Showing posts with label Needleleaf biome. Show all posts
Showing posts with label Needleleaf biome. Show all posts

Wednesday, July 4, 2012

Kingdom Plantae


Kingdom Plantae contains nearly 300,000 different kinds of plants. They also place the macroscopic, multicellular brown algae (Division Phaeophyta) and red algae (Division Rhodophyta) in the Kingdom Plantae.Although this does not make it the largest kingdom, many might argue that it is the most important one.In the process known as "photosynthesis ", plants use the energy of the Sun to make food and oxygen. This complex chemical reaction provides nearly all the oxygen in Earth's atmosphere and all the food required by living things. Although some protists and bacteria are capable of performing photosynthesis, plants do most of the photosynthesis on Earth.
                 The ancestors of plants first appeared in the seas nearly 700 million years ago. Another 265 million years passed before the first plants appeared on land. These early land plants looked very different than the plants you're familiar with today. In fact, many of them didn't even have roots, stems, or leaves! Since then, plants have taken on a variety of forms and are found in most places on Earth.
General Characteristics
 
A. Contain chlorophylls a and b.
B. Cell walls made of cellulose.
C. Have tissues and organs (roots, stems and leaves).
 
 Evolution of Plants
A. Evidence that plants evolved from algae
1. Green algae and plants both have chloroplast with chlorophylls a and b
2. Both have cell walls made of cellulose.
3. Both form starch as stored glucose.
4. Both demonstrate alternation of generations

Problems with life on land
A. Dehydration
1. Adaptations
a) Roots, vascular tissue, cuticles and bark
B. Support
1. Adaptations
a) Stiffer, thick cell walls; wood
C. Distribution of gametes and/or spores
1. Adaptations
a) Water tight seeds and/or spores.
b) Spores lighter than air.

Classification of Plants

A. Phylum Bryophyta 
  • Primitive
  • Lack vascular tissue
  • Lack true roots
  • Mosses and liverworts (Hepatophyta)
B. Super Phylum Tracheophyta
  • More advanced than Bryophytes
  • Contain vascular tissue
C. Phylum Pterophyta 
  • Reproduce by spores
  • Leaves generally grow from underground stems
  • Ferns and horse tails
D. Phylum Coniferophyta
  • Produce naked seeds in cones
  • Many are evergreens
  • Produce soft wood
  • Needle like leaves
  • Redwoods, pines, cypress and junipers
E. Phylum Anthophyta
  • Flowering plants
  • Either herbaceous or hardwoods
  • Most advanced of all plant forms
a) Class Monocotyldonae (Monocots)
  • Seeds contain one cotyledon
  • Leaves have parallel veins
  • Flower parts are usually in multiples of 3
  • Lack cambium
  • In the stem, vascular bundles are scattered
  • Generally wind pollinated
  • All are herbaceous with a few exceptions
b) Class Dicotyledonae (Dicots)
  • This class is now called Eudicotyledonae
  • Seeds contain two cotyledons
  • Leaves have netted veins
  • Flower parts are usually in multiples of 4 or 5
  • Have cambium
  • Vascular bundles are arranged in a cylinder, in the stem.
  • Generally pollinated by animals.

Tuesday, April 10, 2012

Tundra

Tundra Biome



              In the very cold places of the world, survival isn't easy. The soil is frozen, its top surface thawing only during summer, and no trees can grow. Yet plants and animals that are adapted for the harsh conditions thrive. This biome is called tundra. Most of the world's tundra is found in the north polar region. It is called Arctic tundra. There is a small amount of tundra on parts of Antarctica that are not covered with ice. Plus, tundra is found on high altitude mountains and is called alpine tundra.


             Permafrost is the term given to frozen soil. During the winter months, permafrost reaches the surface of the tundra. It is very cold during the winter, with temperatures reaching -60 degrees Fahrenheit (-51 degrees Celsius). Very few animals are active in these harsh conditions.


              In the summer time, the tundra changes. The Sun is out almost 24 hours a day, so the tundra starts to warm up. The permafrost melts at the surface, and plant life grows. However, the permafrost only disappears for a few inches below the surface. There isn't enough soil for trees to grow, so only small plants are found in the tundra.


          At the same time, a variety of animals come out to feast on the plants. Insects come to feed on the animals, and birds appear to enjoy the insects.


Characteristics of tundra include:
  1. Extremely cold climate

  2. Low biotic diversity

  3. Simple vegetation structure

  4. Limitation of drainage

  5. Short season of growth and reproduction

  6. Energy and nutrients in the form of dead organic material

  7. Large population oscillations
Tundra is separated into two types:

Arctic tundra

                    Arctic tundra is located in the northern hemisphere, encircling the north pole and extending south to the coniferous forests of the taiga. The arctic is known for its cold, desert-like conditions. The growing season ranges from 50 to 60 days. The average winter temperature is -34° C (-30° F), but the average summer temperature is 3-12° C (37-54° F) which enables this biome to sustain life. Rainfall may vary in different regions of the arctic. Yearly precipitation, including melting snow, is 15 to 25 cm (6 to 10 inches). Soil is formed slowly. A layer of permanently frozen subsoil called permafrost exists, consisting mostly of gravel and finer material. When water saturates the upper surface, bogs and ponds may form, providing moisture for plants. There are no deep root systems in the vegetation of the arctic tundra, however, there are still a wide variety of plants that are able to resist the cold climate. There are about 1,700 kinds of plants in the arctic and subarctic, and these include:
  • low shrubs, sedges, reindeer mosses, liverworts, and grasses

  • 400 varieties of flowers

  • crustose and folios lichen
                   All of the plants are adapted to sweeping winds and disturbances of the soil. Plants are short and group together to resist the cold temperatures and are protected by the snow during the winter. They can carry out photosynthesis at low temperatures and low light intensities. The growing seasons are short and most plants reproduce by budding and division rather than sexually by flowering. The fauna in the arctic is also diverse:
  • Herbivorous mammals: lemmings, voles, caribou

  • Carnivorous mammals: arctic foxes, wolves, and polar bears

  • Migratory birds: ravens, snow buntings, falcons, loons,

  • Insects: mosquitoes, flies, moths, grasshoppers

  • Fish: cod, flatfish, salmon, and trout
                  Animals are adapted to handle long, cold winters and to breed and raise young quickly in the summer. Animals such as mammals and birds also have additional insulation from fat. Many animals hibernate during the winter because food is not abundant. Another alternative is to migrate south in the winter, like birds do. Reptiles and amphibians are few or absent because of the extremely cold temperatures. Because of constant immigration and emigration, the population continually oscillates.

Alpine tundra

   
                           Alpine tundra is located on mountains throughout the world at high altitude where trees cannot grow. The growing season is approximately 180 days. The nighttime temperature is usually below freezing. Unlike the arctic tundra, the soil in the alpine is well drained. The plants are very similar to those of the arctic ones and include:
  • tussock grasses, dwarf trees, small-leafed shrubs, and heaths
Animals living in the alpine tundra are also well adapted:

  • Mammals: pikas,, mountain goats, sheep

  • Birds: grouse like birds

  • Insects: spring tails, grasshoppers ,beetles

Saturday, May 14, 2011

Needleleaf biome



              Needleleaf forest is composed largely of straight trunked, conical tress with relatively short branches, and small, narrow, needlelike leaves. These tress are conifers. Where evergreen, the needleleaf forest provides continues and deep shade to the ground so that lower layers of vegetation are sparse or absent except for a thick carpet of mosses in many places. Species are few and large tracts of forest consist almost entirely of but one or two species.

              Needleleaf evergreen forest extends into lower latitudes wherever mountain range and high plateaus exist. Thus in western North America this formation class extends southward into the United States on the Cascade, Sierra Nevada, and Rocky Mountain ranges and over parts of the higher plateaus of the southwestern states. In Europe, needleleaf evergreen forests flourish on all of the higher mountain ranges, and well into Scandinavia.

Taiga

            The taiga is the biome of the needleleaf forest. Living in the taiga is cold and lonely. Coldness and food shortages make things very difficult, mostly in the winter. Some of the animals in the taiga hibernate in the winter, some fly south if they can, while some just cooperate with the environment, which is very difficult.

           Temperature range in the summer gets as low as -7° C (20° F). The high in summer can be 21° C (70° F). The summers are mostly warm, rainy and humid. They are also very short with about 50 to 100 frost free days. The total precipitation in a year is 30 - 85 cm (12 - 33 in) . The forms the precipitation comes in are rain, snow and dew. Most of the precipitation in the taiga falls as rain in the summer.

          The main seasons in the taiga are winter and summer. The spring and autumn are so short, you hardly know they exist. It is either hot and humid or very cold in the taiga.

          There are not a lot of species of plants in the taiga because of the harsh conditions. Not many plants can survive the extreme cold of the taiga winter. There are some lichens and mosses, but most plants are coniferous trees like pine, white spruce, hemlock and douglas fir.

         Evergreens in the taiga tend to be thin and grow close together. This gives them protection from the cold and wind. Evergreens also are usually shaped like an upside down cone to protects the branches from breaking under the weight of all that snow. The snow slides right off the slanted branches.

         The taiga is susceptible to many wildfires. Trees have adapted by growing thick bark. The fires will burn away the upper canopy of the trees and let sunlight reach the ground. New plants will grow and provide food for animals that once could not live there because there were only evergreen trees.

Temperate coniferous forest

         Temperate coniferous forest is a terrestrial biome found in temperate regions of the world with warm summers and cool winters and adequate rainfall to sustain a forest. In most temperate coniferous forests, evergreen conifers predominate, while some are a mix of conifers and broadleaf evergreen trees and/or broadleaf deciduous trees. Temperate evergreen forests are common in the coastal areas of regions that have mild winters and heavy rainfall, or inland in drier climates or mountain areas. Many species of trees inhabit these forests including cedar, cypress, douglas-fir, fir, juniper, kauri, pine, podocarpus, spruce, redwood and yew. The understory also contains a wide variety of herbaceous and shrub species.


           Coniferous trees are also known as evergreens. They have long, thin waxy needles. The wax gives them some protection from freezing temperatures and from drying out. Evergreens don't loose their leaves in the winter like deciduous trees. They keep their needles all year long. This is so they can start photosynthesis as soon as the weather gets warm. The dark color of evergreen needles allows them to absorb heat from the sun and also helps them start photosynthesis early.

A pine forest is an example of a temperate coniferous forest

          Structurally, these forests are rather simple, generally consisting of two layers: an overstory and understory. Some forests may support an intermediate layer of shrubs. Pine forests support an herbaceous understory that is generally dominated by grasses and herbaceous perennials, and are often subject to ecologically important wildfires.