Download Evidence of Evolution Pt 2

Warm-up Questions:
• What does the word speciation mean?
When natural selection leads to the
creation of a new species.
• What is the difference between homology
and analogy?
Homology are structures that are
similar in structure and share a
common ancestor. Analogy is
structures with similar functions that
do not share a common ancestor.
Evidence of Evolution Pt 2
Biogeography, cladograms
• The study of what organisms live where and why.
• Looks into the distribution of organisms on Earth, both
past and present, and of related patterns in the numbers
and kinds of living things.
Bio Geography:
• Phytogeography – The study of plants
• Zoogeography – The study of animals
• Microbial Biogeography – distribution of organisms over
space and time.
Specializations in Biogeography
• Geographic regions have characteristic groups of
organisms.
• Closely related organisms tend to be closer together than
more distantly related groups.
• Similar environments are found in different places on
Earth, BUT the same species may not be found in all.
• Not closely-related species in similar environments may
appear similar to each other due to convergent evolution,
but are not related.
Patterns Seen Across the Globe
• Divergent evolution
• Convergent evolution
Types of Change:
• When species that are similar and closely related become
increasingly different from each other. THEY
DIVERGE
• This is also called Adaptive Radiation because it has to do
with ADAPTING to different environments and
RADIATING out into different species.
Divergent Evolution:
mammal
Fish
• When distantly-related organisms evolve to become more
similar.
• occurs when unrelated species occupy similar
environments in different parts of the world.
Convergent Evolution:
• If organisms are well adapted to their environment, there
is no need for change.
• Fossil records show that some organisms have stayed
exactly the same or hardly changed at all through many
generations.
Stasis:
• Most organisms in the fossil
record do not contain transitional
forms.
• Instead, there is a sudden
appearance of a new form or
organism that had not previously
been seen in the fossils
Cambrian
Explosion
Sudden Appearance:
• The study of the evolutionary relationships of organisms.
• In phylogeny, we use diagrams called phylogenetic trees
and cladograms that show us how organisms are
classified based on their evolution.
Phylogeny:
• The root is the common ancestor to all of the organisms
shown in the tree.
• The descendants are the extant (present-living) organisms
from that ancestor.
Reading a Cladogram:
• The lineages are from the unique ancestor to the
descendent.
• This does not show all of the changes that occur along the
way.
Reading a Cladogram Contd:
Reading a Cladogram Contd:
• A clade is a grouping that includes an ancestor and ALL
of the descendants of that ancestor (whether extant or
extinct.)
Reading a Cladogram Contd:
A
.
B
.
D
.
C
.
E.
Which one(s) are clades?
• Cladograms show related organisms that share
adaptations derived through evolution.
• Derived shared characteristics: traits that appear through
evolution that were not present in earlier ancestors.
Reading a Cladogram Contd:
Live birth
• Which organisms in this cladogram have four limbs?
• Which organisms in this cladogram have four limbs AND
give live birth?
Reading a Cladogram Check
DIVERGENT
EVOLUTION
MORE RECENT COMMON
ANCESTOR
CONVERGENT
EVOLUTION
NOT A RECENT COMMON
ANCESTOR