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Unit 4: Natural environment and Species Survival
Topic 5: On the wild side
5.1: The Biosphere

Biosphere: an area or a fraction of the Earth that is covered by living organisms.
-it is made up of many ecosystems.

An ecosystem is the community of organism interacting between themselves and the…

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Biotic factors: are dependent on the number of organisms there are compared with the resources
available.
Are density dependant

Competition:
Plants compete for space, light and minerals.
Animals compete for food, shelter and a mate.

When the fastest competitor wins:
It eliminates
dominates the other species, is called competitive exclusion.…

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Entirely new soil, surface, growth medium etc..
New land can form at river deltas, sand dunes and volcanic lava.

The first significant development is the formation of soil.
-Initial medium such as rock is eroded down over time to form most of the soil.
-external minerals can however be involved.…

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This occurs when an existing community is destroyed.
-Soil here is already present.
New species will come in due to dispersal etc...
-the species overtime will die and then carry on to develop into a new climax community.

Figure 2: Secondary Succession




Figure 2 ©Encyclopaedia Britannica D

Deflected succession is…

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(Also carnivores), eat other consumers. The carnivores at the top of the food chain are called the
top carnivores or the apex predators.


Omnivores:
Animals that eat plants and plant matter.

Figure 3: Food chain:




Figure 3 http://carrier.pbworks.com/

The energy transfer in an ecosystem can be represented in a food…

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Decomposers:
Fungi and bacteria
-feed on dead remains of organisms and excrement.
-they secrete enzymes to break down food before absorbing nutrients.




Efficiency of energy through ecosystem:
Productivity:
Dependant on how much energy is,
-captured by producers
-given to high trophic levels

Plants are not 100% efficient at absorbing light,…

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Efficiency (E):

E = (NPP
GPP )×100




Disappearance of energy:
Energy is lost as it enters higher trophic levels, but where does it go?
-not all food available is eaten: limitations of feeding methods and some parts of plants will not
get eaten.
-some energy is lost in faeces and…

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Figure 4 ©S-cool revision site




5.2: Climate Change

Evidence for Climate change:
Personal memory or `anecdotal' memory cannot be trusted to tell us if climate is changing.
We however have three different ways that we can tell climate change:
-Temperature records
-Pollen in beat bogs
-Dendrochronology.

Temperature records:
-Over time…

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One of the main things connected with Climate change is Global Warming.
-It's the gradual increase of temperature over time.

Greenhouse effect:
-The sun releases energy mostly as light.
-Most ultraviolet (UV) is absorbed by Stratosphere.
-The Earth absorbs some of this.
-The Earth warms up and radiates some of…

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Weather changes: At poles, cold, salty water sinks. Warm surface water replaces this. Melting ice
means less salinity. Slowing down of ocean currents are then a result of this. There are also
alterations in the patterns of heat and rainfall.

Coral Bleaching:
Microscopic algae live symbiotically with coral. When there…

Comments

Khadijah AG

Thanks! These are great notes

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