Transcript Change over Time

Change over Time
Adaptation
 a characteristic that helps an
organism survive in its
environment
 Two types of adaptations

Structural


Ex. Long neck, gills, striped fur
Behavioral

Ex. Hibernation, hunting at night
Species
A group of organisms that can
mate with one another to
produce fertile offspring
Scientists believe that as Earth
changes species also change
or
Species die out
or
New species appear

Scientists observe that
species change over time
Evolution
The process in which populations
gradually change over time

Evidence of changes
Fossils
The remains or imprints of once-living
organisms found in layers of rock
 Fossil record
Timeline of when certain organisms existed
Made by studying fossils embedded in rock
 Fossils in newer rock layers more similar to
organisms today
 Older fossils less similar to today’s
organisms
 Part of fossil record is missing
Fossils are rare – few organisms will become
fossils


..
Evidence


Many organisms have common
characteristics
May have common ancestors
Evidence: Case Study =
Whale
Evidence in fossils links whales to
mammals that lived on land
To
 Organisms that partly lived on water
and partly on land
To
 An organism that lived in water
To
 Modern day whales

Evidence in skeletal structure
of today’s whale
Whales have hip bones!!
(whales do not walk)

When comparing organisms:
Evidence found :
In skeletal structures
 Structures and order of bones are
similar in organisms
When comparing DNA
 DNA in living organisms are similar
 More closely related organisms have
a greater amount of DNA in common
(chickens and dinosaurs)
