Fig. 7.1 is a photograph of a lionfish (Pterois volitans).
(a) State the genus of the lionfish.
(b) Lionfish are classified as fish. Table 7.1 shows features of organisms. Place ticks (✓) in the boxes to show the correct features of birds, fish and insects.
(c) Lionfish are an example of a foreign species that has been accidentally introduced to many marine habitats. Describe the harmful consequences of introducing a foreign species to a habitat.
(d) Removing introduced species from habitats is one method of conserving endangered species. Describe other methods of conserving endangered species.
▶️ Answer/Explanation
(a) Pterois
Explanation: The scientific name of an organism consists of two parts: the genus name (first) and the species name (second). For the lionfish, Pterois is the genus name and volitans is the species name. The genus name is always capitalized when written.
(b)
Explanation:
- Compound eyes are characteristic of insects, not birds or fish.
- Feathers are unique to birds and are not found in fish or insects.
- Both birds and fish have internal skeletons (endoskeletons), while insects have external skeletons (exoskeletons).
(c) Any three from:
- Disruption to food chains/webs through predation
- Competition for food with native species
- Competition for space/mating sites/habitat
- Introduction of new diseases to native species
- Decreasing biodiversity in the habitat
- Potential extinction or endangerment of native species
Detailed Explanation: When a foreign species like the lionfish is introduced to a new habitat, it often lacks natural predators, allowing its population to grow rapidly. This can lead to overconsumption of native species, disrupting the delicate balance of the ecosystem. The lionfish, for example, is a voracious predator that can decimate populations of smaller fish and crustaceans. Additionally, the new species might compete with native species for resources like food and shelter, potentially outcompeting them. In some cases, the introduced species might bring new diseases to which native species have no immunity. All these factors can lead to a decrease in biodiversity and potentially cause the extinction of native species.
(d) Any three from:
- Monitoring and protecting natural habitats
- Establishing zoos, nature reserves, or wildlife parks
- Implementing species monitoring and protection programs
- Public education about conservation
- Captive breeding programs
- Creating seed banks for plants
- Banning hunting/poaching of endangered species
- Implementing fishing quotas for endangered marine species
Detailed Explanation: Conservation of endangered species requires a multi-faceted approach. Protecting natural habitats is crucial as it preserves the ecosystem the species depends on. Establishing protected areas like nature reserves creates safe spaces where species can thrive without human interference. Captive breeding programs help increase population numbers of critically endangered species, with the goal of eventually reintroducing them to the wild. Education raises public awareness about the importance of conservation and how individuals can help. Legal protections like hunting bans prevent further depletion of endangered populations. Each method plays an important role in the comprehensive effort to preserve biodiversity.
Fig. 2.1 shows part of a strawberry tree.
(a) Complete the sentences, using words from the list, to describe how living things are named. Each word may be used once, more than once or not at all.
binomial, dichotomous, gamete, genus, kingdom, offspring, organism, species
The ……………………………….. system is used to give every species a scientific name. The scientific name for the strawberry tree in Fig. 2.1 is Arbutus unedo. Arbutus is the ………………………………… name and unedo is the ………………………………….name.
(b) Describe what is meant by the term species.
(c) Plant species can be identified using a dichotomous key.
Fig. 2.2 shows the leaves from six plant species, A to F.
Use the key to identify the species shown in Fig. 2.2. Write the letter of each species (A to F) in the correct box in the key.
▶️ Answer/Explanation
(a) The binomial system is used to give every species a scientific name. The scientific name for the strawberry tree is Arbutus unedo. Arbutus is the genus name and unedo is the species name.
Explanation: The binomial system assigns a two-part name (genus + species) to organisms for universal identification.
(b) A species is a group of organisms that can reproduce to produce fertile offspring.
Explanation: Members of a species share genetic compatibility, ensuring viable reproduction.
(c) Identifications using the key:
Laurus nobilis – F (smooth margin, no lobes, not needle-like)
Cydonia oblonga – A (smooth margin, no lobes, not needle-like)
Aesculus hippocastanum – E (lobed margin, pointed lobes)
Fraxinus excelsior – D (lobed margin, rounded lobes)
Ilex aquifolium – C (spiky margin, not needle-like)
Quercus robur – B (lobed margin, rounded lobes)
Explanation: The dichotomous key systematically narrows down options based on leaf characteristics (margin type, lobes, etc.).