Practise IB Biology HL A3.1 with classification and data questions on domains, kingdoms, shared characteristics and genetic, species and ecosystem biodiversity.
102 questions in this syllabus scope, with question parts counted together.
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The land snail Cepaea nemoralis is very common in North America and in Europe.
The base colour of its shell varies between brown, pink and yellow, and also in its intensity. Some shells are unbanded, but most show one to five bands of different width on top of the shell base colour.
C. nemoralis is a mollusc. Identify two external features that distinguish this snail from an arthropod.
Species are groups of organisms that can potentially interbreed to produce fertile offspring.
Suggest advantages of the system for naming species that scientists use.
More than 8 million different species are alive today but over the course of evolution, more than 4 billion may have existed.
Outline the criteria that should be used to assess whether a group of organisms is a species.
Evolution Canyon is a steep sided rocky valley near Mount Carmel in Israel. There are populations of fruit flies (Drosophila melanogaster) living on the north facing and south facing slopes of the canyon. Fruit flies are sensitive to drought conditions and die if they become desiccated.
Twenty samples of fruit flies were collected from both sides of the canyon. They were subjected to the same conditions of drought stress and the life span (in hours) of the adult flies was measured.
Discuss whether the populations on the two slopes could evolve into two species.
Chromosome numbers vary between species. Which statement refers to humans?
An egg cell has 22 autosomes.
A sperm cell has 23 autosomes.
An egg cell has two X chromosomes.
A zygote has two autosomes.
The karyogram is taken from a primate.
All primates have the same sex determination chromosomes. From which primate is the karyogram?
Human female
Chimpanzee female
Human male
Chimpanzee male
The DNA sequences found in human cell lines of various ABO phenotypes are remarkably similar. The blood group gene that codes for intron 6 of glycosyltransferase consists of a 1062 base pair nucleotide sequence.
The table shows the sequence differences in intron 6 of the major ABO alleles for this gene. The nucleotides that are not shown are identical in the three blood group alleles, while the bolded letters show differences with the blood group A allele sequence.
Calculate the percentage difference in bases between the allele for blood group A and the allele for blood group B for intron 6 of this gene, showing your workings.
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 estimated total number of genes in several organisms.
What can be deduced from the information in this table?
Throughout evolution, the number of genes increases.
The domestic dog is more closely genetically related to the fruit fly than to the human.
The number of genes does not determine evolutionary success.
Humans produce about half as many proteins as rice.
A protein expressed by the gene carotene desaturase (CTP1) was introduced into Golden rice (Oryza sativa) through genetic engineering. Bioinformatics were used to determine if the protein sequence matched any allergenic proteins (proteins that trigger an allergic reaction). The table shows the results from the alignment of the CTP1 protein with proteins from moth, soybean and dust mite that are known to be allergenic.
Genes such as the one coding for CTP1 can be located by searching for open reading frames. Outline how open reading frames are identified.
The gut of a healthy human contains more than 1000 species of bacteria. Some of these species are shown in the cladogram.
Outline a difficulty in applying the biological species concept to bacteria.
Which is a characteristic of the haploid number of eukaryotic chromosomes?
It doubles in mitosis.
It is fixed for each species.
It is an even number for all species.
It is positively correlated with an animal's mass.
The following shows a dichotomous key.
Using the dichotomous key above, identify the genus of bird W and bird Z .
Bird W:
Bird Z:
What is one application of DNA barcoding?
Selective breeding
Preserving an endangered species
Analysing environmental DNA
Sequencing a genome
