4.2.2 Classification And Evolution Flashcards
What is the definition of classification?
The organisation of living things into groups according to their similarities
What is the definition of a phylogenetic hierachy?
Organisms are placed into groups based on increasing similarities
What is the order of the phylogenetic hierachy?
Kingdom
Phylum
Class
Order
Family
Genus
Species
What are the three domains?
Archaea, Eubacteria and Eukaryotes
What is meant by ‘phylum’?
All the groups in a phylum have the same body plan e.g. Invertebrates
What is meant by orders?
Smaller groups within different classes e.g. Carnivora in Mammals
What is a genus?
A group of closely related animals e.g. Canis (Canines)
What is the definition of a species?
Where animals can breed successfully to produce fertile offspring
What are the features of a protocista?
- Predominantly unicellular
- A nucleus as well as membrane bound organelles
- Some have chloroplasts
What are the features of Plantae?
- Multicellular
- Have nuclei
- Contain chlorophyll
- Autotrophic feeders
- Store food as starch
What are the features of prokaryotae?
- Unicellular
- No nucleus or membrane bound organelles
- No visible feeding mechanism
What are the features of fungi (kingdom)?
- Unicellular or multicellular
- Nuclei and other membrane bound organelles
- No chloroplasts or chlorophyll
What are the features of archaebacteria?
- Extremophiles
- Different RNA
- Membranes are different
What are eubacteria?
- Found in all environments (‘standard bacteria’)
- Chemically different form archaea
Why do scientists classify organisms?
- To identify species
- To predict characteristics
- To find evolutionary links
What is the difference between fertile and viable offspring?
- Viable means it survives fertile means it can produce offspring itself
What is the definition of phylogeny?
Name given to evolutionary relationships between organisms
What does a node mean on a phylogenic tree?
- Where species evolved apart from a common ancestor
- The closer to the node a species the more closely related they are
What is the definition of a common ancestor?
- Species that all modern day species are descended from
What are the two causes of variation?
- genetics
- environmental
What is discrete variation?
- Variation controlled by only a single gene (or very few)
- Tend to be certain variants
- e.g. blood group
What is continuous variation?
- Whenever there is a range of any value
- Shows as a normal distribution pattern
- Usually controlled by multiple genes and influenced by environment
What are the genetic causes of variation?
Alleles- Dominant and recessive from each parent
Mutations- Change in genetic code
- Meiosis- Mix of different alleles
Sexual reproduction- Inherit genes from both parents
Chance- Chance of each gamete fertilising
What are the environmental causes variation?
- Conditions- e.g. lack of nutrients can effect growth
- Injury/disease can damage tissues
What are the fossil records?
- Fossilised evidence of different points in the evolutionary tree of extinct and living animals
What are the problems with the fossil record?
- Soft bodied organisms may decompose too quickly
- Certain conditions are needed
- May get destroyed by earths movements
- May lie undiscovered
What are the key points in the evolution of the theory of evolution?
Late 1700s came an interest in selective breeding
1798- Human populations always increase more quickly than the food supply
Early 1800’s- That fossils in older rocks are simpler than in newer rocks
George Cuvier produced fossil evidence for essentialism
1809 Lamarck- that species changed over time (a. Couldn’t give time frame and b. Thought changes occurred during life could be passed on)
1859 Darwin and Natural Selection
1900- Mendel and his peas
How does comparative anatomy provide evidence for evolution?
Homology in structure show evolution from a common ancestor then adapted for survival
How does evolutionary embryology provide evidence for evolution?
Embryos are all similar in early stages of fertilisation and some features are often lost.
Indicates all vertebrates developed that way
How does comparative biochemistry provide evidence for evolution?
Able to study similarities and differences in proteins such as DNA to show evolutionary links
What are neutral mutations?
Mutations that occur outside functional regions of DNA
What is the definition of an adaptation?
A characteristic that enhances survival
What is divergent evolution?
Where two species have evolved from a common ancestor
What is convergent evolution?
When two entirely separate species evolve to have the same features based on their surroundings
What is the definition of standard deviation?
A measure of how spread out the data is
What are the characteristics of a normal distribution?
- Mean,mode, median are the same
- Bell shaped distribution
- Symmetrical about the Mean
- Numbers of individuals at extremes are low
What does an rs value of +1 mean?
Perfect positive correlation
What were Darwins observations?
- Offspring are similar to parents
- No two organisms are identical
- Organisms can produce a large number of offspring’s
- Populations remain stable
What were Darwins conclusions?
- Selection pressure- struggle to survive
- Better adapted individuals survive better and pass on their genes
-Over time a number of changes give rise to a new species
What is the definition of selection pressure?
Factors that affects an organisms survival
