There is a continuum of species, but they don't exist at the same time. Take a human woman. She holds hands with her mother. Her mother holds hands with her

There is a continuum of species, but they don't exist at the same time. Take a human woman. She holds hands with her mother. Her mother holds hands with her mother, and so on. Take a female chimpanzee. She holds hands with her mother. Her mother holds hands with her mother, and so on. Eventually, these two chains meet the same organism, the last common ancestor of human and chimpanzee, who lived somewhere around 6 million years ago. This (now singular) chain has somewhere around 600,000 individual organisms, where each pair next to each other holding hands are related as mother-daughter (so how could you argue they're different species?), but the endpoints of the chain are modern human and modern chimpanzee. As a side note, categorizing life via the idea of species seemed like a good idea when it was developed, but we now know it's not. There's other (real life) examples that show that the idea of species is just a human invention that humans try to fit onto a reality that's more complicated and doesn't respect human abstractions.