biology revision notes

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  • Created by: annum
  • Created on: 05-02-13 17:15

·         Classification is when animals are put into groups because they have the same characterises

·         There are 5 kingdoms animalia, Plantae, fungi, prokaryote& protoctista

·         Multicellular is animals with more than one cell

·         Binomial classification is important because it can:

·         clearly identify species

·         study and conserve species

·         Target conservation efforts.

·         Scientists do not classify a virus as a living thing. This is because:

it does not show all seven processes for life

When it enters a cell it changes the way a cell works so it can make copies of the virus.

ü  The vertebrates are animals with a backbone invertebrates are animals without a backbone. Scientists separate this group into smaller groups because of their features:

·         how the animal takes in oxygen – lungs, gills or through the skin

·         thermoregulation – maintains own temperature (homeotherms) or temperature varies with surroundings (poikilotherms)

·         Reproduction – internal or external fertilization, lay eggs or give birth to live young 

·         The protoctista are usually unicellular with a nucleus

 

·         Oviparous means to lay eggs

 

·         Birds lay eggs and so do not give birth to live young

 

·         A poikilotherms temperature varies with surroundings. 'Homeotherms' means maintaining own temperature

 

·         Viviparous is when living things give birth to live young

 

v  What is a species?

Organisms of the same species:

·         have more characteristics in common than they do with organisms of a different species

·         Can interbreed to produce fertile offspring.

Sometimes classification can be complicated by:

·         variation within a species

·         hybridization

·         Ring species –

·         Organisms are adapted to survive in different conditions. Over many generations, these adaptations have come about through variation. Variation involves small changes between organisms which may allow that organism to compete better for survival. Variation can have environmental or genetic causes.

·         Organisms living in different habitats need different adaptations.

Variation

·         Human height, weight & foot length are examples of continuous variation.

·         Human eye colour, blood group, eye colour are examples of  discontinuous variation

·         The independent variable is length of the pea pod.

·         The dependent variable is the number of peas.

·         Variation in a characteristic that is a result of genetic inheritance from the parents is called inherited variation.

·         Evolution is biological evolution is change in the characteristics of living organisms over generations an example of this is fossil fuels

Evolution

v  Evolution has taken place over millions of years and scientists believe this is the reason why all living things on Earth exist today. There are different views and theories about the origin of life and the evolutionary process. English naturalist Charles Darwin wrote one of the first major scientific books on this subject.

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