Read the passage about wood ticks and tularemia below.
The Rocky Mountain wood tick (Dermacentor andersoni) is a parasitic arachnid that transmits the bacterium Francisella tularensis, the causative agent of tularemia. This zoonotic disease affects various wild mammals, particularly rodents and lagomorphs.
Throughout their multi-stage life cycle, these ticks feed on a variety of hosts. Larval and nymphal ticks primarily feed on meadow voles (which consume seeds and herbivorous insect larvae), whereas adult ticks commonly feed on wild rabbits (which are strictly herbivorous, consuming grasses and clover). If a pregnant mammal is infected, the bacteria can sometimes cross into the fetal circulation, potentially causing miscarriage or congenital infection.
Conservation biologists are investigating targeted vaccination programs for wild animal reservoirs alongside habitat management strategies to regulate tick populations.
Use this information and your biological knowledge to answer the following questions.
The pathogen that causes tularemia is a bacterium. State two cellular structures that are found in all bacteria.
Name the organ that pathogens must cross to get from the mother's blood into the blood of the developing fetus.
Explain how vaccinating an animal against the tularemia bacterium protects it from developing the disease if it is subsequently bitten by an infected tick.
Explain why these ticks can be described as both secondary consumers and tertiary consumers in this grassland food web.
20 exam-style questions on Edexcel IGCSE Biology Feeding relationships. Each one has a worked solution and a mark scheme showing where the marks go.