Practise IB Biology SL A3.1 with questions on classification, domains, kingdoms, biodiversity and the characteristics used to compare organisms.
Which population group has the greatest variation in height?
Age group
List two anatomical features of humans that are characteristic of primates.
1.
2.
The image represents the structure of the enzyme Rubisco from common pea (Pisum sativum).
State the genus of the plant where this Rubisco is found.
Discuss the definition of the term species.
The graph shows the song duration of birds from the genus Phylloscopus sampled from west to east throughout Northern Europe and Northern Asia.
What concept do these data illustrate?
Gradual divergence
Adaptive radiation
Interbreeding populations
Punctuated equilibrium
The western gorilla (Gorilla gorilla) is the largest primate. Sex determination in gorillas is the same as in humans. The image shows a karyogram of a gorilla.
State the chromosome number in this gorilla.
The western gorilla (Gorilla gorilla) is the largest primate. Sex determination in gorillas is the same as in humans. The image shows a karyogram of a gorilla.
Acrocentric chromosomes have a centromere near one end of the chromosome.
Draw a circle around the row on the karyogram that contains all acrocentric chromosomes.
Describe how a karyogram is constructed.
Cultivated rice, Oryza sativa, is one of the most important human foods. The two main sub-species of cultivated rice are O. sativa indica and O. sativa japonica. O. rufipogon is a wild species from which they probably evolved.
To investigate whether the sub-species of cultivated rice evolved independently from the wild species, scientists analysed their chromosomes to find areas with similar DNA base sequences. Wild species tend to have many different alleles of genes present on each chromosome, but during the development of a crop plant by artificial selection from a wild species, this diversity drops considerably, increasing the base sequence similarity.
The number of different alleles of the genes on a chromosome can be represented by a diversity index. The following graph of part of chromosome 7 shows the diversity index of O. rufipogon and two varieties of cultivated rice, O. sativa indica and O. sativa japonica. The gene PROG1 allows the plant to stand upright, which is typical of cultivated rice. Its position is indicated by the vertical arrow on the graph.
Determine which type of rice has the lowest overall diversity index.
Compare and contrast the trends for O. rufipogon and O. sativa indica.
In another experiment, scientists retrieved genome sequences of the wild rice O. rufipogon taken from a wide range of geographical sites (I, II and III) and those of the two sub-species of O. sativa from gene banks.
The pie charts, presented along with a cladogram, show the proportion of alleles for three genes which confer specific characteristics to O . sativa. Mutations can produce derived alleles that are different from the original ancestral alleles. The control group represents wild rice species other than O. rufipogon.
State the proportion of the ancestral allele for the gene GS3 in the O. rufipogon-III population.
Distinguish between the proportion of ancestral and derived alleles for all three genes in O. sativa indica and O. sativa japonica.
Analysis of the genome of primates reveals many DNA segments that have been duplicated. It is possible to deduce the stage in evolution at which segmental duplications (SDs) occurred by comparing human and other primate genomes. Human-specific SDs occurred after humans and chimpanzees diverged. Human-chimpanzee shared SDs occurred after the common human-chimpanzee ancestor diverged from gorillas and so on. It is possible to estimate the rates at which SDs occurred during evolution using knowledge of when the primates changed. In the chart the bars indicate numbers of shared SDs and the line shows estimates of the rate of SDs per millions of years (Myr).
State the number of SDs that can be found in humans but not in other primates.
State the rate of SDs after the divergence of macaques from the other primates, giving the units.
Outline the trends in the rate of SDs occurring since the separation of orangutans from other primates.
Explain how the number of human-chimpanzee shared SDs can be the lowest despite the rate of SDs per millions of years being the highest.
A few SDs were found in humans and gorillas but not chimpanzees. Suggest how this might have occurred.
The table shows the nuclear DNA content of some plant and animal species.
Using the data provided in the table, discuss whether genome size positively correlates to organism complexity.
A section of mRNA contains the start codon for translation of a polypeptide by the ribosomes.
Describe how bioinformatics can help identify genes within the DNA of an organism.