BIOLOGY 1 Adaptation and Competition GCSE ScienceChapter 1.

BIOLOGY 1

Adaptation and Competition

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Classifying Organisms

It’s 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

KingdomThe 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 , 老虎 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 :

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 that’s 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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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

Plant AdaptationThis is how a cactus survives the desert:

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These two adaptations help the organism to survive, as producing a lot of offspring increases the chances of

survival.

Insects laying a large number of eggs

Dandelion dispersing its seeds

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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!

Why do you think that these two lions are fighting?

It could be over:

food territory a partner

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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 population’s 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 predator’s 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.

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.

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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