Module 4 chapter 10


10.1 Classification

Classification is the name gven to the process of sorting living organisms into groups that have similar features.

There are seven hiarachy in this process referred to a Taxonomic Groups. this groups are

  • kindom
  • Phylum
  • class
  • order
  • family
  • genus  (will have capital letter in binomial naming system )
  • species

Scientist classify animals in a single classificiation system to predicts characteristics, identify animals, find evolutionary links and to be able to share data.

A species is when two organisms can reproduce and produce fertile off springs. They have a binomial name so that scientist internatinally can refer to them with out complications.

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10.2 The Five Kindoms Part 1

The 5 kindoms include Prokaryotae (only prokaryote), Protoctista, Fungi, Plantae, Animalia.

  • Prokaryotae (bacteria) are unicelluar, no nucleaus or membrane bound organelles, nutrients are absorbed.
  • Protoctista (eg Amoeba) maily unicelluar, had nucleus and membrane bound organelles, some have chloroplasts, move by cillia and flagella or amoeboid mechanisms, nutrients are aquired by phtosynthsis (autotrophic) or ingestion of other organisms(hetrotrophic)
  • Fungi (eg yeast) can be unicellular or multicellular, cell wall of chitin and has nucleus+ membrane bound organelles, no chloroplast or chlorophyll, have a body made of hyphae, absorbes nurtrients maily from decay (saprophytic), store food as glycogen.
  • Plantae (eg Oak tree) multicellular, has nucleus membrane bound organelles and a cell wall, contains chlorophyll, dont move, use photosynthesis for nutrients, stores food as starch.
  • Animalia (eg mammels) multicellular, no cell wall but has nucleus and membrane bound organelles, no chlorplast, move with cillia flaggella and muscular organs, nutrients from ingestion, food stored as glycogen.
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10.2 The Five Kindoms Part 2

Domains are further levels of classification at the top of the hiarchy. The 3 dimains are Archaea, Bacteria and Eukarya. These contain unique forms of rRNA

  • Eukarya contains 80s ribsomes, RNA polymerase( responisble for mRNA transcription) contains 12 proteins,
  • Archaeacotains 70s ribsomes, RNA polymerase contains bwteen 8 and 10 proteins and is very similar to eukaryotic ribosomes.
  • Bacteria contains 70s ribosomes, RNA polymerase contains 5 proteins.

In the new system there are 6 kindoms as prokayoae is split into two ( Eubacteria and Archaebacteria) this is due to their chemical make up eg Eubacteria contains peptidoglycan in their cell wall but Archaebacteria does not)

Archaebacteria are known as ancient bacteria and can live in exstreme enviroments eg anaerobic conditions and highly acidic enviroments

Eubacteria are known as true bacteria and are found in all enviroments and are the most common.

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10.3 Phylogeny

Phylogeny is the name given to the evolutionary relationship between organisms.

Phylogenetic trees is a diagram to represent the evolutionary links between organsims showing how different species have eveolved from the same ancestor. This shows how related organisms are through out evolution.

The trees is made up by looking at characteristics and genetic make up of organisms much of the evidence has been gains hrough fossils.

Advantages of phylogentic classification

  • can confirm the classifcation groups are correct or causes changes to them for example the dolphic was classed as a fish but through looking as the gentic make up they found it was a mammel.
  • produces a continuous tree and doesnt forces scientist to classify organsims into a group they dont quite fit.
  • the trees shows the level of diversity with in families.
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10.4 Evidence for Evolution

Palaentolgy is the study of fossilsand fossil records.

  • You can form a pattern of oldest and youngest  and see the the changes of an organism over time also showing us how closely related organisms are.
  • fossils of bacteria are found in very old rocks and vertebrate are found in younger rocks which supports that simple goranisms evolved into more complex one.
  • plant fossils are found older than anmals supporting that animals need plants to survive.
  • Fossils allow us to study living and exstinct organisms.

Comparitive Anatomy is the study of similarities and differences between organsism anatomy.  Homologous structure is when the structure of bone looks completely different in different organisms but have the same underlying function. This shows divergent evolution which describes how a common ancestor has evolved to create different species.

Embryology is looking at organisms early forms as an embryo. many organisms look nealr indistingisable as embyros suggesting that there is a common origin and ancestot that evolved to have different traits.

Comparitive Biochemistry is the similarities and differences between the chemical makeup of organisms. This looks at the order od DNA bases. The number of differences are plotted against the molecules  that undergoes neutral base pair sunstitutions( changes that do not affect a molecules funtion) to estimate the point at which two species last shared a common ancestor. The closeer the relationship the more simliar DNA.

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10.5 Types of Variation Part 1

Types of Variation.

  • Variation between species is known as interspecific variation.
  • Variation within the same species is known as intraspecific variation.

Genetic Causes of Variation:

Difference in genetic material that are inherited from parents can lead to genetic variation.

  • Alleles. Genes have different alleles taht code for different characteristics. Depending on which allels pair up depends on the outcome of the characteristic.
  • Mutations. Changes to the DNA sequence can be caused by mutations. This leads to changes in which proteins are coded for that affect physical and metabolic chracteristics of an organism.
  • Meiosis. Gametes (sex cells) are produced by meiosis. Variation occurs in meiosis because of independant assortment and crossing over.
  • Sexual Reproduction. Due to an offspring  sharing both parents genetic their genetic will overall be differen to each parent.
  • Chance. During sexual reproduction variation is a result of chance as to which two gametes combine. This causes variation between siblings.
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10.5 Types of Variation Part 2

Enviromental Causes of Variation

  • Envirtomental causes of variation have a big impact on plants because of the lack of mobility. For example if there are two plant bushes  one will grow tall if it is in the shade.
  • Another form of enviromental variation is scars created by the enviroment as these are not inherited.

Interaction from Genetics and Enviroment

  • In many cases variation is caused by genetics interacting with the enviroment. For example you are more likely to be tall if you parents are however with a poor diet you will only be average.
  • This makes it very difficult to investigate causes of variation in a paticular case. To over come this you can use twins studies as they share 100% of their genetic information.
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10.6 Representing Variation Graphically Part 1

Discontinuous Variation

  • These are characteritsics that can only reslt in certain values. There are no inbetween values. For example sex is either male or female.
  • This type of variation is represented usig a bar chart

Continuous Variation

  • This is a characteristic that can be with in a range between one etsreme to another. An example of this is height. This type of characteristics are controlled by multiple genes(Polygenes)
  • This type of variation is collected in a frequency table and represemted on a histogram.

Normal Distrabution curve

A graphs that shows a 'bell shaped curved' is a normal distrabution. Characteristics include

the mean, mode and median are the same. This means 50% of the results are high than the mean and 50% are above the mean. Majority of the values are similar to the mean value.

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10.7 Adaptions Part 1

What are Adaptions

Adaptations are characteristics that increase an organism's chances of survival. 3 Types of adaption:

Anatomical Adaptations:

  • Body Covering like hair, spines , feathers, shells and scales that help for things like flying and protection against preditors.
  • Camouflage outer colour of the anymal allows it to blend into the enviroment.
  • Teeth the shape and type of teeth relate to their diet.
  • Mimicry Copying other animals apperance and sounds make harmless animals seem stronger and scary to preditors into thinking it is poisonous.

Marram grass live on sandoms and have adaptions to reduce the rate of transpiration such as being curled to reduce surface area exposed and to protect the tissue from wind. Another adaptation is hair on the inside of the curl to trap moisture. This reduces transpiration as it reduces the diffusion gradient. Marram grass stomata is suken to reduce water loss while open. Finally, Marram grass has a thick waxy cuticle to reduce water loss by evaporation.

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10.7 Adaptions Part 2

Behavioural Adaptions:

  • Survival behaviours playng dead when seen.
  • Courtship behaviours that allow animals to attract a mate by showing feathers, dancing and singing.
  • Seasonal behaviours these are thigs that allow animals to survive a change in weather such as migration and hibernation

Behaviour adaptions fall into two catagories (innate and learned). Howver manny behavuiours are a mixture of both.

Pysiological Adaptions:

  • Poison production reptiles produce venon to catch prey and plants produce poison to be pretected from being eaten
  • Antibiotic production some bactria can produce antibiotics to kill other species of bacteria
  • Water holding when they can hold water in their body to increase survival in a desert.

Other physiological adaptions include blinking, temperature regulation and reflexes.

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10.7 Adaptions Part 3

Analogous structure are features that have adapted to perform the same fucntion but have different genetic origins.

Convergent evolution is when unrelatted species being to share similar traits due to living in a smilar enviroment or other selection pressures.

Examples include:

  • Marsupial and placental mice: they both are small, agile climbers.
  • Flying phalangers and flying squirrels : both are gliders that eat insects and plants.
  • Marsupial and placental moles: both burrow an have streamline bodies and modified forelimbs for digging.
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10.8 Changing Population Characteristics

Natural selection

All organism are exposed to selection pressures which are factors that affects an organism chnace of survival  and reprduction.

Natural selection follows certain steps:

  • Genetic variation with in a species.
  • Organisms with whom are better adapted to survive selection pressures out compete others in the populations.
  • The organisms that survive pass on their advantagous characteristics to their off springs.
  • This proccess is repeated until the frequency of the advantagous chracateristic increases in frequency becoming the majority trait.

Exampls of modern evolution:

  • Antibiotic resistant bacteria
  • peppered moths
  • Sheep Blowflies
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10.6 Representing Variation Graphically Part 2

Standard Deviation: This is a measurement of how spread out data is.



Spearman Rank: This is used to consider the relationship between two set sof data.




Studant T-Test : This is used to compare the mean data values of two populations.




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