Lecture 8- Reconstructing and using phylogenies II Flashcards
What is it called when plants reproduce by mating with another individual?
Outcrossing
What do many outcrossing species have?
Mechanisms to prevent self fertilization
What are species who have mechanisms to prevent self fertilization called?
Self- incompatible
What are species who regularly fertilize themselves with their own pollen called?
Selfing species
They are self compatible
How can it be established how many times self compatibility has evolved in a group of plants?
Conducting a phylogenetic analysis of outcrossing and selfing species
In what genus and family has the evolution of fertilization mechanisms been examined?
Linanthus (genus)
Phlox (family)
Linanthus is a group of plants with _______ breeding systems and pollinating systems.
Diverse
What does petals does the outcrossing/self incompatible species in Linanthus have and what is it pollinated by?
Long petals
Pollinated by long tongue flies
What petals does the self-compatible species of Linanthus have?
Short petals
How many species of Linanthus were involved in the phylogenetic study?
12
What information was used to reconstruct the phylogeny of Linanthus?
Nuclear ribosomal DNA sequences
How was it determined what species were self compatible?
Artificially pollinating flowers with the plants own pollen or with pollen from other individuals and observing if viable seeds were formed
Self incompatibility is:
a.Derived state
b.Ancestral state
In the genus Linanthus
B
Ancestral state
How is the self incompatibility found in the Linanthus genus unusual?
Multiple origins of self-incompatibility has not been found in any other flowering plant family
Why is it easier to change from self-incompatible to self-compatibility than the reverse change?
Self incompatibility depends on physiological mechanisms in both pollen and stigma and requires the presence of at least 3 alleles
How is the physical aspect of self incompatibility in Linanthus unusual?
The pollen rejection site is the stigma
Site of pollen rejection vary greatly among other plant families
How many times has self incompatibility evolved in Linanthus?
3 times
Why were the different self compatible Linanthus species that were classified as one species now classified as separate species?
Phylogenetic analysis using ribosomal DNA showed them to be members of distinct lineages
What are zoonotic diseases?
Diseases caused by infectious organisms that have been transferred to humans from another animal host
What did phylogenetic analysis of immunodeficiency viruses show?
Humans acquired these viruses from two different hosts
Where was HIV-1 acquired from?
Chimpanzees
Where was HIV-2 acquired from?
Mangabeys
Where is the HIV-1 form of the virus more common and why?
Human populations in central Africa
Where chimpanzees are hunted for food
Where is the HIV-2 form of the virus more common and why?
West Africa
Sooty mangabeys are hunted for food
What does the distribution of HIV viruses infer about how HIV entered the human population?
Viruses entered human population through hunters who cut themselves while skinning chimpanzees/ sooty mangabeys
What is the genus that swordtail fish belong in?
Xiphophorus
What do male swordtails have that is associated with reproductive success?
Long, colorful extensions of the tail
Male swordtails with long swords are more likely to mate successfully than males with short swords. This is an example of…
Sexual selection
What is the sensory exploitation hypothesis?
Swords exploit a preexisting bias in the sensory system of the females
What was used to identify the closest relatives of swordtails before the evolution of the sword?
A phylogeny
What is the closest relative to swordtails?
platyfishes (another group of Xiphophorus)
How was the sensory exploitation hypothesis tested?
Attaching artificial swordlike structures to some male platyfishes- females preferred this, supporting the hypothesis
Why is a new flu vaccine needed every year?
Rate of evolution of the Influenza virus is so high that flu viruses that circulate each year are substantially different to previous years
What is hemagglutinin?
A protein on the surface of influenza viruses that is recognized by the human immune system
What does phylogenetic analysis of influenza strains indicate?
- Strong selection by human immune system against most strains
- Strains with greatest number of amino acid replacements on hemagglutinin are likely to survive
How do biologists predict which of the currently circulating strains of Influenza virus are most likely to survive and leave descendants in the future?
By conducting phylogenetic analysis of hemagglutinin
Who started the biological classification system and when?
Carolus Linnaeus
mid 1700s
What is the name of system of biological classification created by Carolus Linnaeus?
Binomial nomenclature
What is the advantage of binomial nomenclature?
Scientists can unambiguously refer to the same organisms by the same names
Define genus.
A group of related, similar species recognised by taxonomists with a distinct name used in nomenclature
In the Linnaean system, how are species and genera further grouped?
A hierarchical system of higher taxonomic catagories
Name the taxonomic categories.
Kingdom Phylum Class Order Family Genus Species (kinky people can often find good sex)
What is a limitation of the Linnaean system categorizing organisms?
Ranked levels of classification is subjective
Used largely for convenience
What are biological classification systems used to express?
Relationships among organisms
Define monophyletic.
The taxon contains an ancestor and all decedents of that ancestor, and no other organisms. (also known as a clade)
What is a group that does not include the common ancestor referred to as?
polyphyletic group
What is a group that does not include all the descendants of a common ancestor referred to as?
A paraphyletic group
Why do some classifications still used today still include para and poly phyletic groups?
Some organisms have not been evaluated phylogenetically.
When more than one name is proposed to name a species, what do the rules specify the name should be?
The name first proposed
Why are there duplicated names in taxonomy?
Historical separation of zoology, botany and microbiology
Give an example of duplicated names arising from historical separation of fields within biology.
Drosophilia is a genus of fruit flies and a genus of fungi
