C4.1. Populations and communities

Outline a method that could have been used in this study to measure the numbers of sea urchins per 0.25 m².

Outline a method that could have been used in this study to measure the numbers of sea urchins per 0.25 m².

Explain the technique used to estimate the population size of a named species of organism that is able to move.

The garden snail, Helix aspersa, is a herbivore.

[Source: Sinan Önder /https://www.pexels.com/photo/animal-close-up-crawling-garden-243128/]

Explain how the population of snails in an ecosystem could be estimated by capture-mark-release-recapture, identifying the limitations in the method.

Explain how the population of fish in a pond could be estimated using the capture-mark-release-recapture method.

Explain the technique used to estimate the population size of a named species of organism that is able to move.

The garden snail, Helix aspersa, is a herbivore.

[Source: Sinan Önder /https://www.pexels.com/photo/animal-close-up-crawling-garden-243128/]

Explain how the population of snails in an ecosystem could be estimated by capture-mark-release-recapture, identifying the limitations in the method.

Explain how the population of fish in a pond could be estimated using the capture-mark-release-recapture method.

Black walnut (Juglans nigra) secretes the chemical juglone into the soil surrounding its roots. Juglone inhibits cell respiration in other species of plants. What does this example illustrate?

A.  Mutualism

B.  Intraspecific competition

C.  Allelopathy

D.  Parasitism

Black walnut (Juglans nigra) secretes the chemical juglone into the soil surrounding its roots. Juglone inhibits cell respiration in other species of plants. What does this example illustrate?

A.  Mutualism

B.  Intraspecific competition

C.  Allelopathy

D.  Parasitism

Black walnut (Juglans nigra) secretes the chemical juglone into the soil surrounding its roots. Juglone inhibits cell respiration in other species of plants. What does this example illustrate?

A.  Mutualism

B.  Intraspecific competition

C.  Allelopathy

D.  Parasitism

Black walnut (Juglans nigra) secretes the chemical juglone into the soil surrounding its roots. Juglone inhibits cell respiration in other species of plants. What does this example illustrate?

A.  Mutualism

B.  Intraspecific competition

C.  Allelopathy

D.  Parasitism

Explain the factors that can contribute to the exponential growth phase in a sigmoid population curve.

Explain the factors that can contribute to the exponential growth phase in a sigmoid population curve.

Explain the factors that can contribute to the exponential growth phase in a sigmoid population curve.

Explain the factors that can contribute to the exponential growth phase in a sigmoid population curve.

A hummingbird is shown visiting a large flower.

[Source: Nussbaumer, R./Naturepl.com, n.d. Black chinned hummingbird (Archilochus alexandri). Available at:
https://www.naturepl.com/stock-photo/black-chinned-hummingbird-archilochus-alexandri-male-feeding-at-sageflower/search/detail-0_01140572.html.]

What makes this a mutualistic relationship?

A.  The bird feeds on nectar and transfers pollen to the stamen of a flower of the same species.

B.  The bird obtains nutrients and the plant is assisted with pollination for sexual reproduction.

C.  The bird requires pollen as a protein source and, while obtaining this, disperses seeds for the plant.

D.  The bird transfers pollen to the stigma of flowers of a different species while feeding.

Black walnut (Juglans nigra) secretes the chemical juglone into the soil surrounding its roots. Juglone inhibits cell respiration in other species of plants. What does this example illustrate?

A.  Mutualism

B.  Intraspecific competition

C.  Allelopathy

D.  Parasitism

Black walnut (Juglans nigra) secretes the chemical juglone into the soil surrounding its roots. Juglone inhibits cell respiration in other species of plants. What does this example illustrate?

A.  Mutualism

B.  Intraspecific competition

C.  Allelopathy

D.  Parasitism

Black walnut (Juglans nigra) secretes the chemical juglone into the soil surrounding its roots. Juglone inhibits cell respiration in other species of plants. What does this example illustrate?

A.  Mutualism

B.  Intraspecific competition

C.  Allelopathy

D.  Parasitism

A hummingbird is shown visiting a large flower.

[Source: Nussbaumer, R./Naturepl.com, n.d. Black chinned hummingbird (Archilochus alexandri). Available at:
https://www.naturepl.com/stock-photo/black-chinned-hummingbird-archilochus-alexandri-male-feeding-at-sageflower/search/detail-0_01140572.html.]

What makes this a mutualistic relationship?

A.  The bird feeds on nectar and transfers pollen to the stamen of a flower of the same species.

B.  The bird obtains nutrients and the plant is assisted with pollination for sexual reproduction.

C.  The bird requires pollen as a protein source and, while obtaining this, disperses seeds for the plant.

D.  The bird transfers pollen to the stigma of flowers of a different species while feeding.

Black walnut (Juglans nigra) secretes the chemical juglone into the soil surrounding its roots. Juglone inhibits cell respiration in other species of plants. What does this example illustrate?

A.  Mutualism

B.  Intraspecific competition

C.  Allelopathy

D.  Parasitism

A hummingbird is shown visiting a large flower.

[Source: Nussbaumer, R./Naturepl.com, n.d. Black chinned hummingbird (Archilochus alexandri). Available at:
https://www.naturepl.com/stock-photo/black-chinned-hummingbird-archilochus-alexandri-male-feeding-at-sageflower/search/detail-0_01140572.html.]

What makes this a mutualistic relationship?

A.  The bird feeds on nectar and transfers pollen to the stamen of a flower of the same species.

B.  The bird obtains nutrients and the plant is assisted with pollination for sexual reproduction.

C.  The bird requires pollen as a protein source and, while obtaining this, disperses seeds for the plant.

D.  The bird transfers pollen to the stigma of flowers of a different species while feeding.

Black walnut (Juglans nigra) secretes the chemical juglone into the soil surrounding its roots. Juglone inhibits cell respiration in other species of plants. What does this example illustrate?

A.  Mutualism

B.  Intraspecific competition

C.  Allelopathy

D.  Parasitism

Black walnut (Juglans nigra) secretes the chemical juglone into the soil surrounding its roots. Juglone inhibits cell respiration in other species of plants. What does this example illustrate?

A.  Mutualism

B.  Intraspecific competition

C.  Allelopathy

D.  Parasitism

Black walnut (Juglans nigra) secretes the chemical juglone into the soil surrounding its roots. Juglone inhibits cell respiration in other species of plants. What does this example illustrate?

A.  Mutualism

B.  Intraspecific competition

C.  Allelopathy

D.  Parasitism

Black walnut (Juglans nigra) secretes the chemical juglone into the soil surrounding its roots. Juglone inhibits cell respiration in other species of plants. What does this example illustrate?

A.  Mutualism

B.  Intraspecific competition

C.  Allelopathy

D.  Parasitism

Black walnut (Juglans nigra) secretes the chemical juglone into the soil surrounding its roots. Juglone inhibits cell respiration in other species of plants. What does this example illustrate?

A.  Mutualism

B.  Intraspecific competition

C.  Allelopathy

D.  Parasitism

Black walnut (Juglans nigra) secretes the chemical juglone into the soil surrounding its roots. Juglone inhibits cell respiration in other species of plants. What does this example illustrate?

A.  Mutualism

B.  Intraspecific competition

C.  Allelopathy

D.  Parasitism

A hummingbird is shown visiting a large flower.

[Source: Nussbaumer, R./Naturepl.com, n.d. Black chinned hummingbird (Archilochus alexandri). Available at:
https://www.naturepl.com/stock-photo/black-chinned-hummingbird-archilochus-alexandri-male-feeding-at-sageflower/search/detail-0_01140572.html.]

What makes this a mutualistic relationship?

A.  The bird feeds on nectar and transfers pollen to the stamen of a flower of the same species.

B.  The bird obtains nutrients and the plant is assisted with pollination for sexual reproduction.

C.  The bird requires pollen as a protein source and, while obtaining this, disperses seeds for the plant.

D.  The bird transfers pollen to the stigma of flowers of a different species while feeding.

Black walnut (Juglans nigra) secretes the chemical juglone into the soil surrounding its roots. Juglone inhibits cell respiration in other species of plants. What does this example illustrate?

A.  Mutualism

B.  Intraspecific competition

C.  Allelopathy

D.  Parasitism

Black walnut (Juglans nigra) secretes the chemical juglone into the soil surrounding its roots. Juglone inhibits cell respiration in other species of plants. What does this example illustrate?

A.  Mutualism

B.  Intraspecific competition

C.  Allelopathy

D.  Parasitism

E. modestus is an invasive barnacle while the others are native species. Analyse the data to show how it supports this statement.

Explain what is meant by competitive exclusion, with respect to a named example of an invasive species.

E. modestus is an invasive barnacle while the others are native species. Analyse the data to show how it supports this statement.

Explain what is meant by competitive exclusion, with respect to a named example of an invasive species.

To calculate chi-squared, expected values must first be calculated. Assuming that there is no association between the two species, calculate the expected number of quadrats in which both species would be present, showing your working.

State the number of degrees of freedom for this test to determine the critical value of chi-squared.

When the data in the table were used to calculate chi-squared, the calculated value was 0.056. The critical value is 3.84. Explain the conclusion that can be drawn from the calculated and critical values for chi-squared.

To calculate chi-squared, expected values must first be calculated. Assuming that there is no association between the two species, calculate the expected number of quadrats in which both species would be present, showing your working.

State the number of degrees of freedom for this test to determine the critical value of chi-squared.

When the data in the table were used to calculate chi-squared, the calculated value was 0.056. The critical value is 3.84. Explain the conclusion that can be drawn from the calculated and critical values for chi-squared.

To calculate chi-squared, expected values must first be calculated. Assuming that there is no association between the two species, calculate the expected number of quadrats in which both species would be present, showing your working.

State the number of degrees of freedom for this test to determine the critical value of chi-squared.

When the data in the table were used to calculate chi-squared, the calculated value was 0.056. The critical value is 3.84. Explain the conclusion that can be drawn from the calculated and critical values for chi-squared.