Photosynthesis

[Karrueche]

Hello,

 I did a quiz in cytology this morning and I was asked if photosynthesis can only be performed by plants. And the answer was yes. Although also some unicell organisms can perform photosynthesis for example Euglena. Which is not a plant. How would you think about this answer. 

Thank you in advance

[iNow]

53 minutes ago, Karrueche said:

Hello,

 I did a quiz in cytology this morning and I was asked if photosynthesis can only be performed by plants. And the answer was yes. Although also some unicell organisms can perform photosynthesis for example Euglena. Which is not a plant. How would you think about this answer. 

Thank you in advance

Others here may be able to offer a better answer than me, but my immediate thought is that this depends entirely on word definitions. How did they define photosynthesis and how did they define plant.

Your comment about some unicellular organisms performing photosynthesis correctly drives to the heart of this... it reminds us of the sometimes arbitrary thresholds and distinctions between categories we humans impose on nature (plant vs not plant, animal vs not animal, species1 vs species2, as examples).

Word meanings can be fluid and change a bit depending on the context where they’re being used. In this context, their meaning was probably precisely defined by your teacher in a way that allows for this clear answer to the question.

In the end, that’s the answer to your question (it means what the teacher says it means), even though philosophically these boundaries can be quite fun to tweeze apart and explore in more detail. 

Again, someone better versed in this space than me likely can offer a better answer. Go luck in your studies, and welcome to the community. 

[Dagl1]

41 minutes ago, iNow said:

Others here may be able to offer a better answer than me, but my immediate thought is that this depends entirely on word definitions. How did they define photosynthesis and how did they define plant.

Your comment about some unicellular organisms performing photosynthesis correctly drives to the heart of this... it reminds us of the sometimes arbitrary thresholds and distinctions between categories we humans impose on nature (plant vs not plant, animal vs not animal, species1 vs species2, as examples).

Word meanings can be fluid and change a bit depending on the context where they’re being used. In this context, their meaning was probably precisely defined by your teacher in a way that allows for this clear answer to the question.

In the end, that’s the answer to your question (it means what the teacher says it means), even though philosophically these boundaries can be quite fun to tweeze apart and explore in more detail. 

Again, someone better versed in this space than me likely can offer a better answer. Go luck in your studies, and welcome to the community. 

There are also bacteria which perform photosynthesis, so while I do agree that teachers can sometimes define words differently than how they are used scientifically, this seems to just be wrong; Other organisms, which are not plants, can perform photosynthesis. 

Of course it could be possible that the teacher has defined photosynthesis to be "the thing that plants do" but at that point its just a bit silly (in my opinion).

-Dagl

[dimreepr]

26 minutes ago, Dagl1 said:

There are also bacteria which perform photosynthesis, so while I do agree that teachers can sometimes define words differently than how they are used scientifically, this seems to just be wrong; Other organisms, which are not plants, can perform photosynthesis. 

Of course it could be possible that the teacher has defined photosynthesis to be "the thing that plants do" but at that point its just a bit silly (in my opinion).

-Dagl

IIRC photosynthesis is a specialist job done by organisms that want to cooperate and form a symbiosis (much like coral); at which point the distinction is meaningless.  

[hypervalent_iodine]

Algae and Cyanobacteria use photosynthesis, and they are very much not plants. Unless there is some other context missing it seems that the teacher / answer key is incorrect. 

 

6 minutes ago, dimreepr said:

IIRC photosynthesis is a specialist job done by organisms that want to cooperate and form a symbiosis (much like coral); at which point the distinction is meaningless.  

 

Could you clarify what you mean here? 

[dimreepr]

5 minutes ago, hypervalent_iodine said:

Could you clarify what you mean here? 

Lichen, I'm guessing I'm probably wrong here, but when two becomes one, we need a new word...

[CharonY]

2 hours ago, dimreepr said:

Lichen, I'm guessing I'm probably wrong here, but when two becomes one, we need a new word...

Not sure how that changes anything. Symbiotic relationship or not, it does not really change the taxonomy of the partners involved. I.e. there is still sufficient separation as opposed to, say plastids and mitochondria.

With regard to OP under most definitions plants would not be the exclusive group of photosynthetic organisms. One rather obvious question to ask is where did the photosynthetic organelles in plants come from.