Scottish Higher Higher Biology Flashcards

24 sample cards from the Higher Biology deck

Sampled from the end of the deck, so these are different cards from the ones shown on the syllabus page.

1. Classify weeds, pests and diseases as the main competitors/threats to crops.

   Weeds compete with crops for light, water and nutrients. Pests (e.g. insects, nematodes, molluscs) damage crops by feeding on them. Diseases are caused by fungi, bacteria and viruses, often spread by pests, reducing yield.

2. Distinguish annual weeds from perennial weeds and their competitive features.

   Annual weeds have rapid growth, short life cycles and produce large numbers of seeds, often surviving as long-term seed banks. Perennial weeds have storage organs (allowing early-season growth) and reproduce vegetatively, making them persistent competitors.

3. Compare selective and systemic herbicides.

   Selective herbicides kill certain plants (e.g. broad-leaved weeds) without harming the crop (e.g. narrow-leaved cereals). Systemic herbicides are absorbed and transported throughout the plant, killing it entirely including storage organs, useful against perennial weeds.

4. Distinguish contact, systemic and selective pesticides.

   Contact pesticides kill on direct contact with the surface. Systemic pesticides are absorbed and spread through the plant/animal tissues. Selective pesticides target specific organisms. Each refers to how the chemical acts to control pests.

5. What problems are associated with the use of pesticides?

   Pests can evolve resistance; pesticides may be toxic to non-target species and humans; persistent chemicals can bioaccumulate and biomagnify up food chains, harming top predators; and runoff can pollute ecosystems.

6. Define bioaccumulation and biomagnification.

   Bioaccumulation is the build-up of a chemical (e.g. a pesticide) within an individual organism over time. Biomagnification is the increase in concentration of that chemical at successive trophic levels up a food chain, so top predators accumulate the highest concentrations.

7. What is biological control and integrated pest management (IPM)?

   Biological control uses a natural predator, parasite or pathogen to control a pest population. IPM combines biological control, chemical control and cultural methods to manage pests effectively while minimising cost and environmental damage.

8. Give the costs and benefits of intensive (indoor) animal farming.

   Benefits: high productivity, efficient use of food/energy, easy management, lower costs and prices. Costs: poor animal welfare (restricted movement, stress), higher disease risk requiring antibiotics, and ethical concerns; behavioural indicators of poor welfare may appear.

9. List the five categories of behavioural indicators used to assess poor animal welfare.

   Stereotypy (repetitive, purposeless movements), misdirected behaviour (e.g. feather/hair pulling), failure in sexual or parental behaviour, altered levels of activity (very high hysteria or very low apathy), and abnormal/displacement behaviour.

10. What is imprinting and why is it important in animal behaviour?

    Imprinting is a form of learning in which a young animal forms an attachment to the first large moving object it sees (usually the parent) during a sensitive critical period. It is important for following the parent, protection, and later mate recognition.

11. Distinguish habituation from other forms of learning.

    Habituation is a simple form of learning in which an animal stops responding to a repeated stimulus that is neither beneficial nor harmful (e.g. ignoring a harmless sound). This conserves energy by not wasting responses on unimportant stimuli.

12. Define symbiosis, and distinguish mutualism from parasitism.

    Symbiosis is a co-evolved intimate relationship between members of two different species. In mutualism both species benefit. In parasitism the parasite benefits while the host is harmed; parasites are often host-specific and have limited metabolism.

13. What is the difference between an endoparasite and an ectoparasite, and what is a vector?

    Endoparasites live inside the host (e.g. tapeworms), ectoparasites live on the surface (e.g. fleas, ticks). A vector is an organism (often a secondary host) that transmits a parasite from one host to another.

14. Explain social hierarchy and its benefits in social animals.

    A social hierarchy is a rank order within a group, often maintained by ritualistic threat and appeasement (submission) displays. Benefits include reduced energy-wasting aggression and serious injury, increased experienced animals' breeding success, and group stability.

15. What is cooperative hunting and how does it benefit social animals?

    Cooperative hunting is when members of a social group hunt together. It allows larger prey to be caught, increases hunting success, requires less energy per individual, and means subordinate animals may gain more food than hunting alone.

16. Define altruism and kin selection in animal behaviour.

    Altruism is behaviour that harms the donor (e.g. costs energy or risk) but benefits the recipient. Kin selection explains altruism towards relatives: helping relatives, who share genes, increases the donor's inclusive fitness by passing on shared alleles.

17. What are social insects and the roles of the castes in a colony?

    Social insects (e.g. bees, ants, termites) live in colonies with a reproductive caste (queen and males) and a sterile worker caste. Workers cooperate to raise relatives, defend the colony and gather food, increasing the survival of shared genes (kin selection).

18. Define biodiversity and list its three components.

    Biodiversity is the variety of life. Its components are: genetic diversity (variety of alleles within a population/species), species diversity (the number of different species and the relative abundance of each), and ecosystem diversity (variety of different ecosystems in an area).

19. Why is a population with low genetic diversity at greater risk of extinction?

    Low genetic diversity means fewer alleles, so the population is less able to adapt to environmental change (e.g. disease, climate) through natural selection, increasing the risk of extinction. This often follows a population bottleneck or small population size.

20. What is a genetic bottleneck and its consequence for a species?

    A bottleneck occurs when a population is sharply reduced (e.g. by hunting, disease or habitat loss), so the survivors carry only a fraction of the original genetic diversity. The recovered population has low genetic diversity and is vulnerable to further threats.

21. Explain how habitat fragmentation threatens biodiversity.

    Fragmentation breaks a large habitat into smaller isolated patches, reducing population sizes and biodiversity. Increased edge effects degrade habitat quality, and isolation prevents interbreeding between fragments, lowering genetic diversity. Habitat corridors can reconnect fragments.

22. How do introduced (invasive, non-native) species threaten native biodiversity?

    Introduced species may prey on, out-compete (for food/resources), hybridise with, or spread disease/parasites to native species that have no co-evolved defences. Naturalised invasive species spread rapidly and can cause native species decline or extinction.

23. State the relationship represented by the Simpson's diversity index and what high values indicate.

    Simpson's diversity index combines species richness and the relative abundance (evenness) of each species. A community with many species in even proportions has high diversity and is generally more stable; one dominated by a few species has low diversity and lower resilience.

24. What is overexploitation and how does it threaten biodiversity?

    Overexploitation is harvesting organisms (e.g. by overhunting or overfishing) faster than they can reproduce, reducing population sizes below recovery levels. It can drive species towards extinction and reduce both species and genetic diversity in ecosystems.

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