends weeks in its cool, underground burrows.
▪ Many other organisms are only active at night when it is cooler.
Survival of desert plants:
Adapted to scarcity of water, low primary productivity
Flowering only when moisture is present
Fast grow, flower, produce seeds and die
Deep-rooted (mesquite, taproots reach water table)
CAM pathway, special leaf structure
Survival of animals
Support a diversity of animal life (bettles, ants, locusts, lizards, snakes, birds and
mammals)
Grazing herbivores: generalists, consume a wide range of species.
Desert carnivores, such as fox and coyotes, have mixed diet include leaves and fruits.
▪ Grassland (prairie)=
An area that is
populated mostly by
grasses and other
non-woody plants.
▪ Receive 25 to 75 cm
of rain per year.
▪ Fires and droughts
are common.
Savanna: Grassland that is located closer to the equator than prairies.
▪ Savannas can receive as much as 120 cm of rain per year.
▪ In addition to grass, scattered shrubs and small trees can grow in the savanna.
▪ Grasslands are home to many of the largest animals on
Earth.
▪ Examples:
▪ Grazing by these large herbivores helps to maintain
these grasslands.
▪ Deciduous trees= Trees that
shed their leaves and grow new
ones each year (Oaks,
Maples…)
▪ Receive enough rain to support
the growth of trees and other
plants (at least 50 cm per year).
▪ Growing season is 5 to 6 months
long.
▪ Mostly contains coniferous
trees (trees that produce
their seeds in cones and
have leaves shaped like
needles). Ex. Fir, Spruce,
Hemlock…
▪ Very cold winters (a lot of
snow).
▪ Warm and rainy summers.
▪ Tundra = Extremely cold and dry
biome.
▪ Usually receives NO more
precipitation than a desert biome.
▪ Most soil is frozen all year long
(permafrost)
▪ During summer, the top layer of
soil thaws, but the rest remains
frozen. PERMAFROST
o Because rainwater cannot soak into the permafrost, there are
many shallow ponds and marshy areas of the tundra during
the summer
POLAR BEAR
WOLF
REINDEER
ARCTIC
FOX ARCTIC HARE
▪ Freshwater ecosystems include streams, rivers, ponds and lakes.
▪ Animals adapt to the
stream/river’s current
(hooks and suckers to cling
to rocks, streamline bodies).
▪ Few -plants or algae can
grow because of the strong
currents.
▪ Animals rely on seeds and
leaves to fall in the water as
food.
PONDS AND LAKES
▪ Bodies of standing or still
freshwater.
▪ Lakes are larger and deeper
than ponds.
▪ Ponds: Shallow enough for
sunlight to hit bottom (allowing
plants to grow there).
▪ Lakes (and large ponds): Too
deep for plants to grow on the
bottom, so algae grows and
floats on top of water.
Standing water: lakes and ponds
Layers of lake:
Littoral zone
Liminetic or
pelagic zone
Benthic zone
Lentic system: nonflowing water systems, such as lakes and ponds
▪ Marine ecosystems include estuaries, intertidal zones, neritic
zones, and the open ocean.
Variation in marine environments:
temperature, salinity, depth (which influence light and pressure),
currents, substrata and at the edges of ocean and tides.
Depth:
Littoral zone (intertide zone): extends between highest and lowest
tidal water levels.
Neritic zone: extends to depth of 200m, high productivity.
Oceanic zone: below neritic, sparse nutrient, low production.
Benthic zone
Seafloor below
oceanic zone.
Photic zone:
With sufficient light
for photosynthesis
Aphotic zone: no
light for
photosynthesis
Coral reefs: shallow water of
warm ocean, T>20oC year
around
very productive and high
diverse
Like tropical rain forest in
terrestrial biome
Problem: global warming,
coral bleaching
▪ Estuary: Where freshwater of a river meets saltwater of the ocean.
Intertidal Zone: The area between the highest high tide line
and the lowest low tide line.
▪ Organisms here must be able to survive the pounding waves,
water level changes, and temperature changes
▪ Ex. (barnacles, starfish, snails, clams….)
Neritic Zone: The area below the low tide line which
extends over the continental shelf.
▪ Sunlight passes through this zone, so photosynthesis can occur (plants
can grow).
▪ Coral reefs may form in water is warm.
Open Ocean: Separated into two zones:
▪ Surface Zone: The first few hundred meters deep of the ocean
(where light penetrates).
▪ Deep Zone: Below the surface zone (totally dark and home to
many BIZZARE organisms).
SURFACE
DEEP
