Lectures 3-5 Flashcards
What is the role of phylogenetics?
to study the evolutionary relationships among species
What is a phylogenetic tree?
What do they show?
-graphical representations of evolutionary relationships among species
-show common ancestors and branching patterns of descent
Define monophyletic trees
trees that include all descendants coming of a given common ancestor, forming a complete branch of an evolutionary tree
Define paraphyletic trees
trees that include a common ancestor but not all of it’s possible descendants
Define polyphyletic trees
trees that do not include the common ancestor of the listed taxa
What are synapomorphies?
Traits shared by two distinct taxa because they were inherited from a common ancestor
What are autapomorphies?
traits which have recently emerged
-this means they are present in only one of two “sister taxa”.
-a “derived trait”
What does phylogeny give rise to?
-descendant groups
-populations
-species
-taxa
What does phylogeny rely upon?
-shared traits (genotypic and phenotypic)
-the ability to quantify and compare them
How are phylogenetic trees generated?
by computational biology methods/models
What is a clade?
a group of species that share a common ancestor
-they can vary in size, either narrow or broad.
What is the significance of endpoints on a phylogenetic tree?
-can be used to assess the relatedness of species
-indicate which taxa are more closely related based on branching patterns
What do branches of a phylogenetic tree represent?
-represent evolutionary time
-show how long each taxon has been separated from a common ancestor
How are phylogenies represented?
-trees
-ladders
What is a monophyletic group?
a group that includes all descendants coming after a given common ancestor
What is a paraphyletic group?
a group that includes a common ancestor but not all possible descendants
What is a polyphyletic group?
a group that does not include the common ancestor of the listed taxa
What is the difference between synapomorphies and autapomorphies?
-Synapomorphies are shared traits inherited from a common ancestor
-Autapomorphies are recently emerged traits present in only two “sister taxa”
Define EDGE species
species that are both unique in their evolutionary history and at risk of extinction
What is the main way of identifying common ancestors?
identified at nodes where branches split on the phylogenetic trees
Define Character acquisition
the process by which species develop new traits or characteristics over evolutionary time
What is the product of “successful” evolution?
biodiversity
Define Biodiversity
variability among living organisms from all sources including terrestrial, marine and other aquatic ecosystems and their ecological complexes
What does biodiversity include?
-diversity within species, between species and of ecosystems
Why is understanding the concept of a “species” important in biodiversity?
species are fundamental units that contribute to biodiversity and evolution
Define species
a class of plants or animals whose members have the same main characteristics and are able to breed with each other
What is Biological Species Concept (BSC)?
a concept that defines species based on their ability to interbreed and produce healthy offspring
What are the limitations of traditional definitions for species?
do not account for species that can interbreed and produce viable hybrid offspring
What is the PSC definition of species?
emphasises the evolutionary history and relationships among organisms
Provide an example of two species that can interbreed
The Coyote and the Wolf
Define taxonomy
the process of naming, defining and classifying groups of biological organisms based on shared characteristics
What is the hierarchy of biological taxonomy?
-Domain
-Kingdom
-Phylum
-Class
-Order
-Family
-Genus
-Species
Define Taxa
groups of biological organisms classified based on shared characteristics
What is the Typological Species Concept?
a species concept that classifies organisms based on morphological traits and fixed characteristics
What is the Ecological Species Concept?
defines species in terms of their ecological niche and role in the environment
What are the two commonly used definitions for the term “species”?
BSC
PSC
What is Cohesion Species Concept?
a species concept that emphasises the genetic and ecological cohesiveness of a species
What is a genetic exchange between different species called?
hybridisation
What does Reproductive Species Concept focus on?
the mechanisms that prevent species from inbreeding
Name 2 cichlid species that can hybridise
-Midas cichlid
-Redhead cichlid
Define Isolation Species Concept
a species concept that centres on mechanisms that isolate species, leading to speciation
Why does taxonomy matter in biology?
it helps organise and classify biological organisms
-this makes it easier to study and understand biodiversity
Define Evolutionary Species Concept
the smallest monophyletic groups in the tree of life
