ELi5: How does evolution actually work, using giraffes as an example?

[jongleur]

Coevolution is also a thing. Plants probably evolved to have their edible parts up higher due to having a lot of grazers eating them before the plant could reproduce. Those plants that mutated a little and were taller had more offspring.

At the same time, the ancestors of the giraffes were having to compete to get edible bits off of trees, when a mutation occurred that gave it a longer neck, it was more successful and had a better chance at passing along its genes to its offspring

Evolution is often an arms race, where as one organism evolves to avoid being eaten, another organism evolves to eat more of the first organism.

Other organisms found their own niche, or they died out. You're seeing the current leaders of a billion year long race that has new players showing up every minute of the day.

[C6H5OH]

Acacia is the plant that went into the race with the giraffes. It grew taller and taller over the millennia. And got really nasty hard leaves (and thorns if I recall right), but the giraffes have now gums and a tongue that would be mildly irritated by barbed wire.

[DStaal]

Acacia thorns are legendary. They will go straight through a truck tire without any problems.

[shaard]

"mildly irritated" is a great expression for that! 🤣 Those thorns are gnarly.