Evidence of Evolution

Question 1

Fossil Record

Answer 1

sedimentary rock with fossils provides a Fossil Record by showing all the kinds of species that were alive in the past
- fossils closer to the surface are more similar to species alive today
- fossils are in chronological order so ancestors for a species are below the rock where the later species was found
- because not all organisms are in the fossil record at the same time it reinforces evidence that this
organism evolved from another ie: it is believed fish are oldest vertebrates, this is reinforced by fossil records because fish are found in the deepest layer therefore, amphibians evolved from fish, reptiles
evolved from amphibians ( these changes took millions of years

Question 2

Transitional Fossils

Answer 2

Fossils that show intermediary links between groups of organisms and share characteristics
common to two separate groups
- whales have been linked to terrestrial ancestors
- ancient whales had tiny legs and a tiny pelvis but they lived fully aquatic life so these structures
would have been completely useless therefore they have them because they evolved from their
ancestors that needed them on land

Question 3

vestigial structures

Answer 3

They are reduced version or
non-functional version of a structure that was functional in
the organism’s ancestors
- Dogs have a vestigial toe.
- Pigs’ feet have two developed digits the others are vestigial.
- Horses have one enlarged digit and the others are vestigial.
- Whales have a vestigial pelvis
- Geese have webbed feet but live on land

Question 4

Homologous Structures

Answer 4

Homologous Structures – body parts that are similar in structure but have a different function
- Homologous structures are similar because they were inherited from a common ancestor
- Ex: bone structure, hair

Question 5

Analogous Structure

Answer 5

• structures that share a common function but different internal anatomy
• When organisms have these analogous structures it means they do not share a common ancestor
  but they may have just lived in similar ecological niches
• Ex: wings of butterflies and birds, eyes of lobster and fish