Genetic Diversity
What is genetic diversity?
The variety of genotypes within a species or population.
Name the three types of adaptations.
Structural, physiological and behavioural.
What type of symbiotic relationship benefits both organisms?
Mutualism (+/+).
What is the name given to an organism that produces its own organic molecules, usually through photosynthesis?
Producer (autotroph).
What is a keystone species?
A species that has a disproportionately large effect on the structure and functioning of its ecosystem.
What is the process called when individuals with advantageous inherited characteristics are more likely to survive and reproduce?
Natural selection.
A bilby's large ears contain blood vessels close to the skin, allowing heat to escape. What type of adaptation is this?
Structural adaptation.
A remora attaches to a shark and eats leftover food. The shark is unaffected. Identify the relationship.
Commensalism (+/0).
In the food chain grass → grasshopper → frog → snake, what trophic level does the frog occupy?
Third trophic level (secondary consumer).
Bilbies dig burrows that loosen soil and provide shelter for other animals. What ecological role does this demonstrate?
Ecosystem engineer.
Why is a population with low genetic diversity more vulnerable to extinction?
Individuals are more genetically similar, so fewer may possess characteristics that allow them to survive environmental changes.
Spinifex hopping mice produce highly concentrated urine. Identify the adaptation type and explain its survival benefit.
Physiological. It reduces water loss, helping the animal survive in dry environments.
A tapeworm lives inside a cow's intestine, absorbing nutrients. Identify the relationship and explain its effects on both organisms.
arasitism (+/−). The tapeworm benefits by obtaining nutrients, while the cow is harmed through nutrient loss.
Why do food webs provide a more realistic representation of feeding relationships than food chains?
They show multiple interconnected feeding relationships, rather than a single pathway of energy transfer.
Explain how dingoes, as apex predators, help maintain ecosystem balance.
Dingoes regulate prey populations, reducing excessive grazing pressure and helping maintain vegetation and biodiversity.
A disease spreads through two populations of the same species. Population A has high genetic diversity, while Population B has low genetic diversity. Which population is more likely to survive? Explain.
Population A. Greater genetic diversity increases the likelihood that some individuals possess resistance to the disease and survive to reproduce.
A red kangaroo rests in the shade during the hottest part of the day and becomes active at dusk. Identify the adaptation type and explain two survival advantages.
Behavioural. It reduces exposure to extreme heat and helps conserve water by reducing heat-related water loss.
A large tree blocks sunlight from reaching smaller plants below it. The smaller plants grow poorly, while the tree is unaffected. Identify and justify the relationship.
Amensalism (0/−). The smaller plants are harmed by reduced light availability, while the larger tree is unaffected.
A producer contains 10,000 kJ of energy. Using the 10% energy transfer rule, how much energy would be available to a tertiary consumer?
10 kJ.
A population of great white sharks declines significantly. Predict how this could affect the populations of their prey and other organisms in the food web.
Prey populations, such as seals, may increase due to reduced predation. This could increase predation pressure on smaller organisms, disrupting food web relationships.
A population experiences a prolonged drought. Explain how natural selection could change the frequency of drought-tolerant characteristics over several generations.
Individuals with inherited drought-tolerant characteristics are more likely to survive and reproduce, passing these characteristics to offspring. Over generations, the frequency of these characteristics increases.
A thorny devil has spiny skin, channels between its scales that collect water, and shelters from extreme daytime heat. Identify two different adaptation types and explain how each improves survival.
Structural: spines deter predators or skin channels collect water. Behavioural: sheltering reduces exposure to extreme temperatures.
Dingoes and foxes both hunt rabbits in the same ecosystem. Identify the type of competition occurring and explain why both species may be negatively affected.
Interspecific competition. Both species compete for the same limited food resource, reducing food availability for each species.
In a grassland ecosystem, snakes feed on frogs, frogs feed on grasshoppers, and grasshoppers feed on grass. Predict the effects on grasshopper and grass populations if the snake population decreases.
Frogs may increase due to reduced predation. More frogs consume more grasshoppers, causing grasshopper numbers to decline. Reduced herbivory may allow grass populations to increase.
African elephants uproot trees, trample vegetation and disperse seeds through their dung. Explain why they are ecosystem engineers and describe two ways their activities can increase biodiversity.
Elephants physically modify habitats. Opening dense vegetation allows smaller plants to grow, while seed dispersal supports plant reproduction and regeneration in new areas.