Homologous VS Analogous

Homologous VS Analogous

Evolution Quiz 1 Intervention

Take a look at the pictures.

Which species do you think are more closely related?

The prawn and woodlice?

Or dolphins and sharks?

Open Ended

Which species did you think are more closely related?

Why?

Sharks and Dolphins are not closely related.

• So, why do they look so much alike?

Poll

Why do you think sharks and dolphins look so much alike?

• They have a recent common ancestor

• They live in similar environments

• They are both fish

Convergence (Convergent Evolution)

• Two species are NOT closely related - but have similar features because of having similar environmental pressures.

• We call these traits ANALOGOUS

Analogous Traits

The shape of these organisms is due to similar environment - NOT a recent common ancestor.

Multiple Choice

What is the likely cause of analogous traits?

• Two species share a common ancestor

• Two species face similar environmental pressures

• A remnant of a trait that no longer serves a function

Open Ended

What is the difference between a VESTIGIAL trait and a HOMOLOGOUS trait?

Some traits are retained by species, but no longer function or serve a purpose for that species. These are called VESTIGIAL traits. Vestigial traits provide evidence that organisms are closely related.