C4.1: Populations & Communities (Combined SL & HL)

What is a population defined as?

• A group of organisms of the same species living in different areas

• A group of organisms of different species living in different areas

• A group of organisms of the same species living in an area at one time

• A group of organisms of different species living in an area at one time

What is the maximum number of individuals of a species that an ecosystem can support known as?

• Limiting factor

• Exponential growth

• Population density

• Carrying capacity

Which phase of the sigmoid growth curve represents the point at which the population growth starts to level off?

• Decline phase

• Plateau phase

• Exponential phase

• Transition phase

What is the method used to estimate the number of individuals in a population of motile organisms?

• Systematic Sampling

• Random Quadrat Sampling

• Capture-mark-release-recapture

• Frame Quadrat Sampling

What is the strategy where organisms secrete harmful chemicals into the environment to harm competing species?

• Allelopathy

• Predation

• Camouflage

• Antibiotic Secretion

What is the purpose of using a turbidity meter in measuring yeast population size over time?

• To measure the temperature of the growth environment

• To determine the pH level of the nutrient broth

• To assess the color change of the nutrient broth

• To calculate the number of yeast cells present

What is the term used to describe the relationship between organisms of the same species working together to aid survival?

• Parasitism

• Cooperation

• Competition

• Mutualism

What is the main reason for the introduction of invasive species into new ecosystems?

• Climate change

• Genetic mutations

• Human activities

• Natural migration patterns

What is the ideal niche called in a habitat, and what is the term for the niche that a species actually occupies?

• Fundamental niche, Realised niche

• Primary niche, Secondary niche

• Optimal niche, Utilised niche

• Main niche, Secondary niche

How can a chi-squared test be used in biology to determine the association between two species in a habitat?

• By comparing observed and expected values

• By measuring the temperature of the habitat

• By counting the number of predators in the area

• By analyzing the soil composition