Well, to be pedantic, any photon above absolute zero [Kelvin] IS ionizing radiation. [I will pass on any philosophical arguments concerning photons with zero energy as existing or not. Even if such a species of photon exists, we would not be able to detect it].
The more energetic a photon is, the more likely it kick an electron out of it's orbital. Stuff like UV is termed ionising because the 'blue" part of the spectrum is vastly more energetic than the 'red" bits.
Infra-red will cause excitation of atoms, and will emit light, and such light will be visible if hot enough.

But organisms have evolved mechanisms to deal with energetic photons, "ionising" or not. UV does not give you cancer. The imperfect DNA and tissue repair mechanisms, and holes in the immune system defense, give you cancer.
So there is nothing really novel about life dealing with ionizing radiation. Some cosmic rays have always got through our atmosphere, and some organisms are well-adapted to even the nuclear fission in natural nuclear reactors [think Oklo].
So basically, it is a game between ionising radiation "trying" to fuck things up, and body repair mechanisms doing their thing. Constant repairs will reduce telomere length, and so cells will start to churn out enzymes that won't work, heat shock proteins that won't protect, and so on. In short, you age more quickly.
It all boils down to evolutionary strategy in eukaryotes. Sex compromises body maintenance. Because nutrients and energy are diverted from growth and body maintenance to sexual maturation and reproduction. Of course, this varies within and between species.