1. Macroevolution Series of microevolution
Speciation – the formation of new species when one ancestral species evolves more than 1 typical descendant.
Since speciation occurs when one species evolves into more than 1 new species, it increases the number of species that exist.

2. Patterns of Macroevolution
These are theories/models of evolution
A. Mass Extinctions
B. Adaptive Radiation
C. Convergent Evolution
D. Coevolution
E. Gradualism
F. Punctuated Equilibrium

3. Patterns of Macroevolution
Species
that are
Unrelated
Related
form in
under
under in in
Intense environmental pressure
Inter-relationships
Similar environments
Small populations
Different environments
can undergo
can undergo
can undergo
can undergo
can undergo
Convergent evolution
Punctuated equilibrium
Adaptive radiation
Coevolution
Extinction

4. Mass Extinctions
Event in which many types of living things became extinct at the same time. 
Period in which huge numbers of species disappeared.
Whole ecosystems were wiped out
Left habitats/niches open
Resulted in burst of evolution of new species in new habitat
Disrupted energy flow throughout the biosphere and caused food webs to collapse

5. Mass Extinctions Possible causes Asteroids hitting earth
Volcanic eruptions
Continental drift
Sea levels changing

6. Adaptive Radiation
The evolution of an ancestral species, which was adapted to a particular way of life, into many diverse species, each adapted to a different habitat
Many new species diversify from a common ancestor .
The branching out of a population through variation.
The new species live in different ways than the original species did.

7. Adaptive Radiation

8. Convergent Evolution
Opposite of divergent evolution (adaptive radiation)
Unrelated organisms independently evolve similarities when adapting to similar environments, or ecological niches
Analogous structures are a result of this process
Example: penguin limb/whale flipper/fish fin
The wings of insects, birds, pterosaurs, and bats all serve the same function and are similar in structure, but each evolved independently

9. Convergent Evolution

10. Convergent Evolution

11. Convergent Evolution
Similar body shapes and structures have evolved in the North American cacti...and in the euphorbias in Southern Africa

12. Coevolution The mutual evolutionary influence between two species
When two species evolve in response to changes in each other
They are closely connected to one another by ecological interactions (have a symbiotic relationship) including:
Predator/prey
Parasite/host
Plant/pollinator
Each party exerts selective pressures on the other, thereby affecting each others' evolution

13. Coevolution

14. Coevolution
Praying Mantis simulates plant to protect itself from predators and eats pests that are attracted to and feed on the plant, so it protects the plant.

15. Gradualism
The evolution of new species by gradual accumulation of small genetic changes over long periods of time
Emphasizing slow and steady change in an organism
Occurs at a slow but constant rate
Over a short period of time it is hard to notice

16. Gradualism

17. Gradualism

18. Punctuated Equilibrium
Stable periods of no change (genetic equilibrium) interrupted by rapid changes involving many different lines of descent
Opposite of gradualism
It is rare, rapid events of branching speciation
Characterized by long periods of virtual standstill ("equilibrium"), "punctuated" by episodes of very fast development of new forms

19. Punctuated Equilibrium

20. Gradualism or Punctuated Equilibrium

21. Why won’t our lungs evolve to deal with air pollution?
Limits to adaptation:
A change in the environment can only lead to adaptation for traits already present in the gene pool
Reproductive capacity may limit a population’s ability to adapt
If you reproduce quickly (insects, bacteria) then you can adapt to changes in a short time
If you reproduce slowly (elephants, tigers, corals) then it takes thousands or millions of years to adapt through natural selection
Most individuals without trait would have to die in order for the trait to predominate and be passed on

22. When faced with a change in environmental condition, a population of a species can:
Adapt via natural selection
Migrate (if possible) to an area with more favorable conditions (Mars & Atlantis?)
Become extinct
Natural selection can only act on inherited alleles already present in the population—do not think that the environment creates favorable heritable characteristics!

23. Three types of Natural Selection
Directional
Allele frequencies shift to favor individuals at one extreme of the normal range
Only one side of the distribution reproduce
Population looks different over time
Peppered moths and genetic resistance to pesticides among insects and antibiotics in bacteria
Stabilizing
Favors individuals with an average genetic makeup
Only the middle reproduce
Population looks more similar over time (elim. extremes)
Diversifying
Environmental conditions favor individuals at both ends of the genetic spectrum
Population split into two groups

24. Coevolution Interactions between species can cause microevolution
Changes in the gene pool of one species can cause changes in the gene pool of the other
Adaptation follows adaptation in something of a long term “arms race” between interacting populations of different populations
The Red Queen Effect
Can also be symbiotic coevolution
Angiosperms and insects (pollinators)
Corals and zooxanthellae
Rhizobium bacteria and legume root nodules

25. Niches A species functional role in an ecosystem
Involves everything that affects its survival and reproduction
Includes range of tolerance of all abiotic factors
Trophic characteristics
How it interacts with biotic and abiotic factors
Role it plays in energy flow and matter cycling
Fundamental Niche
Full potential range of physical chemical and biological conditions and resources it could theoretically use if there was no direct competition from other species
Realized Niche
Part of its niche actually occupied
Generalist vs. Specialist
Lives many different places, eat many foods, tolerate a wide range of conditions vs few, few, intolerant…
Which strategy is better in a stable environment vs unstable?

26. Niche Overlap separation Number of individuals Generalist species
Region of
niche overlap
Generalist species
with a broad niche
with a narrow niche
Niche
breadth
separation
Number of individuals
Resource use

27. Competition Shrinks Niches

28. Key Concepts:
A species consist of one or more populations of individuals that can interbreed and produce offspring
Populations of a species have a shared genetic history
Speciation is the process by which daughter species evolve from a parent species

29. Key Concepts: Geographic barriers can start the process of speciation
Allopatric speciation
With sympatric speciation, a species can form within the range of a parent species
Parapatric speciation has adjacent populations becoming distinct species while still coming in contact along a common border

30. What is a Species? Morphological Species Concept
Based on appearance alone
Biological Species Concept
A species is one or more populations of individuals that are interbreeding under natural conditions and producing fertile offspring, and are reproductively isolated from other such populations

31. Speciation Two species arise from one Allopatric Sympatric
Requires Reproductive isolation
Geographic: Physically separated
Temporal: Mate at different times
Behavioral: Bird calls / mating rituals
Anatomical: Picture a mouse and an elephant hooking up
Genetic Inviability: Mules
Allopatric
Speciation that occurs when 2 or more populations of a species are geographically isolated from one another
The allele frequencies in these populations change
Members become so different that that can no no longer interbreed
See animation
Sympatric
Populations evolve with overlapping ranges
Behavioral barrier or hybridization or polyploidy

32. Reproductive Isolating Mechanisms
Any heritable feature of body, form, functioning, or behavior that prevents breeding between one or more genetically divergent populations
Prezygotic or Postzygotic

33. Pre-Zygotic Isolation
Mating or zygote formation is blocked
Temporal Isolation
Behavioral Isolation
Mechanical Isolation
Ecological Isolation
Gamete Mortality

34. Post-Zygotic Isolation
Hybrids don’t work
Zygotic mortality - Egg is fertilized but zygote or embryo dies
Hybrid inviability - First generation hybrid forms but shows low fitness
Hybrid infertility - Hybrid is fully or partially sterile

35. Speciation Northern Arctic Fox Spreads northward and
Adapted to heat
through lightweight
fur and long ears,
legs, and nose, which
give off more heat.
Adapted to cold
through heavier
fur, short ears,
short legs, short
nose. White fur
matches snow
for camouflage.
Gray Fox
Arctic Fox
Different environmental
conditions lead to different
selective pressures and evolution
into two different species.
Spreads
northward
and
southward
separates
Southern
population
Northern
Early fox

36. Allopatric Speciation
Physical barrier prevents gene flow between populations of a species
Archipelago hotbed of speciation

37. Allopatric Speciation
New arrival in species
Poor habitats on an isolated archipelago
Start of allopatric speciation
Hawaiian Honeycreepers

38. Sympatric Speciation New species forms within home range
Polyploidy leads to speciation in plants
Self-fertilization and asexual reproduction

39. Extinction
The ultimate fate of all species just as death is for all individual organisms
99.9% of all the species that have ever existed are now extinct
To a very close approximation, all species are extinct
Background vs. Mass Extinction
Low rate vs % of total
Five great mass extinctions in which numerous new species (including mammals) evolved to fill new or vacated niches in changed environments
10 million years or more for adaptive radiations to rebuild biological diversity following a mass extinction

40. Extinction in the context of Evolution
If the environment changes rapidly and
The species living in these environments do not already possess genes which enable survival in the face of such change and
Random mutations do not accumulate quickly enough then
All members of the unlucky species may die

41. Species and families experiencing mass extinction years ago Period Era
Ordovician: 50% of animal families,
Devonian: 30% of animal families,
Permian: 90% of animal families, including
over 95% of marine species; many trees,
amphibians, most bryozoans and
brachiopods, all trilobites.
Triassic: 35% of animal families, including
many reptiles and marine mollusks.
Cretaceous: up to 80% of ruling
reptiles (dinosaurs); many marine
species including many
foraminiferans and mollusks.
Current extinction crisis caused
by human activities.
Species and families experiencing
mass extinction
Bar width represents relative
number of living species
Extinction
Millions of
years ago
Period
Era
Paleozoic
Mesozoic
Cenozoic
Quaternary
Tertiary
Cretaceous
Jurassic
Triassic
Permian
Carboniferous
Devonian
Silurian
Ordovician
Cambrian
Today 65
180
250
345
500