Evolution Flashcards
What is continuous variation?
It has no distinct categories, quantitative data and has no limit value
E.g. (height, weight)
Line graph
Controlled by gene and environment
What is discontinuous variation?
There are distinct categories, usually the data is qualitative
E.g (fingerprints, blood group, tongue rolling)
Bar graph
Controlled by a few genes
Define evolution
The gradual process of genetic change in a population that is inherited over several generations
How are fossils formed
Animals die near sedimentary rocks, dead organisms are buried by new layer of earth and rock, they are preserved in the buried rock layer as the calcium in the bones of the organism has mineralized so they harden.
What are the 2 categories of fossils
Trace fossil and body fossil
Body fossil or trace fossil? The remains of body parts
Body fossil
Give some examples of body and trace fossils
Body = shell, bone, teeth
Trace = footprints, faeces
What is a trace fossil?
Something an organism has left behind
True of false, the deeper the strata (laid down layers of sedimentary rock) the younger the organism is
False
What are the 2 methods to determine age of fossils
Relative dating and absolute dating
Which type of dating is this?, Look at another fossil either younger or older, but we don’t know the exact age
Relative dating
What is absolute dating
We can determine exact age of the fossil (via carbon dating)
What is carbon dating
Radioactive C-14 in the atmosphere turns into radioactive CO2 which plants use to photosynthesise and is incorporated into animals when the plants are eaten. We then measure the decay of the C-14 using its half life as guidelines for the age of the fossil
The older a sample, the less C-14 is detected, true or false
True
What are the 6 evidences of evolution
Fossils, geographical distribution, comparative anatomy, comparative embryology, biochemistry and DNA homology
What is geographical distribution
Closely related organisms are now geographically separated so adapt to new environments, due to natural selection and environmental pressures new species are gradually produced via adaptive radiation
What is homologous structure
A similar structure from different species that perform a different function. The organisms evolve from a common ancestor
What is convergent evolution
Organisms evolve by converging towards a shared function e.g. different structure but similar function
What is analogous structure
Organisms have no common ancestor but the structures are used for similar functions e.g. penguin and dolphin (fins/flippers)
What is divergent evolution
When organisms evolve by diverging away from the original species e.g. same structure different function
What is vestigial structure
Organisms have structures that are useless or have lost their original function e.g. appendix and wisdom teeth
What are the types of evolution
Divergent evolution, convergent evolution, vestigial evolution
What type of evolution is this , evolution out of a certain adaptation
Vestigial evolution
True or false, most vertebrate have different early embryonic development
False
True or false, embryos from different species only start to lose their similarities in the later stages of embryonic development
True
How is biochemistry used to compare organisms
Universal bases of nucleic acids, metabolic pathways of physiological processes (e.g. breathing, digestion) and the universal use of ATP energy
What is DNA homology
Comparing protein sequence and DNA and amino acid sequences between different organisms
What are the 2 main theories of evolution
Lamarckism and Darwinism
Which theory of evolution is this, if the body parts that are always used will grown stronger (and vice versa) and an organism can pass these modifications onto their offspring
Lamarckism (theory of the giraffe necks)
What is Darwinism
Species have evolved from their ancestors via natural selection (those with advantageous characteristics survive and reproduce passing on these favourable genes)
What were Darwin’s observations from the Galapagos islands
Birth rate is greater than needed BUT the population usually remains stable quantitively for a long period, “survival of the fittest”, variation is naturally occurring within a population
What is radiometric age often referred to as
Absolute age
What are the 2 mechanisms of evolution
Microevolution and Macroevolution
Which mechanism of evolution is this, caused by mutations, genetic drift, gene flow, artificial and natural selection?
Microevolution
What are the differences and similarities between allopatric and sympatric speciation
Allopatric and sympatric both involve reproductive isolation but in allopatric the populations are geographically isolated whereas sympatric has pre and post-zygotic isolation
What are causes of macroevolution
allopatric and sympatric speciation (also extinction as species arise via speciation)
How many types of natural selections are there and what are they?
3 types, stabilising selection, diversifying/disruptive selection and directional selection
Which type of selection can have the graph moving either to the left or the right
Directional selection
What industries use artificial selection and why?
For crops, making them resistant to pesticides and for sheep, making them fatter and fluffier for more meat and wool
Which selection does this graph describe, the graph looks the the Petronas twin towers with a shorter CN tower in between
Diversifying/disruptive selection
The weight of new-born babies are an example of which type of selection
Stabilising selection
What are the pre-zygotic isolations
Temporal, behavioural, ecological and mechanical isolation
What are the post zygotic isolations
Hybrid inviability, hybrid infertility and hybrid breakdown
Which type of isolation is this and is it pre or post-zygotic, when organisms don’t mate because of different mating calls
Behavioural isolation, it is pre-zygotic
Which type of isolation is this, when organisms don’t mate because they physically cannot
Mechanical isolation
What is temporal isolation
When organisms cannot mate because of different breeding seasons
What are the different types of mutations that can lead to microevolution
Gene mutations, chromosome mutations and genome mutations
Describe each of the 3 mutations that can cause microevolution
Gene: change to the nucleotide sequence
Chromosome: change to the structure/arrangement of chromosomes
Genome: change to the number of chromosomes
Name the different types of chromosome mutations
Insertion, inversion, deletion, duplication, translocation
What are the different types of gene mutations
Insertion, deletion, substitution
What are aneuploidy and euploidy
They are examples of genome mutations, euploidy is a change in ttl number of chromosomes
What causes a change in gene flow
Migration
Is this high or low gene flow, allele frequency increases, not a lot of migration and genetic variation increases
Low gene flow
Describe high gene flow
Lots of migration and genetic variation decreases
What are the 2 types of genetic drift
Bottleneck and founder
What is genetic drift
Random changes to the allele frequency in the gene pool of a small population by chance
What type of genetic drift is this, a small group of individuals are isolated from the main population, this does not affect the main population
Founder effect
Describe the bottleneck effect
When a population rapidly decreases in size due to natural causes/events whereby the original population is impacted
Explain directional selection (e.g. the peppered moths)
Organisms are forced to adapt or die, the populations variation is heavily reduced as a single phenotype is favoured
What type of natural selection is this, extreme ends of a trait are favoured so population variation is reduced but not massively
Disruptive/diversifying selection
Describe stabilising selection
An average phenotype is favoured so genetic variation of a population is reduced across time
Is antibiotic resistance an example of natural selection
Yes
Is a non-resistant strain of bacteria good or bad and why
Bad as the bacteria are sensitive to the antibiotics so die
How does antibiotic resistance happen
Some bacteria are naturally resistant, all the other strains die so the resistant one grows and passes its drug resistance genes etc. onto other bacteria
What is hybrid inviability
They die before they reach reproductive age/maturity
What type of post-zygotic isolating mechanism is this, they are fertile but their offspring has lower survival rate and less reproductive rate
Hybrid breakdown
