Transcript 15.3 Evidence of Evolution

15.3 Evidence of Evolution
 Homologous
features
 Analogous features
 Vestigial structures
Homologous features
 Similar features that
have same structures
but different functions.
They come from the
same structures in the
embryo.
 Indicates that different
species shared a
common ancestor.
 Ex. P.289 fig. 15-7.
Penguin, alligator,
human and bat.
Analogous Features

Features which
have different
structures but similar
functions. Shows no
common ancestor.
Ex. P. 290 wings of
hummingbird and
wings of humming
moth.
Vestigial Structures
Features which serve no
function.
Exs. Tailbone,
appendix, nictitating
membrane.
 These features use to be
useful to an ancestor.
 Whales are probably
descended from a land
animal. Some whales
have vestigial hind legs.
Coevolution
 The change of 2
or more species in
close association
with each other.
*Parasites with their
hosts.
*Predator with prey.
*Tropical bat with its
flower it feeds on
p. 291
Convergent Evolution vs.
Divergent Evolution
A. Convergent
evolution
*Shark and porpoise.
They look similar but
not closely related.
Have analogous fins.
Have same
phenotypes which
means they look the
same.
B. Divergent Evolution
*Dogs. They all are closely
related but look different.
1. Adaptive radiation
*many related species
evolve from a single
ancestor
2. Artificial selection
*Breeding for specific
phenotypes like in dogs.
*Gives a variety of
species
*Speeds up divergent
evolution.