Question: What animal has the most generations and evolutions?

Hannah Cornish answered on 15 Jan 2019:

Hi Indy,

I had a go at answering your question, but I think the website crashed and lost it, so here goes again!

I would say that because all species share a common ancestor they have all been evolving for the same amount of time. Some species have changed more in how they look and what they do, but it is impossible to say which has changed the most.

Species evolve at different speeds and that change is often very gradual. It can be very difficult to say where one species ends and another one begins, and most species in the past have not left behind any fossils for us to study. This means we can’t say how many species an animal may have ‘evolved through’ in the past.

Generations are easier to measure because a generation is the length of time it takes for an animal to grow up and have babies of its own. Species which live for a long time like humans or elephants have long generations of 20-30 years, and species that live short lives like fruit flies or aphids have short generations of a week or two. The animal species that has had the most generations is probably a fast-reproducing invertebrate, perhaps a nematode worm, which can have a generation length of 3-4 days.