The definitions you provided exclude both egg and sperm from being classified as a living organism. They can not reproduce or replicate themselves.
From the National Institute for Health
In biology, it is generally agreed that organisms that possess the following seven characteristics are animate or living beings and thus possess life: the ability to respire, grow, excrete, reproduce, metabolize, move, and be responsive to the environment
The article as a whole elaborates that even trying to pin down a single definiton of life is a bit of a fool’s errand, much less trying to use such a definition to support arguments about when life starts or stops.
From the Stanford Encyclopedia of Philosophy (which actually is just re-quoting an entirely different article, one of many discussed within)
We propose to define living systems as those that are: (1) composed of bounded micro-environments in thermodynamic equilibrium with their surroundings; (2) capable of transforming energy to maintain their low-entropy states; and (3) able to replicate structurally distinct copies of themselves from an instructional code perpetuated indefinitely through time despite the demise of the individual carrier through which it is transmitted.
From a University of Minnesota Introduction to Biology course
All groups of living organisms share several key characteristics or functions: order, sensitivity or response to stimuli, reproduction, adaptation, growth and development, regulation, homeostasis, and energy processing. When viewed together, these characteristics serve to define life.
In short, there really isn’t any unified definition of life. Comparing different definitions, there’s common themes that emerge, but nothing that supports saying conception is when it starts. If you’re going to use that definition, you can’t support it by saying that “science” defines it that way.
jimbolauski@lemm.ee 3 weeks ago
BeardedBlaze@lemmy.world 3 weeks ago
And you think embryo can reproduce/replicate itself? Lol
jimbolauski@lemm.ee 3 weeks ago
Yes an embryo does replicate. How do you think an embryo goes from one cell to multiple cells?
BeardedBlaze@lemmy.world 3 weeks ago
Thru cell division. Didn’t know you were referring to DNA replication, which was not mentioned anywhere in the articles you replied to.
JakenVeina@lemm.ee 3 weeks ago
Considering those quotes talk about defining “living systems” or “groups of organisms”, as opposed to individual cells (and again, elaborated on even moreso within the full linked articles), I’m gonna have to say “no, they’re not really excluded at all.” Their entire purpose is to meet up and initiate replication. An egg and sperm cell are each one small part of a much larger system of ongoing life. The same can be said for a fertilized egg, an embryo, and so on for most stages of development in a womb.
If you want to insist on a definition that says egg and sperm cells aren’t alive, or aren’t an organism, you’re gonna have a hard time saying that a fertilized egg or an embryo are. They don’t replicate on their own, either, not without a very specific environment and set of stimuli.
Also, sperm cells DO replicate, to an extent. They undergo forms of mitosis and meiosis, during their growth. And an egg cell absolutely replicates. Like any other type of cell replication, it needs certain stimuli to initiate it. I.E. it needs to be fertilized.
jimbolauski@lemm.ee 3 weeks ago
If you want to insist on a definition that says egg and sperm cells aren’t alive, or aren’t an organism, you’re gonna have a hard time saying that a fertilized egg or an embryo are. They don’t replicate on their own, either, not without a very specific environment and set of stimuli.
An embryo goes from a single cell to multiple genetically identical cells, that is replication. Sperm cells do not replicate into more identical sperm cells, eggs do not replicate into more identical eggs.
Also, sperm cells DO replicate, to an extent. They undergo forms of mitosis and meiosis, during their growth. And an egg cell absolutely replicates. Like any other type of cell replication, it needs certain stimuli to initiate it. I.E. it needs to be fertilized.
I would argue that the mitosis process sperm cells undergo splits the cell into two genetically different cells and the genetic difference ia not a mutation so it’s not replication. Egg cells don’t replicate they don’t copy their DNA, they fuse with sperm at which time they become an embryo and start to replicate.
realcaseyrollins@thelemmy.club 3 weeks ago
I guess my thing is those descriptors don’t apply to unfertilized embryos.