1. Speciation and MacroEvolution
What is a species?

2. Thursday, March 5th
There are two rates at which speciation occurs. The debate is that new species arise either gradually or rapidly. Which process do you think to be more true?

3. Friday, March 6th
When two different species interbreed and have offspring, there can be complications with those particular offspring. What are some complications this new generation can have?

4. Announcements Things to turn in:
Hardy-Weinberg Practice Problems – DUE MONDAY, March 9th at the LATEST!
Lizard Virtual Labs – MONDAY!
2/23-2/27 – I need them MONDAY!
CH. 19 “Testing Yourself” #1-6, 12 + Add. Gen. Problems #1-3 – MONDAY!

5. NOW A SPECIAL GUEST TO TALK ABOUT AP TEST REGISTRATION…

6. 1) Deposit's this year are going to be $25
1)  Deposit's this year are going to be $25.00 for each AP exam a student takes, the actual cost of this year's exam is $91.00, up from last year.
2)  The deadline for collecting these funds is going to be March 10th.
3)  Ms. West will come in to collect the Deposits and give the "Talk" about exam expectations with preparation and such.
4)  Ms. West would really feel wonderful if she didn't have a line out her door on the last day of collecting deposits . . .please help make that possible.
5) Checks need to be written to Everett High School and the AP exam(s) the student is taking should be in the memo line.
6)  As in years past it is probable that students who are on free or reduced lunch will only have to pay the deposit, but I'll let Ms. West say for sure.  I also assume that the past practice of some financial help for students who are taking more than one AP exam but aren't on free or reduced lunch is still a possibility.

7. The final exam is an old AP test.
The only benefit you will receive from taking the final exam in this class is it gets added to your semester grade at 20%. (And is that really a benefit? See your 1st semester exam grade.)
The benefits you will receive by taking the AP test include, but are not limited to: undying love and affection, experience of taking a college level exam, possibility of college credit, and being “exempt” from the actual exam day during 6th hour, and a food treat to be determined.

8. Species What is a species?
Biological species concept: Population whose members can interbreed & produce viable, fertile offspring
Reproductively compatible
Defined by Ernst Mayr

9. What is Speciation? The origin of new species in evolution
A species is spilt into two or more species or the transformation of one species into a new species over time
Speciation is the final result of changes in a gene pool allele and genotypic frequencies

10. How and Why Do New Species Originate?
Species are created by a series of evolutionary processes
Populations become isolated:
Geographically isolated
Reproductively isolated
Isolated populations evolve independently
Types of Isolation
Allopatric = geographic separation
Sympatric = still live in same area

12. Reproductive Isolation Mechanisms
Any structural, functional, or behavioral characteristics that prevents successful reproduction
Pre-Zygotic or “Pre-Reproduction” Barriers:
Behavioral isolation
Geographic isolation
Ecological isolation
Temporal isolation
Mechanical isolation
Gametic isolation

13. Geographic Isolation Species occur in different areas physical barrier
Allopatric speciation: Population becomes separated by geographic barrier (River, Lake, Mountain, etc.)

14. Harris’s antelope squirrel inhabits the canyon's south rim (L)
Harris’s antelope squirrel inhabits the canyon's south rim (L). Just a few miles away on the north rim (R) lives the closely related white-tailed antelope squirrel.

15. Ecological Isolation
Species occur in same area, but occupy different habitats so rarely encounter each other
Ex. lions & tigers could hybridize, but they live in different habitats:
lions in grasslands
tigers in rainforest

16. Temporal Isolation
Species that breed during different times of day, different seasons, or different years cannot mix gametes
Sympatric speciation: Develops into two or more reproductively isolated groups without prior geographic isolation
Polyploidy: containing more that two paired sets of homologous chromosomes

18. Behavioral Isolation
Unique behavioral patterns & rituals isolate species
Identifies members of species
Attract mates of same species
Ex. courtship rituals, mating calls, pheromones, etc.
Blue-Footed Boobies select their mates only after an elaborate courtship ritual has be performed.

19. Mechanical Isolation
Morphological differences can prevent successful mating
In animals genitalia is unsuitable for one another to mate; incompatible
In plants, structural components create an accessibility to pollen to certain pollinators; prevents cross-fertilization

20. Plants Even in closely related species of plants, the
flowers often have distinct
appearances that attract
different pollinators.
These 2 species of monkey
flower differ greatly in
shape & color, therefore
cross-pollination does not
happen.
Plants

21. Insects For many insects, male & Lack of “fit” between sexual organs:
female sex organs of
closely related species do
not fit together, preventing
sperm transfer
Lack of “fit” between sexual organs:
hard to imagine for us… but a big issue
for insects with different shaped
genitals!

22. Gametic Isolation
Sperm of one species may not be able to fertilize eggs of another species mechanisms
Biochemical barrier: sperm cannot penetrate egg
receptor recognition: lock & key between egg & sperm
Chemical incompatibility: sperm cannot survive in female reproductive tract

23. Sea urchins release sperm & eggs
into surrounding waters where they
fuse & form zygotes. Gametes of
different species are unable to fuse.

24. Post-Reproduction Barriers
“Post-Zygotic”
Prevent hybrid offspring from developing into a viable, fertile adult
reduced hybrid viability
reduced hybrid fertility
hybrid breakdown

25. Reduced Hybrid Viability (Zygote Mortality)
Genes of different parent species may interact & impair the hybrid’s development
Species of salamander
genus, Ensatina, may
interbreed, but most
hybrids do not
complete development
& those that do are
frail.

26. Reduced Hybrid Fertility (Hybrid Sterility)
Even if hybrids are vigorous they may be sterile
Chromosomes of parents may differ in number or structure & meiosis in hybrids may fail to produce normal gametes

28. Hybrid Breakdown (F2 Fitness)
Hybrids may be fertile & viable in first generation, but when they mate offspring are feeble or sterile
In strains of cultivated rice,
hybrids are vigorous but
plants in next generation
are small & sterile.
“Parents” on path to
separate species.

29. Rate of Speciation Current debate:
Does speciation happen gradually or rapidly?
Gradualism (Phyletic Gradualism)
Charles Darwin
Charles Lyell
Punctuated Equilibrium
Stephen Jay Gould
Niles Eldredge

30. Gradualism Gradual divergence over long spans of time
Assume that big changes occur as the accumulation of many small ones

31. Punctuated Equilibrium
Rate of speciation is not constant
rapid bursts of
change
long periods of little
or no change
species undergo
rapid change when
they 1st bud from
parent population

32. Evolution is not goal-oriented!
An evolutionary trend does NOT mean that evolution is goal-oriented.
Surviving species do NOT represent the peak of perfection. There is compromise & random chance involved as well.
Remember that for humans as well!

34. Speciation Article 1st Step: Unpacking the title
What are we going to be reading about?
What key words should I investigate
What things don’t I know? What do I know for sure?
2nd Step: Reading for Information
3rd Step: Summative Analysis of Infomartion

35. Speciation Article
Evidence:
Interpretation:

36. Questions