Lecture 20 Flashcards
1
Q
Plato
A
- thought that true knowledge wasn’t present on our planet but in a transcendental plane of ideas
- true knowledge comes from the knowledge of the Idea
- the world of ideas is populated with types which are discrete, immutable and ideal representations of things that exist
2
Q
Aristotle
A
- thought we learn about truth from this planet
- thought true knowledge was empirical comes from real world=essentialism
- organisms have essential features they have a predisposition to produce organisms of its kind
3
Q
Ladder Thinking (Similar to Neoplatonists “Great Chain of Being”)
A
- wrong idea
- first hit on Google
- inevitable progression toward complexity-species destined to become more complex
- can see the other species in the ladder still living together today: weird because there must be several life origins to be able to see the monkey that is thought to have evolved into another species
- no extant species transform into another extant species (i.e. chips transform into the human with time)
4
Q
Relatedness
A
- defined in time since most recent common ancestor
- has nothing to do with alleles
- genetic similarity is just a byproduct of relatedness; it’s not how you define relatedness
5
Q
Ideas that Darwin proposed matched Linneasus’ classification
A
- not a coincidence
- it’s how life evolved
- speciation events happen at teh nodes
6
Q
Phylogenetic Species Concept
A
- works with sexual and asexual organisms
- emphasizes phylogenetic history of a group
- a species is an irreducible cluster of individuals that is diagnosably distinct from other clusters, and within which there is a parental pattern of ancestry and descent
- so species A is defined by the specific alleles its individuals have at different loci and individuals from species B would have different alleles
7
Q
To have reduction in gene flow need isolating barriers
A
- can happen premating or postmating
- can happen prezygotic or postzygotic
- premating is prezygotic by definition
8
Q
Premating
A
- means they don’t mate
- can be sexual or environmental in nature
9
Q
True or False: pair of siblings more genetically similar than a pair of cousins, therefore siblings are more closely related
A
- false
- relatedness is defined in time since most recent common ancestor
10
Q
Tree Thinking
A
- NO SUCH THING AS EXTANT SPECIES BEING MORE OR LESS EVOLVED/BASAL THAN ANOTHER EXTANT SPECIES
- all extinct species can be more basal
11
Q
Linneaus’ and Common Descent
A
- linnaeus system was proposed way before idea of common descent appeared in Darwin’s book
- Linnaeus was not thinking about common descent, but he observed that animals could be classified in a hierarchical way
- look at graphic and be able to reproduce and compare to tree
12
Q
Species and Speciation
A
- speciation happens at nodes on a tree diagram
- the definition of species is a convention, sometimes it works well and sometimes it doesn’t.
13
Q
Typological or Essentialist Species Concept
A
- a speices has a set of recognizable essential characteristics that define it
- we can choose an individual that we believe is “representative” of that species and we call it the species “type”
- but how do you choose the type?
14
Q
Biological Species Concept (BSC)
A
- considers that a species is a group of populations that is evolving independently of other species
- “species are groups of actually or potentially interbreeding populations, which are reproductively isolated from other such groups”
- gene flow is reduced but may exist at low levels between two different species (100% reproductive isolation not required)
- means that hybrids may be formed and may be viable/fertile, but would still have 2 species
- doesn’t work with bacteria because of asexual nature
15
Q
Gene Flow
A
- movement of alleles from one population to another
- individuals migrate from one population to another and reproduce
- pollen and seeds can be carried by wind/pollinators
