Grade 12 IEB Life Science Exam With Complete Solutions 2024

Ecology - correct answer-The study of the interactions of organisms with their physical and biological environments. Population ecology - correct answer-The fluctuations in the size of a population and the factors (physical and social) that regulates these fluctuations. Population size - correct answer-The total number of individuals Natality - correct answer-birth rate Mortality - correct answer-death rate Immigration - correct answer-Individuals moving into a population and staying Emigration - correct answer-Individuals leaving a population and not returning Closed population - correct answer-a population that has no immigration and emigration with other populations Environmental resistance - correct answer-The total number of factors that stop a population from reproducing at its maximum rate. Limiting factors build up this. carrying capacity - correct answer-The population density that the environment can support. The pop fluctuates around the carrying capacity. Limiting factors - correct answer-Help to regulate the growth of a population. Density independent factors - correct answer-Limit growth pop. Results natural factors, not bcuz of no. of organisms. PHYSICAL FACTORS (temp, humidity, rainfall) CATASTROPHIC EVENTS (flood, fire, earthquake) Density dependent factors - correct answer-Greater effect pop density is high. More crowded: COMPETE (resources-food,water,light,oxygen,space,shelter) PREDATORS (more easily found) DISEASE (spread easily) stable population - correct answer-Numbers decrease-size exceeds cc Increase-fall below cc FLUCTUATES Unstable population - correct answer-Pop far exceeds cc Habitat: deteriorating rapidly, low cc, not being able to support pop, decrease, extinct