Fig. 1 shows an invasive signal crayfish in a small river in southern England. It is shown beside a native white-clawed crayfish, a burrowed riverbank and e...

Assessment: Geography 9230 | Paper 1 Mock 01 | Written Paper 1 Subject: Geography - 9230

Question 1 Report

9230-p1-living-coral-mooring-05

Fig. 1 shows an invasive signal crayfish in a small river in southern England. It is shown beside a native white-clawed crayfish, a burrowed riverbank and eggs carried under the invasive crayfish. Volunteers have reported that native crayfish are becoming difficult to find. Ecologists are concerned that the invasive species may spread through connected streams and alter the river habitat.

(a) Outline two reasons why an invasive crayfish may reduce the native crayfish population. [2]

Answer Details

(a) Any two: competes with native crayfish for food [1]; competes for shelter/burrows [1]; may eat native eggs or young [1]; may carry disease to which native crayfish have little resistance [1]; burrowing can alter habitat [1].

Download The App On Google Playstore

Everything you need to excel in your exams

Green Bridge CBT Mobile App
Personalized AI Learning Chat Assistant
200,000+ Exam Questions Across IGCSE, JAMB, WAEC & NECO
Over 3,900 Lesson Notes
Offline Support - Learn Anytime, Anywhere
Green Bridge Timetable
Literature Summaries & Potential Questions
Track Your Performance & Progress
In-depth Explanations for Comprehensive Learning