This depends a lot on how much kinship they feel towards us. We wouldn't bat an eye at killing a bunch of primitive single-celled eukaryotes even though they are technically our ancestors.
Single-celled eukaryotes aren't conscious in any meaningful way as far as we can tell.
We humans do in fact feel a sense of obligation to species with whom we are not close kin, but share with us primitive forms of intelligence and consciousness that we do value, e.g. dolphins and elephants. Some of us humans act to protect these creatures and rectify past injustices done upon them.