What part of the plant is involved inreproduction?
Carbon dioxide is generally available tomost plants from the air surrounding them.Sunshine is also generally available but insome cases plants have actively seek it:Plants that live in dense forests do haveto compete for light.Noting that most plants grow towards thelight, consider the these cases:
Many trees inthe forestsgrow very tall toget to thesunlight.
Some rainforestplants climb onothers to reach thesunlight.
Plants that live on the forest floor are adaptedto live in the shade and require less sunlight. Next, we consider a plant’s need to reproduce?
Let’s use the internet to see at how plants with flowers and cones reproduce. http://macmillanmh.com/ science/2008/student/na/ scienceinmotion/Commo n/SIM.html?Module=../Gr ade3/Chapter2- LifeCycles/Plants reproduce mainly by flowering seeds orcones.Many plant adaptations are related toreproduction but we won’t be going theretoday.
To protect themselves, plantscannot run awayfrom animals that want to eat them, such asdeer, goats, bears, insects, and rabbits. Butmany plants do have ways to protectthemselves.Some plants tastebitter.Some plants havethorns on their leavesor stems.
Some plants are poisonous and cause arash on an animal’s skin. You may befamiliar with the rash caused by poisonivy.
A plant gets water through its roots andloses water through its leaves .Many of a plant’s adaptations have todo with getting and retaining water.
Most plant adaptations seem to have comeabout because of the plant’s water supply.The rest of this presentation will be abouthow plants have adapted in the regions ofthe Earth that are defined largely theirtemperature and by how much or how littlewater they normally get.We will consider plant adaptations in:1) deserts, 2) grasslands, savannas, prairieand steppe grasslands, 3) forests, rain,deciduous and coniferous and 4) the Tundra.
First, some plant adaptations found in Desert plants.The desert regions shown in brown are dry andgenerally hot, and often have poor soil that holdslittle water.
Plants indeserts eitherhave 1) longroots thatspread outwide andabsorb a lot ofwater when itdoes rain or2) roots thatgrow deep intothe ground.
Desert plantsoften storewater in theirstems or leaves.Cactuses havestems but noleaves. Waxy coating on the leaves or stems reduce loss of water.
Hair or spineshelp shade theplant so it doesnot lose so muchwater.
Next, some plant adaptations found in Grassland plants.The grassland regions can be divided intoSavannas (tropical grassland) shown here inyellow which generally have a warm climate andalways have definite wet and dry seasons, and:
the prairie and steppes regions of the Earth.These regions, shown here in yellow have mainlydry weather, deep fertile soil, and are usually hotin the summer and cold in the winter.
Roots ofgrassland/prairiegrasses extend deepinto the ground toabsorb as muchmoisture as theycan.
Baobab tree in African grassland has huge trunk to store water during the dry season
Next, some plant adaptations found inthe forests of the world.There are three forest regions. The Tropical RainForests shown here in dark green which seldomget below 68 degrees, get about 100 inches of raineach year and have less than one inch of top soil.
Tropical rainforest trees have shallowroots because the soil is so thin.Buttresses and stilt roots help prop upplants in the shallow soil.
Many rainforest leaves have “drip tips”—apointed shape which helps drain excesswater from the leaf.
Epiphytic orchids haveaerial roots that clingto the host plant.They absorbminerals, and waterfrom the atmosphere.
Continuing with plant adaptations found inthe forests of the world.The deciduous Forests shown here in darkgreen, have four seasons with rain in the summerand rain or snow in the winter. The temperature varies from hot in the summer to below freezing in the winter. Rain is plentiful, about 30 to 50 inches per year but the trees become dormant in the winter when there is less water available.
In both the tropical rain forest and deciduousforest the trees have BIG LEAVESto absorb as much sunlight as possible.Water loss through these big leaves is not aproblem because these regions normally getadequate water.
The thin, broad, light-weight leaves of thedeciduous trees can capture a lot of sunlight tomake a lot of food for the tree in warm weather.
Most deciduoustrees have deepspreading roots—as wide as thecanopy.
When the weather gets cooler, the broad leavescause too much water loss and can be weigheddown by snow, so the tree drops itsleaves. New ones will grow in the spring.
Continuing with adaptations found intheforestsof the world we consider the Theseconiferous forest shown here in dark green.regions have short summers and long coldwinters. Temperature not hot in the summer but very cold in the winter. Moisture is generally good in the spring and summer, but freezes and is not available for the plants in the winter.
Needle-like They do not drop leavesleaves with waxy (needles) all at once in fall.covering help They are kept throughout thereduce water loss year to make food wheneverduring freezing sunshine and water areweather. available (short summers).
The triangular shape of many conifertrees helps shed heavy snow to savebranches from breaking.
Finally, we consider plant adaptations foundin the Tundra shown below in brown. This isa vast, flat, treeless Arctic region ofEurope, Asia, and North America in which thesubsoil is permanently frozen.
This plant growsThese tundra plants are in a clump tolow-growing to avoid help conservethe harsh winds. heat.
In conclusion, we have touched on just atiny sample of the remarkable adaptationsplants around the world have made in orderto survive. The thing to remember is thatplants, as well as animals, must satisfy theirneeds in order to survive, they have to adap t to conditions in their environment.