Kalasta ihmiseksi osa x

Varhaisten keuhkokalojen, jotka molekyyligenetiikka on jo osoittanut tetrapodien esi-isiksi, siirtyminen maalle ei ollutkaan niin monimutkaista kuin joskus on ajateltu. Morfologisiin muutoksiin riitti muutama avainmuuttuja.

"The results showed that, surprisingly, the transition from simple fish hip to complex weight-bearing hip could be done in a few evolutionary steps.

"Many of the muscles thought to be "new" in tetrapods evolved from muscles already present in lungfish. We also found evidence of a new, more simple path by which skeletal structures would have evolved," Dr Boisvert said.

The researchers found that the sitting bones would have evolved by the extension of the already existing pubis. The connection to the vertebral column could have evolved from an illiac process already present in fish.

"The transition from ocean-dwelling to land-dwelling animals was a major event in the evolution of terrestrial animals, including humans, and an altered hip was an essential enabling step," Dr Boisvert said.

"Our research shows that what initially appeared to be a large change in morphology could be done with relatively few developmental steps."

http://phys.org/news/2013-05-ocean-fishy-hips.html

Kalasta ihmiseksi, kalasta ihmiseksi...Tätähän kreationistit hokevat pilkkaamis tarkoituksessa, mutta nyt tämä todeksi jo tiedetty mantra sai lisää todisteita. Ei se maalle siirtyminen niin mahdotonta ollutkaan.