I’m not a biologist, but even I still can see when some people make strange claims about biology. But maybe not being an expert can help here because I don’t know enough to give a super detailed explanation.
- Nature vs nurture is really complicated. I think to some people nurture has become almost synonymous to “choice” because of the use of this phrase in discussions about child-rearing and personal development, like the debate over whether or not people are “born gay”. But nurture also encompasses stuff in the environment that no one may reasonably have control of, like exposure to certain hormones in the womb.
- This also ties into genetic causes being hard to figure out. Many traits that are associated with a known gene aren’t completely controlled by it – it just may increase or decrease the odds of a person having it, because there are still environmental influences. The other issue is that many traits are influenced by multiple genes. For instance, 33 different parts of the human genome may be related to Alzheimer’s disease.
- Being allergic to something doesn’t mean you are allergic to every molecule in it. This seems to come up a lot in debates on GMOs, when people raise concerns about people having allergies to novel genes. Those concerns are mostly legitimate, but it’s worth pointing out almost any new molecule we encounter could end up being an allergen. (Latex and nickel allergies were probably surprising when they first started showing up in populations.) We could actually test if whatever a new gene expressed could cause an allergic reaction. For instance, this paper says most shellfish allergies seem to be in response to one protein. Or your may know people who are allergic to cow’s milk, but can still eat beef. And it makes sense, because a major piece of evidence supporting evolution is how similar many proteins are across different species – we share a lot proteins with all the other multicellular species on Earth.
- One study doesn’t really prove anything. This applies to all science, but it seems to come up a lot in reactions to reporting about biology and medical studies. One study saying something about a specific effect of eating chocolate or finding a gene correlating to a disease doesn’t mean much. A hallmark of modern science is reproducibility, and so we should generally look at multiple studies before accepting things as “fact”.
- Genetic engineering does not work like LEGO. The TV tropes link explains a lot. And the Analysis page on TV Tropes also explains how this actually works in relatively accessible detail. You won’t get wings by adding bird genes to your genome – even if you got the right Hox genes, you would also need to still ensure the right signals were sent to activate the genes to begin the appropriate limb formation.
- Rates of change matter. When people are concerned over climate change or pollution or other impacts humans have on the environment, it’s not that ecosystems can’t adapt to any change. The issue is that if the environment changes too fast, it can outpace the speed at which organisms can adapt and cause a large number of extinctions.