1. The document discusses macroevolution and systematics, including definitions of microevolution, macroevolution, and species. It also covers speciation, the formation of new species, which can occur through allopatric, parapatric, or sympatric mechanisms. 2. Speciation is a two-step process involving first reproductive isolation between populations followed by genetic divergence to the point where interbreeding is no longer possible. Speciation can result in anagenesis, the evolution of one species into another over time, or cladogenesis, where one species forms two or more new species. 3. Rates of speciation depend on the number of unfilled niches, and adaptive radiation is when a small

1. MACROEVOLUTION & SYSTEMATICS:
CHAPTER 5

2. DEFINITIONS
Microevolution: genetic
change in a population from
one generation to the next
Macroevolution: Processes
through which new species
arise

3. WHAT IS A SPECIES?
 Biological species concept: If
organisms from two populations are
capable of breeding naturally and
can produce fertile offspring, then
they are classified in the same
species.
X =
Horse Donkey Mule

4. SPECIATION
 The formation of new species
 Gene flow keeps populations
similar to one another.
 Reproductive Isolation:
genetic isolation of
populations that may cause
them to become incapable of
producing fertile offspring.
 Gene flow is the glue that
holds species together.

5. SPECIATION: A TWO STEP PROCESS
1. Reproductive Isolation
 Reduction of gene flow provides
opportunity for speciation
 Does not always lead to speciation
2. Genetic Divergence
 Other evolutionary forces change
population enough so that fertile
interbreeding is no longer possible

6. ANAGENESIS: “STRAIGHT-LINE”
EVOLUTION
Single species
evolving into
new species
over time

7. CLADOGENESIS: “BRANCHING”
EVOLUTION
 Formation of
one or more
new species
from another
over time

8. 3 TYPES OF SPECIATION
1. Allopatric speciation-speciation in
organisms with no geographic
overlap.
2. Parapatric speciation-speciation in
organisms with partial geographic
overlap.
3. Sympatric speciation-speciation in
organisms with complete geographic
overlap.

9. ALLOPATRIC SPECIATION

10. MODELS OF SPECIATION

11. PARAPATRIC SPECIATION

12. SYMPATRIC SPECIATION

13.  Niche: the way of life of a
species (How that species fits
into the surrounding
environment)
 Niche partitioning: species
evolve to occupy different
niches and avoid competition
 Ex. occupying different
places in the habitat, feeding
at different times, being
active at different times of
the year, etc.
 Bees and moths use the
same food resource
 Bees diurnal, Moths
nocturnal
☼ Can’t have two species occupying
the same niche in the same area
because this will lead to
competition.

14. NICHE
PARTITIONING

15. SPECIATION RATE
Rate of Speciation: depends on
# of empty niches
Adaptive Radiation: Rapid
diversification by a small # of
species to fill many open niches

20. TEMPO OF EVOLUTION
Gradualism: Macroevolution is
a relatively slow and gradual
process.
Punctuated Equilibrium: Long
intervals of time with little
change (stasis) interspersed
with short intervals of rapid
evolutionary change.

21. THE BIRTH OF SPECIES
b) Gradualism with
increase in rate of
change
a) Gradualism c) Punctuated
Equilibrium =
Staircase pattern

22. EXTINCTION
 The disappearance
of a group of
organisms such as a
species.
 When a species
cannot change fast
enough to adapt to
changes in its
environment, it may
become extinct.

23. NEARLY EVERYTHING THAT HAS EVER LIVED IS EXTINCT

24. PALEOSPECIES
Paleospecies: Identified in the
fossil record based on
physical similarities to and
differences from other species
Assumption: physical similarity
= genetic relatedness

26. CLASSIFICATION
Classification is used to
order organisms into
categories to show
evolutionary relationships.

27. LINNAEAN SYSTEM OF CLASSIFICATION
 Hierarchical classification
 Involves a number of
categories and
subcategories reflecting
evolutionary relationships
 Kingdom
 Phylum
 Class
 Order
 Family
 Genus
 Species
Carl Linnaeus

29. HOW CAN WE MAKE SENSE OF ALL OF
THIS DIVERSITY?

30. PHYSICAL SIMILARITIES ARE ONLY USED TO CLASSIFY ORGANISMS
IF THEY REFLECT EVOLUTIONARY RELATIONSHIPS
 Analogous
traits: Traits
similar due
to common
function
 Homologous
traits: Traits
similar due
to common
ancestry

31. NOT ALL HOMOLOGOUS TRAITS ARE
EQUALLY USEFUL FOR CLASSIFICATION
 Ancestral trait: Trait
appearing early in
the evolution of a
lineage
 Derived trait: Traits
that are modified
from the ancestral
condition

32. USING DERIVED TRAITS TO BUILD
PHYLOGENIES
Derived (Homologous) Analogous Traits Ancestral Traits
Traits

33. EVOLUTION OF THE COOTIEMOUTH
(PHYLOGENETIC TREE)

34. QUESTIONS
1. What is a phylogeny?
2. What is the difference between analogous and
homologous traits?
3. What is the difference between ancestral and
derived traits
4. What is the difference between microevolution
and macroevolution?
5. What is the biological species concept?
7. What are allopatric, parapatric, and sympatric
speciation?
8. What is an adaptive radiation?
9. How do you identify a paleospecies and what are
the problems with this method?

35. HAVE A NICE DAY!