Transcript Plant Adaptations

Plant Adaptations
4th Grade Living Systems
By Brandi Crouch
In drier, temperate deciduous forests a thick bark helps to limit moisture
evaporation from the tree’s trunk.
Tropical rainforests have high
humidity, and most trees have a
thin, smooth bark.
This is probably because the
trees to not need to protect
against dryer conditions.
The smoothness of the bark
may also make it difficult for
other plants to grow on their
surface.
Lianas are climbing
woody vines that drape
rainforest trees. They
have adapted to life in
the rainforest by
having their roots in
the ground and
climbing high into the
tree canopy to reach
available sunlight.
Epiphytes are plants that
live on the surface of
other plants, especially
the trunk and branches.
They grow on trees to
take advantage of the
sunlight in the canopy.
Epiphytes: This tree has
Bromeliads and mosses living
on the surface of its bark.
The leaves of Bromeliads
form a vase to hold water.
The pineapple is an
example of a bromeliad.
Another bromeliad.
Rhizophora: In deltas
and along ocean edges
and river estuaries, trees
have adapted to living in
wet, marshy conditions.
These trees, called
mangroves, have widespreading stilt roots that
support the trees in the
tidal mud and trap
nutritious organic matter.
Desert plants have adapted to the
extremes of heat and aridity by using
both physical and behavioral
mechanisms, much like desert
animals.
Xerophytes, such as cacti, usually
have special means of storing and
conserving water. They often have few
or no leaves, which reduces
transpiration.
Xerophytes adaptations:
1. Thick cuticle.
2. Stomata hidden in crypts or
depressions in leaf surface (less
exposure to wind and sun).
3. Reduction in size of
transpiration surface (lower leaf
only).
4. Increased water storage.
5. Thicker leaves and stems, or
leaves reduced in #, or leaves
drop off during dry season.
6. Leaves covered with silvery
hairs (creates wind break & light
reflective surface).
7. Deep taproots or wide
spreading fibrous roots near the
soil surface.
Phreatophytes are another group of plants that have adapted to arid
environments. Phreatophytes, like the mesquite tree, have adapted to
desert conditions by developing extremely long root systems to draw
water from deep underground near the water table.
The Creosote Bush is one of the most successful of all desert species
because it utilizes a combination of many adaptations. Instead of thorns,
it relies for protection on a smell and taste wildlife find unpleasant. It has
tiny leaves that close their stomata (pores) during the day to avoid water
loss and open them at night to absorb moisture. Creosote has an
extensive double root system -- both radial and deep -- to accumulate
water from both surface and ground water.
Some plants, such as
the Ocotillo, survive by
becoming dormant
during dry periods, then
springing to life when
water becomes
available.
The Ocotillo also has a
waxy coating on stems
which serves to seal in
moisture during periods
of dormancy.
Another example of plants that
utilize dormancy as a means of
evading drought are bulbs,
members of the lily family. The
tops of bulbs dry out completely
and leave no trace of their
existence above ground during
dormant periods.
The Desert Lily is found at a
depth of 18 inches or more.
Adequate winter rains can rouse it
to life after years of dormancy.
Desert plants must act
quickly when heat,
moisture and light inform
them it's time to bloom.
Ephemerals send out
flower stalks in a few
days.
Ephemerals such as the
Desert Sand Verbena
usually germinate in the
spring following winter
rains. They grow quickly,
flower and produce
seeds before dying and
scattering their seeds to
the desert floor.
The Desert Paintbrush
is another ephemeral
that quickly blooms
and scatters its seeds
when it is active.
Supportive adaptations: many plants have developed adaptations that
help them be more supported in order to grow taller and stronger.
Some tropical trees have buttress roots, which are roots that come out
from the lower part of the trunk and grow into the ground.
Prop roots: Some trees grow in very unstable soil, and the complex
prop root system helps keep the tree stable in an unstable
environment. You can find an example of prop roots when looking at
red mangroves.
Prop roots on corn.
Epiphytes and vines also have special roots that help them grab onto a
tree’s bark and stay put.
Defensive adaptations:
Plants as we know have
evolved ways to defend
themselves by using sharp
spines, thorns or hairs;
cellulose that makes them
hard to digest, or creating
toxic chemicals. Another
unusual way some plants
have evolved to defend
themselves is through
mimicry - that is they evolve
to look like another plant
that is poisonous and
animals are fooled into
believing that they are
poisonous.
Because weather conditions in the
arctic and alpine tundra are
unpredictable, plants need to adapt
to all sorts of weather. Being close to
the dark, warmth-absorbing soil
helps to keep plants from freezing.
Instead perennials are more hardy of a plant for the tundra. They are
plants which do not die in the winter because they keep their leaves,
shoots and sometimes just roots in the ground. They quickly grow
when the short growing season starts.
Another way plants have adapted is by how their seeds are dispersed.
Some seeds hitch a ride on passersby using tiny hooks that snag on fur or
clothing, only to be brushed off later far from the parent plant.
Other plants, like the dandelion have seeds better adapted to be caught by
the wind and transported to another location.
The seeds of maple trees are also very
aerodynamic. They mimic wings.
Aquatic plants like this fringed
water lily have not needed
adaptations for strengthening
themselves. They are
supported by the water they
live in. They also do not need
as many roots since they live
in the water.
Many aquatic plants have
very specialized leaf
shapes. The submerged
leaves are often very
divided. This has the
advantage of creating a
very large surface area for
absorbing water and for
photosynthesis.
Pitcher plants
(nepenthes) are named
after an unusual
adaptation. They have
a structure shaped like
a pitcher or vase that
acts as a trap. The trap
contains a fluid that the
plant produces. This
fluid is used to drown
the prey. The lower part
of the trap contains
glands which absorb
nutrients from captured
prey.
That’s right! Pitcher
plants are carnivorous.
“There is no doubt
that tropical pitcher
plants (Nepenthes)
eat prey: they attract
it, kill it and absorb
the products of
digestion.”
-June 2000, The Enduring
Controversies Concerning
the Process of Protein
Digestion in Nepenthes
(Nepenthaceae),
International Carnivorous
Plant Society Newsletter.
http://www.carnivorouspla
nts.org/cpn/samples/Scien
ce292Digest.htm