Classification and Evolution Flashcards
What is the order of the Linnaean classification?
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
What are the 3 domains?
Archea - ancient bacteria and extremophiles
Eukarya - eukaryotes
Eubacteria - real bacteria, unicellular organisms without a nucleus
What are the reasons for classification?
- Identifying species
- Predict characteristics
- Find evolutionary links
What is phylogeny?
The evolutionary links between organisms
What does a phylogenetic tree show?
- Evolutionary relationships
- Evolutionary timeline
- Continuous
What are the 3 types of evidence for evolution?
Palaeontology - Study of fossils
Comparative anatomy - Anatomical differences between organisms (homologous structures)
Comparative biochemistry - DNA bases and amino acid sequences
What does palaeontology show us?
- Simple lifeforms evolve into complex ones
- Animals need plants to survive, as plant fossils were formed before animal ones
- Find how closely related organisms are might be based on similarities or differences in structure
What is the problem with palaeontology?
- Incomplete fossil record as most are discovered by accident
- Tectonic plate movements can break fossils or move them
What does comparative biochemistry show?
- Important molecules are highly conserved (eg cytochrome c is involved in respiration in every living organism)
- Cytochrome c can be compared in different organisms, and closely related organisms have very similar or the same amino acid sequence for it
What does the t test and spearman’s rank show?
t test - Compares mean data to see if there is a significant difference two sets of data
Spearmans rank - Find if there is a positive or negative correlation between two sets of data
What is a null hypothesis?
Any relationship/correlation between two sets of data is only due to chance
When do you reject the null hypothesis, and why?
When the t value is bigger than the critical value, as we are more than 95% confident that there is a significant difference
What is the difference between intraspecific and interspecific variation?
Interspecific - The variation seen between different species
Intraspecific - Differences seen between the same species
What is continuous and discontinuous variation?
Continuous - Numerical data, quantitative and usually represented on a line graph
Discontinuous - Grouped or distinct data, qualitative and represented with bar charts
What are some causes of genetic variation?
- Dominant and recessive alleles
- Mutations (random replication error, mutagens or carcinogens)
- Meiosis in crossing over and independent assortment
- Random fertilisation as any sperm cell can fertilise any egg cell
What are the different types of adaptations?
- Behavioural
- Anatomical - physical features
- Physiological - chemical processes like photosynthesis and digestion
What is divergent evolution and convergent evolution?
Divergent - Two species have evolved from the same common ancestor and have homologous structures
Convergent - Two species share similar adaptations in the same habitat but have different evolutionary origin
What are analogous structures?
Similar appearance and function, but different underlying structure and origin
What are the stages of evolution by natural selection?
- Pre-existing variation - There are individuals within a population that have shown different adaptations, this is due to mutations
- Change in selection pressure - Change in environment that causes some individuals to survive, and some to die, for example a flood. Best adapted individuals can survive and reproduce
- Pass on advantageous and favourable allele - repeated over many generations
- Repeats leading to increased allele frequency
- Overtime, this can lead to speciation
