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BIOLOGY, M2 EQ-Bank 4

Explain how colonial organisms represent an intermediate stage between unicellular and multicellular organisms.

In your answer, include an example that looks at the basic structure of a colonial organism and how it compares to both unicellular and multicellular organisms.   (3 marks)

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  • Colonial organisms represent an intermediate stage between unicellular and multicellular organisms in several ways.
  • The basic structure of a colony consists of many genetically identical cells living together, as seen in sponges where individual cells form a loose association.
  • In terms of cell specialisation, colonial organisms show more diversity than unicellular organisms but less than true multicellular organisms.
  • For example, sponges have some specialised cells for feeding and water flow, but most cells remain relatively undifferentiated.
  • Regarding cooperation, colonial organisms demonstrate more cell interaction than unicellular life forms, with cells in a sponge colony working together to filter water and share nutrients, but they lack the complex, interdependent organ systems found in multicellular organisms.
Show Worked Solution
  • Colonial organisms represent an intermediate stage between unicellular and multicellular organisms in several ways.
  • The basic structure of a colony consists of many genetically identical cells living together, as seen in sponges where individual cells form a loose association.
  • In terms of cell specialisation, colonial organisms show more diversity than unicellular organisms but less than true multicellular organisms.
  • For example, sponges have some specialised cells for feeding and water flow, but most cells remain relatively undifferentiated.
  • Regarding cooperation, colonial organisms demonstrate more cell interaction than unicellular life forms, with cells in a sponge colony working together to filter water and share nutrients, but they lack the complex, interdependent organ systems found in multicellular organisms.

BIOLOGY, M2 EQ-Bank 3

Coral polyps form colonies that can grow into large reef structures.

Explain how coral colonies demonstrate characteristics of colonial organisms.   (3 marks)

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  • Coral colonies demonstrate key characteristics of colonial organisms by showing both unicellular and multicellular characteristics in their structure and behaviour.
  • Each individual coral polyp in the colony is capable of surviving on its own, possessing all the necessary structures for feeding, reproduction, and basic life functions, which is a characteristic of unicellular organisms.
  • However, these polyps also cooperate by sharing resources and forming a collective skeleton, showing a level of integration more characteristic of multicellular organisms.
  • Despite this cooperation, coral polyps generally lack the high degree of specialisation seen in true multicellular organisms, maintaining a relatively uniform structure and function across the colony.
Show Worked Solution
  • Coral colonies demonstrate key characteristics of colonial organisms by showing both unicellular and multicellular characteristics in their structure and behaviour.
  • Each individual coral polyp in the colony is capable of surviving on its own, possessing all the necessary structures for feeding, reproduction, and basic life functions, which is a characteristic of unicellular organisms.
  • However, these polyps also cooperate by sharing resources and forming a collective skeleton, showing a level of integration more characteristic of multicellular organisms.
  • Despite this cooperation, coral polyps generally lack the high degree of specialisation seen in true multicellular organisms, maintaining a relatively uniform structure and function across the colony.

BIOLOGY, M2 EQ-Bank 5 MC

Consider the following statements about colonial organisms:

\(\text{I.}\)   They consist of genetically identical cells.  
\(\text{II.}\)   Each cell in the colony can perform all life functions independently.  
\(\text{III.}\)   They show a higher degree of cell specialization compared to multicellular organisms.  
\(\text{IV.}\)   They represent an evolutionary step between unicellular and multicellular organisms.  

 
Which combination of statements correctly describes colonial organisms?

  1. \(\text{I}\) and \(\text{II}\) only
  2. \(\text{I}\), \(\text{II}\) and \(\text{IV}\) only
  3. \(\text{II}\) and \(\text{III}\) only
  4. \(\text{I}\), \(\text{II}\) and \(\text{III}\) only
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\(B\)

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Consider each statement:

  • \(\text{I.}\) Correct. Colonial organisms do consist of genetically identical cells, as they typically arise from the division of a single cell.
  • \(\text{II.}\) Correct. In most colonial organisms, each cell can perform all life functions independently, although they may benefit from living in close proximity to other cells.
  • \(\text{III.}\) Incorrect. Colonial organisms generally show less cell specialization than multicellular organisms, not more.
  • \(\text{IV.}\) Correct. Colonial organisms are often considered an evolutionary intermediate step between unicellular and multicellular organisms.

\(\Rightarrow B\)

BIOLOGY, M2 EQ-Bank 1 MC

Which of the following best distinguishes a unicellular organism from a colonial organism?

  1. A unicellular organism is made up of multiple cells, while a colonial organism is a single cell.
  2. A unicellular organism can survive independently, while a colonial organism involves many specialised cells that must live as a group to survive.
  3. Unicellular organisms rely on other cells to perform essential functions, while colonial organisms do not.
  4. Unicellular organisms consist of one cell that performs all life functions, while colonial organisms are groups of identical cells that function together but can survive independently.
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\(D\)

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  • In unicellular organisms, a single cell carries out all necessary life processes.
  • Colonial organisms consist of individual cells that are physically connected or grouped, but each cell can perform essential functions independently, allowing survival even if separated from the colony.

\(\Rightarrow D\)

BIOLOGY, M2 EQ-Bank 21

Describe two key differences between colonial and multicellular organisms.   (2 marks)

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  • Colonial organisms do not exhibit specialisation. Each cell in the colony is the same but they are connected in such a way to enhance processes such as food gathering and production.
  • Multicellular organisms do consist of specialised cells, each of which will carry out one specific function which will benefit the whole organism.
Show Worked Solution
  • Colonial organisms do not exhibit specialisation. Each cell in the colony is the same but they are connected in such a way to enhance processes such as food gathering and production.
  • Multicellular organisms do consist of specialised cells, each of which will carry out one specific function which will benefit the whole organism.