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AS Biology notes: Biodiversity and Natural Resources

>What is a species?
`A species is a group of organisms with similar morphology, physiology, and
behavior, which can interbreed to produce fertile offspring, and which are
reproductively isolated (in place, time or behavior) from other species.'
[Identifying species can be done through…

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Is the mechanism by which organisms change over time as they adapt to
changing environments. As a population increases in size organisms will die/ fail to
reproduce due to competition for resources e.g. food/space, also could be due to
disease/ extreme environmental conditions. `Struggle for existence' = striving for
survival.…

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italics and the genus always starts with a capital letter and species lowercase. For
example Homo sapiens


>Sorting and Grouping
Classifying organisms based on shared features is known as taxonomy.
Linnaeus created the first classification system, grouping organisms according to their
visible similarities and differences. A taxonomic hierarchy is created…

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* Random mutations ~ changes in DNA sequences in cells= new alleles





Measuring Biodiversity
>Species Richness
Counting the number of species present in a given habitat. E.g. Wood in
southern England (S.E) = 25 butterfly species, but similar area in south America (S.A)
= 10x as many. So S.A. has…

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>Cell Walls Cellulose
A plants strength = partly from cellulose walls of plant cells and the `glue' that holds
them together.
(Are two forms of glucose: alpha and
beta)
2 beta glucose joined (one
rotated 180o) in condensation reaction ­
in OH groups
glucose chain = molecule of
cellulose

Cellulose=…

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Tubes for transport and strength
Some cells must be stiffened and some allow water and minerals to pass from roots to
leaves are 2 specialized types of cells to do these functions:
xylem vessels : form tubes for transport, and stiffened cell walls help support
the plant
sclerenchyma fibres: columns…

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Xylem vessels also transport minerals ­ inorganic ions.
Movement of water = mass flow system for transport of inorganic ions. Absorbed
through roots by active transport.

Nitrate ions= needed for amino acids in order for plant to grow (cytoplasm is largely
made of proteins, also chlorophyll, nucleic acids, ATP contain…

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Could treat condition called dropsy/Oedema (now) where fluid accumulates in body's
tissues caused by heart/kidney problems fast irregular heartbeat=symptom

William Withering caused it to be an accepted form of medicine steps: ...
1.) Withering tested the drug on patients with the disease and recorded side affects
2.) Used standard procedure…

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In flowering plants the ovule is fertilized by the nucleus from the pollen grain and
develops into the seed.
the outer layer is lignified forming a tough seed coat protecting ambyo
the surrounding ovary develops into fruit important role in seed dispersal
the stored food remains outside embryo in endosperm…

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Definition: It is meeting the needs of the present generation without compromising
the ability of future generations to meet their needs.

Use of oilbased plastics and fuels isn't sustainable because:
~ burning oilbased fossil fuels releases CO2 into atmosphere
~Oil reserves will eventually run out
~Plastics generate nonbiodegradable waste waste…

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