The images show two organisms from the genus Canis.
Grey wolves, Canis lupus, are wild animals native to Eurasia and North America.
Domestic dogs, Canis familiaris, descended from wolves and became domesticated over many years.
A wolfdog is a hybrid produced when a domesticated dog (Canis familiaris) breeds with a wolf (Canis lupus). Genetically, dogs and wolves are very similar and the resulting offspring are fertile. Wolfdog hybrids are rare as natural habitats and territorial behaviours isolate wolves from domestic dogs.
Using the information provided, discuss the validity of the claim that wolves and dogs are the same species.
Spirulina (Athrospira platensis) is a blue-green alga that is consumed for its nutritional benefits, which are considered to be good for oral health, eye health and maintaining healthy blood pressure, amongst other benefits.
The graph shows the results from an investigation into the optimum growing conditions for Spirulina.
Spirulina was grown in a glucose medium and exposed to different intensities of light. The same method was carried out with an autotrophic species of alga.
Explain how the results show that Spirulina is a mixotrophic organism.
Another species of alga, Cephaleurosvirescens, has been identified as a plant pathogen living on the leaves and fruit of guava plants in Hawaii. C. viscerens is non-photosynthetic and has been shown to cause a disease known as leaf and fruit spots.
Identify, with a reason, the mode of nutrition that is represented by C. viscerens.
Many large marine ecosystems across the world's oceans boast high productivity and biodiversity. As a result, they contribute substantially to the global economy through practices such as fishing.
The map below shows 66 large marine ecosystems, which are identified as being key areas of conservational interest, due to the risks associated with their proximity to developed coastlines and the impact this may have on the biodiversity of these ecosystems.
Suggest four abiotic factors that may impact communities living within large marine ecosystems.
A basic food web for a large marine ecosystem can be seen below.
Nutrient-rich sewage from coastal settlements results in rapid growth of algae (algal blooms), which leads to a reduction in light intensity on the ocean floor.
Suggest the general effects this may have on a community in a marine ecosystem.
Since 2013, numbers of starfish in the large marine ecosystems have been seen to dramatically reduce by up to 80% in some regions.
Starfish act as detritivores in the marine ecosystems, feeding on dead and decaying organic matter, as well as preying on organisms such as mussels and limpets.
Some scientists have suggested that a decline in starfish numbers may have a positive impact on the marine ecosystem.
One mark is available for clarity of communication in this question.
a)
Outline how scientists may simulate a naturally occurring ecosystem to establish how the sustainability of that ecosystem may be influenced by global warming.
