Evolution with Anatomy?

Question

how does anatomy show evidence of evolution? give example, like Darwin's finches with their evolving beaks... thanks

Answer 1

OK ... evidence of evolution in anatomy. (Forgetting evidence from fossil, genetic, molecular, biogeography, etc.)

There are four main categories of anatomical evidence: vestigial structures, homologous structures, embryological structures, and atavisms.

1. Vestigial structures are features that are useless or nearly useless in one species, and are only explainable as remnants from an ancestral species. The evidence is that this feature is still useful in other species that descended from the same ancestor. Examples in humans are the appendix, wisdom teeth, the muscles that let you wiggle your ears (useless feature in humans, but a remnant of the muscles used by other animals for positioning the ears towards sound), the plantaris muscle (a thin useless muscle in the human calf that is used for grasping in other primates); your big toe (it's not the toe itself, but the *size*, bone structure, muscles, nerves, etc. of the big toe reveal that it is structurally equivalent to the thumb ... i.e. it was once used for grasping); the micro-muscles that give you goosebumps (used for fluffing up the fur in animals in times of cold or stress).

Examples in non-humans are even more numerous ... but I'll just mention a few: hip and leg bones in whales; leg buds in snakes, useless eyes in blind fish and other organisms; hollow bones in penguins (a remnant of their flying ancestors); wings on flightless birds like ostriches and emus; flowers in dandelions (useless as dandelions reproduce asexually, so flowers are remnants of ancestors that needed to attract insects); etc.

2. Homologous structures are a feature in common between two organisms that has a very different function in both. This is evidence of evolution from a common ancestor that had a certain structure, where the structure takes on radically different purposes in different descendants. Examples are the arms of humans and the wings of bats, or the bone structure of the mammal inner ear, is homologous to the bone structure of the reptilian hinged jaw.

3. Embryological evidence Things like gill folds and a tail in the human embryo, leg buds in dolphins and whales, etc.

4. Atavisms. These are rare, but repeatedly reported "birth defects" on a modern animal considered to be a throwback to an ancestor. I.e., these are evidence that the genes for certain ancestral features are still carried in the genotype, and occasionally expressed. Examples that are webbed fingers, babies born with tails, whales and dolphins with rear legs, extra toes on horses, etc.

Answer 2

Darwin's Finches. Sorry!!!

Galapagos tortoises, and those on Aldabra.
Hawaiian birds (also finches I think)
Flightless birds on islands.

Answer 3

God created the eath and everything on it. what darwin is showing is adaptation not evolution