Species, Communities, Ecosystems & Energy Flow (DP IB Biology: HL)

In a woodland habitat, blue tits and other small birds feed on various species of caterpillar and beetle, which themselves feed on the leaves of trees and herbaceous plants. 

Which of the following statements accurately describes a population within this example?

Sea cucumbers are heterotrophic marine organisms that feed on dead or waste material from the seafloor and surrounding water.  They pick up and consume food particles using specialised tube feet that surround their mouths, as shown in the diagram below.

Which mode of nutrition and explanation is correct for sea cucumbers?

Which of the following statements about inorganic nutrients are correct? 

1. Living organisms gain all of their inorganic nutrients from the abiotic environment.
2. Inorganic nutrients include simple compounds of carbon, hydrogen, oxygen, and nitrogen.
3. Organisms need inorganic nutrients to build organic molecules.

Why are ecosystems considered to be sustainable?

Which of the following statements is an example of a theory being used to explain a natural phenomenon?

The energy transferred from the sun to the grass in this food chain is 65 000 kJ m^-2 year^-1.

 Approximately how much energy is passed from the shrew to the owl in kJ m^-2 year^-1?

Which of the following statements about quadrat sampling are true? 

1. Sampling must be random to avoid bias.
2. Random samples can be achieved by closing your eyes and throwing a quadrat.
3. Quadrat sampling is only useful for small organisms.

A chi-squared test was carried out to test for association between species A and species B.  The results of the chi-squared test are given below. 

Results of chi-squared test:

Critical values table:

What can be concluded from the chi-squared test for association carried out to test for association between species A and species B?

Which of the following considerations should be taken into account when building a mesocosm to test the impact of a particular environmental variable?

Which pyramid of energy correctly represents the food chain shown?

Algae → caddis fly larvae → small fish → kingfisher

The Ghost Orchid (Epipogium aphyllum) is a rare plant species which lacks leaves or chlorophyll. The plant has formed a symbiotic relationship with a fungus in order to obtain the nutrition it requires. The growth of the fungus is slowed as a result of the relationship.

Which of the following rows correctly describes E.aphyllum?

Which of the following statements about inorganic nutrients are true?

1. Carbon and hydrogen are key components of inorganic ions necessary for cell growth and development
2. Inorganic ions enter the ecosystem through plant roots using energy from ATP
3. Drought leading to dry soils results in a reduced availability of inorganic ions
4. Sustainability of an ecosystems relies on inorganic ions being locked up within the biomass of an organism

The graph shows changes in percentage cover of four plant species on a sand dune ecosystem over 500 years.

Which of the following explanations cannot be supported using the information in this graph.

A water quality investigation was carried out after some cases of heavy metal poisoning were detected in a countryside village with a river running through it. The investigators were trying to establish if poisoning was worse on the north or the south of the river.

The results from a chi-squared test were:

Critical values table:

What conclusions can be drawn from the information above?

Which row of the table correctly identifies an observation of food chains and the theory used to explain that observation?

Which of the following is not true about mesocosms?