Transcript Evolution - Solon City Schools

Evolution- “Change Over
Time”
 All of the changes that have occurred in living things
since the beginning of life on Earth
History of the Earth
4.5 bya
3.5 bya
2.1 bya
• Earth forms
• 1st PROKARYOTES
st
•1
EUKARYOTES
700 million years ago…
 Evolution occurs over MANY generations
 Evolution occurs within POPULATIONS
(NOT individuals)
 Evolution involves genetic changes in a
SPECIES
– (Members of a species interbreed to produce
healthy, fertile offspring)
Evidence for Evolution
FOSSIL EVIDENCEProvides TRANSITIONAL LINKS
Archaeopteryxlinks reptiles and birds
Anatomical Evidence
ANALOGOUS
HOMOLOGOUS
STRUCTURES
STRUCTURES
structures that are similar
because they were inherited
from a COMMON ANCESTOR
similar in function, but NOT
inherited from a common
ancestor
NOTE: similar structure, but NOT
always function!
NOTE: similar FUNCTION, but not
STRUCTURE
In other words…
 Sometimes we see structures in two species
that are similar…some of them are:
– Homologous (they are similar because of a
common ancestor)
– Analogous (they are similar because althouth
they do NOT share a recent ancestor, they live
in similar environments and have adapted to
them similarly)
2 types of Evolution
Evolution Types
 Convergent Evolution
– Acquiring the same biological trait in
unrelated lineages
– These traits may be a result of occupying
similar environments.
Convergent Evolution
Evolution Types
 Divergent Evolution
– The accumulation of
differences between
groups which can lead
to the formation of new
species, usually a result
of different groups of
the same species
adapting to different
h
environments,
leading
to natural selection
defining the success of
specific mutations.
Divergent Evolution
More Anatomical Evidence:
Vestigial Structures
Vestigial Structures are
undeveloped structures
that were functional in
some ancestor, but are
no longer needed in that
organism.
EMBRYOLOGYsuggests common ancestors
BIOGEOGRAPHICAL
EVIDENCE
 When we study the distribution of plants and animals on
the planet, we notice:
– Animals evolved differently in each of the
biogeographical regions
– We see evidence that as the continents drifted,
organisms were separated and evolved.
BIOCHEMICAL EVIDENCE
 Almost all living things use the same
biochemical molecules
– DNA, Protein, ATP
 Vast diversity came about by only slight
differences in the same genes
 The more closely “related” the organisms are, the
more similar their DNA
Other Evidence…
 1. Mimicry and Camoflauge
 2. Antibiotic Resistance