4.3.4-.5(Phylogeny and natural selection)

State the 2 types of classification systems

• Natural

• Artificial

What is meant by artificial classification

• Placing organisms into groups for purposes of convenience. groups usually based on a few or a few easily observed features

Are evolutionary relationships taken into account in natural classification and artificial classification?

• Artificial does not

• Natural does

can groups change in artificial classification and natural classification change?

• In artificial they do not change

• In natural they can change with advancing knowledge

How much useful information is provided from natural and artificial classification?

• Limited information is provided from artificial classification

• A lot of useful information is provided from natural classification

compare artificial and natural classification

• Artificial uses a few characteristics. Natural uses many

• Artificial does not use evolutionary relationships. Natural takes into account evolutionary relationships between animals

• Artificial is stable. Natural changes with advancing knowledge

• Artificial provides limited information. Natural provides a lot of useful information

What is phylogeny?

• It is the representation of evolutionary history and relationships between groups of organisms. Results are represented in a phylogenetic tree

What are monophyletic organisms

• They are organisms that have evolved from the same common ancestor

Describe how researchers can group organisms into a phylogenetic tree

• Look at common morphological traits and DNA or amino acid sequences to show relationships between organisms

What are clades

• They are also known as a monophyletic group

• It is a group of organisms composed of a common ancestor and all its lineal descendants - on a phylogenetic tree

what is cladistics

• Method of hypothesizing relationships among organisms 

• The basis of cladistics analysis is data on the characteristics, or traits, of the organisms in which we are interested in

  Traits could be anatomical and physiological characteristics, behaviours or genetic sequence

Name the 2 evolutionary scientists 

• Darwin

• Wallace

Describe what Darwin observed to prove natural selection

• There is variation in the characteristics of the same species

• Some of these characteristics can be passed on from one generation to the next

• Organisms produce more offspring that survive

• Individuals that are best adapted to their environment are more likely to survive

Explain how Darwin explained his observations

• Individuals within a population show variation in their phenotypes. 

• Selection pressures create a struggle for survival.

• Individuals with advantageous adaptations are more likely to survive, reproduce & pass on advantageous alleles to their offspring. 

• Over time the frequency of the advantageous allele increases. 

• Over generations this leads to evolution as the advantageous adaptations become more common.

Describe how Wallace contributed to the Theory of evolution

• Wallace independently came up with the idea of natural selection. 

• He & Darwin published their papers on evolution together. 

• He provided lots of evidence to support the theory of evolution by natural selection. 

Name 4 types of evolutionary evidence

• Fossil evidence

• Molecular evidence 

• DNA evidence

• Embryonic evidence

Describe how DNA can be used to prove evolution by natural selection

• The theory of evolution suggests that all organisms have evolved from shared common ancestors

• Evolution is caused by gradual changes in the base sequence of an organism's DNA

• Organisms that diverged away from each other more recently, should have more similar DNA.

Describe how molecular evidence can be used to prove theory of evolution by natural selection

• similarities in other molecules provide evidence

• the sequence of amino acids in proteins can be used. 

• Organisms that diverged away from each other more recently have more similar amino acid sequences, as less time as has passed for changes to occur.

Describe how fossil evidence can be used to prove evolution by natural selection

• Fossils are the remains of organisms preserved in rocks.

• By arranging fossils in chronological order,  gradual changes in organisms can be observed.