BIOLOGY 1

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BIOLOGY 1

• Adaptation and Competition

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Classifying Organisms

• Its likely that there are around 15 million
  living organisms!
• Only about 1.8 million of these have been named.
• In order to make it easier to study organisms,
  scientists sort them into groups this is called
  classification

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Why classify organisms?

• Scientists place similar organisms in the same
  group.
• You can usually see that these organisms have
  similar characteristics. You can also have very
  different looking organisms in the same group
  because they share similar DNA.

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The grouping system

• Kingdom
• The first group that organisms are placed in is
  a Kingdom. Examples are Animals and Plants.
• The animal kingdom has organisms as diverse as
  an elephant and a fly!

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Classifying the Tiger
Kingdom Animal
Phylum Chordates (vertebrates)
Class Mammal
Order Carnivore
Family Felidae
Genus Panthera
Species tigris
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Scientific name

• In order to give an organism its scientific
  name, you take the name of its genus and its
  species e.g. with the tiger it is Panthera tigris
• This is called the binomial system of naming
  organisms.
• The name appears in italics with the first
  letter of the genus written in a capital letter.

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Why does an organism need a scientific name?

• The binomial system of naming is used worldwide.
  Scientists, no matter where they live, would know
  that the Panthera tigris is a tiger even though
  the local name for it is different. e.g. in China
  , ?? is the name for the tiger.

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Why Latin?

• The names of the groups come from the Latin.
  This is because it was the scientist Carl von
  Linne (1707 -1778) who started the binomial
  system of classification. He was so fond of the
  Latin language that he even changed his own name
  to Carolus Linnaeus! In those days, Latin was the
  main language for teaching science. The names
  have remained to this day.

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Adaptation

• Every living organism has been adapted to live in
  a particular environment.

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Comparing two Foxes

These two foxes are closely related, but because
they have adapted to live in very different
habitats, they look quite different
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Desert Fox
Arctic Fox
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Differences between the foxes

• Size of the ear a large surface area to the
  outer ear (pinna) allows heat to radiate from the
  body and a smaller outer ear retains as much heat
  as possible.
• Body fat and thick fur coat this is more
  apparent in arctic animals that want to insulate
  their bodies as efficiently as possible.
• Colour having fur thats the same colour as
  the environment, allows animals to blend into
  their background and become more difficult to
  see. This is called camouflage.

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Plant Adaptation

• Plants are also adapted to live in their
  specific habitats. If a plant lives in a hot,
  arid (dry) habitat, then it must be very
  efficient at conserving water.

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Plant Adaptation
This is how a cactus survives the desert

• Spines instead of leaves
• succulent stem
• thick cuticle (a wax-like substance over the leaf
  surface)
• No stomata (small holes) in the leaf or stem

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These two adaptations help the organism to
survive, as producing a lot of offspring
increases the chances of survival.
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Dandelion dispersing its seeds
Insects laying a large number of eggs
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Competition

• If organisms share the same habitat and are
  dependent on the same resources, then they
  compete with each other. This can happen between
  organisms of the same species or between
  different species.

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Fight!

• It could be over
• food
• territory
• a partner

• Why do you think that these two lions are
  fighting?

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From small acorns

• The acorn shown has germinated and grown into an
  oak sapling). In the forest it will be competing
  for
• sunlight
• water
• minerals from the soil

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Predator and Prey

• A populations size depends on the number of
  predators and prey. The lynx is the predator in
  the example below, and the hare is the prey.

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• if the population of hare increases, there will
  be more food for the lynx, and their numbers
  increase.
• As more hares are eaten, their population
  decreases.
• The pattern of a predators population matches
  that of its prey, as can be seen in the following
  graph

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Predator-Prey Graph
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Pollution Indicating Species

• A Pollution Indicator is anything that shows us
  if pollution has happened.
• Species vary significantly between clean and
  polluted areas. The cleanliness of a river can be
  monitored by looking at the species of aquatic
  organisms that live in it.

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Indicator Species in Freshwater

• A large population of tubeworms in a river tells
  us that there are low oxygen levels. They are red
  in colour because they contain haemoglobin (the
  red pigment found in red blood cells) to capture
  dissolved oxygen from the water.

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red tubeworms
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• Oxygen levels can be a measure of pollution. pH
  is also measured to determine how clean water is.
  A data logger can be used to measure these
  factors.

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Data logger
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Trent Biotic Index

• This is a standard method of measuring
  pollution. It is based on the fact that different
  organisms can resist different degrees of
  pollution. The next slide shows an interpretation
  of Trent Biotic Index results.

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Trent Biotic Index Interpretation
Index State Typical Animals
XI-X Very clean Trout, salmon
VII-X Clean Fish and various arthropods
VI-VII Clean As above but fewer species
V-VI Fairly clean A few fish, freshwater fleas
III-IV Dubious As above but fewer species
II-IV Dubious As above but only fish
I-III Poor Insect larvae and tubeworms
0-I Poor Anaerobic organisms only
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Lichen

• Plants can also be good indicators of pollution.
  Lichen are very sensitive to sulphur dioxide in
  the air. They do not grow well in areas with air
  pollution.

Lichen growing n a tree in a clean air area.
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