Download Chapter 21 The Living Planet (SP09)

Chapter 21 The Living Planet (SP09)
Purpose of this chapter:
• To discover patterns in where certain species live.
• To better understand how organisms interact with their
surroundings
• To see the hand of a creative God in the beauty and intricacy of
His creation.
21.1 The Patterns of Life
Activity 21B
biosphere - the part of the earth and its atmosphere in which living
organisms exist or that is capable of supporting life.
biome – a large geographical land area that is characterized by
having the same general kinds of plants and animals throughout.
dominant plant species – the most abundant type of plant in a
particular location
e.g. Consider the prairies of Alberta, Saskatchewan and the
USA which are grasslands – even though the span thousands
of square kilometres, they are very similar. As a matter of fact,
grasslands throughout the Earth are all very similar to each
other.
1
ecosystem – a community of organisms (of different species) that
interact among themselves and with their environment.
Review Science 7:
What do we mean by the words:
• biotic
• abiotic
• interact
Majour biomes of the world.
Together, the ten biomes shown in the
above map make up the biosphere.
Even though plants are a good way to identify biomes, an even more
important feature is the climate: this is because the climate is the
2
most important factor determining what kind of plants can grow in a
certain area.
climatograms (or climatographs) - are graphs that show the
monthly precipitation and temperature variations over the course of a
year for a certain location. These two factors are the most
important features of climate. The red line at the top traces the
temperature change and the blue bar graph tells what the
precipitation is.
This climate graph is for Manila, Philippines. Using the clues
Of temperature and precipitation, what
can you tell me about the plant life in this area?
Activity 21C
3
Adaptations to Precipitation
adaptation – a feature that helps an organism survive in its particular
environment.
There are two biome extremes when we talk about precipitation:
• deserts – where there is less than 25 cm of water for an entire
year.
• rain forests – where there is more than 150 cm per year.
Consider the above pictures and answer the following questions:
1. What problems of survival must the plants in each situation
overcome?
2. How do they overcome these problems?
3. What can you tell me about the number of animals in these
biomes based on the available plant life?
Think about it!
Desert –
• must compete for water efficiently
• must store water for times when it is scarce
4
• must keep water from transpiring (evaporating from it’s
leaves) too fast
• must protect itself from animals who want to get water for
themselves.
Rain forest –
• must compete for sunlight; water isn’t an issue!
Think about it!
• If plants photosynthesize food and make it available to
other living things; which biome will have the most
available food?
• Which biome can support the most animal life?
Adaptations to Temperature
Plants don’t have as big a problem with high temperatures as they do
with low temperatures. As long as there is enough water, plants can
survive in very warm climates.
• Consider tropical rain forests, which are very warm. Every
day huge amounts of water transpire from the leaves of
plants. This is not a problem because the water is just
sucked back up into the plant. No problem! Winters here
are also pretty warm.
• Consider trees in Kelowna. Sure, its warm in summer, but
what about our winters?
Think about it!
5
• What could happen if there was water in a plant if the
temperature went below 0oC?
Okay , we have two types of trees. Using page 465 of your text, tell
how both types of trees deal with winter:
¾ deciduous
¾ coniferous
dormant – when an organism goes through a period of inactivity.
21.2 Biomes of BC
In the areas provided below, describe what this biome is like. Make
sure you tell where you might find it, what the temperature and
precipitation is like, what kind of plants and animals live here etc.
6
Four of BC’s majour biomes are:
• Alpine tundra
7
• Northern coniferous forest
8
• Desert
9
• Temperate rain forest
tree line – the high altitude limit of the northern coniferous
forest…this is the line above which climatic conditions won’t allow
trees to grow.
10
transition zone – the border area of the tree line between full trees
and bare rock where tree growth is stunted and only live as short,
wind-blown shrubs.
How can there be a desert in Canada?
Cloud drops all its water.
Air warms and dries as it
descends
Rain forest
Desert
11
21.3 Biomes and Change
succession – the gradual change in the organisms that make up a
community. From bare ground, the first organisms (pioneer
organisms) to inhabit the area are normally lichen, mosses and
grasses. These trap sand particles and donate organic matter to
produce the area’s first soils. This prepares the way for the next step
organisms, small shrubs and trees, which are deciduous. In time
conifers take over and produce acidic soli conditions which inhibit
other trees from growing. This conifer forest is considered the climax
community because no further changes take place.
12
21.4 Human Impact on Biomes
The majour human impacts include
1. Introduction of foreign species of plants or animals
2. Introduction of artificial communities
3. Pollution of biosphere
4. Harvesting of earth’s resources
(FAPH – a memory aid)
1. Introduction of foreign species of plants or animals. When
seeds from another location are brought into an area for the
first time, they may have no natural enemies or controls. They
can then reproduce unchecked, multiplying faster and faster
and may take over the area.
Eg. Rabbit in Australia, Starlings in North America.
2. Introduction of artificial communities. This refers to the
planting of gardens and agricultural fields. This interrupts
natural succession in the area. If the fields were left alone,
weeds (a pioneer species) would begin to grow and in time, it
would be overrun with new growth. In time it would return to the
natural cycle and ultimately develop a climax community.
3. Pollution of biosphere. This refers to the chemical wastes that
we introduce into the soil, water and air. Their build up is toxic
and damaging to the environment…possibly beyond repair.
13
4. Harvesting of earth’s resources. As forests are cut down for
lumber or fish and animals are hunted to excess, the delicate
natural balances of the environment are disrupted. Each
organism plays an important role in the complex food web and
the loss of one member can severely affect several other
members …possibly the entire biome. What would happen if
suddenly there were no mouse predators in North
America?...we would be overrun with mice, our crops would all
be eaten and diseases carried by mice would flourish.
***A word on global consumerism. Be informed. What you buy from
China may have been at the cost of a forest being cut down for
materials etc.
14