Species Concepts (5) Flashcards
Species (in general)?
= organisms that can reproduce naturally with each other & produce fertile offspring.
How do we distinguish species?/ What criteria should we use to distinguish species? (4)
• Morphology.
• Habitat (ecological niche).
• Ability to interbreed.
• Common ancestry/Relatedness (Genetics).
List the Species Concepts (SC)? (7)
• Morphological SC.
• Phenetic SC.
• Biological SC.
• Recognition SC.
• Ecological SC.
• Evolutionary SC.
• Phylogenetic SC.
Morphological SC?
= species is a group of organisms with similar morphological & anatomical characteristics, but are different from other species.
Eg of Morphological SC?
Genus Panthera (“predator of all”) has 4 species (tiger, lion, leopard, cheetah) which differ in pattern, size & skull anatomy.
What does the “most recent” Phenetic SC include?
Quantitative measurements.
What enables you to place individuals in any 1 species?
Diagnostic characters (data types).
Explain the 2 data types?
● Categorical
= grouped.
● Continuous
= data that can take on any value.
Pros of Morphological SC? (3)
• Applies to sexual & asexual organisms (including bacteria).
• Applies to fossils for macroevolutionary studies.
• Enables comparison of fossils & current species.
Cons/Problems of MSC? (4)
• Variation within a species.
• Cryptic species.
• Lack of morphological differences between species.
• Sexual dimorphism.
Biological SC?
= species are members of populations that actually or potentially interbreed in nature.
Eg of BSC? Explain.
Western & Eastern Meadowlarks
- Look similar but don’t interbreed.
- Have different mating songs.
Kinds of reproductive isolating mechanisms? (2)
• Premating/Prezygotic mechanisms.
• Postmating/Postzygotic mechanisms.
List the Premating/Prezygotic mechanisms? (5)
• Ecological/Habitat isolation.
• Seasonal/Temporal isolation.
• Sexual/Behavioral isolation.
• Mechanical isolation.
• Gametic isolation.
Gametic isolation?
= where there is molecular incompatibility of the sperm & egg.
Premating/Prezygotic mechanisms = …?
Gamete related.
List the Postmating/Postzygotic mechanisms? (3)
• Hybrid inviability.
• Hybrid sterility.
• Hybrid breakdown.
Hybrid inviability?
= wherr zygotes are less viable.
Hybrid breakdown?
= where the F2 hybrids are less viable.
Egs of Hybrid sterility? (2)
• Liger (Lion+Tiger).
• Mule (Donkey+Horse).
Cons/Problems of BSC? (5)
• “Potentially interbreeding” suggests separate species & is difficult to determine.
• Asexually reproducing organisms.
• Ring species.
• Chronospecies.
• Hybrids.
Egs of Asexually reproducing organisms as a problem of Biological SC? (2)
• Aspergillus fungi.
• Bacteria.
Ecological SC?
= species is a set of organisms exploiting the same ecological niche.
What controls the division of resources in Ecological SC? (2)
• Ecological processes.
• Evolutionary processes.
Type of selection associated with Ecological SC?
Disruptive selection.
Outcome of Disruptive selection in Ecological SC?
Species formation (speciation).
Why is Disruptive selection associated with Ecological SC?
Why should ecological processes produce discrete species?
Disruptive selection.
Egs of Ecological SC? (3)
• Larvae of maggot flies on Apple & Hawthorn.
• Nematodes (one in humans, other in pigs).
• Dwarf chameleons (one in Western Cape, other in Knysna).
Pros of Ecological SC? (2)
• Apply to hybrids.
• Applies to sexual & asexual organisms.
Cons/Problems of Ecological SC? (3)
• Can miss cryptic species.
• Niches tend to be assumed & difficult to fully define.
• Many taxa exploit overlapping resources, or can switch if a resource becomes scarce.
Eg of Pros of Ecological SC?
Dwarf chameleons.
Phylogenetic SC?
= species is the smallest set of organisms that share an ancestor and are different from other sets.
What is Phylogenetic SC based on?
Character data (morphology + genetics).
What does Phylogenetic SC comprise of?
Speciation events.
Monophyletic?
= group of organisms share exclusive common ancestors.
Do populations share unique derived traits that cause them to cluster together on the tips of a Phylogenetic tree?
It is rare as one needs a really,really good Phylogenetic tree.
Synapomorphy?
= shared derived characters.
Eg of Phylogenetic SC?
Asian & African elephants (divide further into African forest & savanna elephants).
Cons/Problems of Phylogenetic SC? (2)
• Leads to over-splitting as more and more characters are used.
• Hybridization.
Application of Phylogenetic SC?
Polar bears & Brown bears clade (with them not being distinct species).
Does it matter which SC we apply?
Yes.
Why does it/Why does it not matter what SC we apply?
It matters because it determines the number of species present within a population.
Egs of species? (3)
• Happy faced spiders.
• Monarch butterflies.
• Pheidole barbata (ants).
Why are Happy faced spiders classified as one species even though they are so different?
They interbreed.
Which Species Concepts are classified under Morphology? (2)
• Morphological SC.
• Phenetic SC.
Which Species Concepts are classified under Interbreeding? (2)
• Biological SC.
• Recognition SC.
Which Species Concept is classified under Ecological niche?
Ecological SC.
Which Species Concepts are classified under Common ancestry/Relateness (Genetics)? (2)
• Evolutionary SC.
• Phylogenetic SC.
Data types? (2)
• Categorical data.
• Continuous data.
Egs of Variation within a species as a problem for MSC? (2)
• Happy faced spiders.
• Harlequin ladybird.
Egs of Sexual dimorphism as a problem for MSC? (2)
• Mandarin ducks.
• Gorillas.
Eg of Cryptic species as a problem for MSC?
Drosophila pseudoobscura & D. persimilis.
Egs of Lack of morphological differences between species as a problem for MSC? (2)
• Willow warbler & chiff-chaff (sing different songs).
• Anopheles mosquitoes (differ in habitat).
Cryptic species?
= morphologically identical species but not the same species.
MSC attribute?
Discontinuous variation suggests different species.
Phenetic SC?
= a SC that uses as many characters as possible, equally weighted to define a species and not only one or two diagnostic features.
Phenetic SC attributes? (2)
• Recognises phenetic clusters by multivariate statistics.
• Updated numerical form of MSC.
Aim of Phenetic SC?
Objective assessment of species limits.
Differences between Morphological SC & Phenetic SC? (2)
● Morphological SC
• looks for 1 or 2 distinct characters.
• subjective assessment of species limits.
● Phenetic SC
• looks for as many characters as possible.
• objective assessment of species limits.
Tools of Phenetic SC approach? (2)
• Cluster analysis.
• Ordinance.
Cons/Problems of Phenetic SC? (3)
• Lacks a sound philosophical basis (forces you to make subjective & arbitrary decisions).
• Subjectivity.
• May get different patterns from different analyses.
Ecological/Habitat isolation?
= where species live in different habitats.
Eg of Ecological/Habitat isolation?
Gryllus pennsylvanicus & G. firmus.
Seasonal/Temporal isolation?
= where species mate at different times/seasons of the year.
Eg of Seasonal/Temporal isolation?
Sexual/Behaviour isolation in animals?
= where species are isolated if they don’t recognize a specific ritual or song.
Eg of Sexual/Behavioural isolation in animals?
Blue-footed booby males.
Sexual/Behavioural isolation in plants?
= pollinator specificity.
Eg of Sexual/Behavioural isolation in plants?
Monkey flowers
- One species is bee pollinated.
- Other species is hummingbird pollinated.
Mechanical isolation?
= where no sperm is transferred.
Eg of both Mechanical & Gametic isolation?
Purple & Red sea urchin.
Eg of Hybrid inviability?
Eg of Hybrid breakdown?
Eg of Ring species as a problem of Biological SC?
Subspecies of Ensatina salamanders in California.
Eg of Chronospecies as a problem of Biological SC?
Trilobites lineage.
Egs of Hyrids as a problem of Biological SC? (2)
• Crows.
• Cattleya orchids.
Recognition SC?
= species is a set of organisms that can recognize each other as potential mates.
Recognition SC attributes? (2)
• Developed by Hugh Patterson.
• Species share a common fertilization system (SMRS).
SMRS stands for?
Specific Mate Recognition System.
Eg of Recognition SC?
Blue footed bobbies.
Pros of Recognition SC? (2)
• SMRS can be observed, measured, identified to test hypotheses of species identities.
• More accurate representation of what courtship behaviour promotes recognition of mate.
Eg of 1st Pro of Recognition SC?
Frog sonograms (Forest & Savanna).
Eg of 2nd Pro of Recognition SC?
SMRS of Great Frigate birds (male inflates gular sac & song).
Ecological niche?
=
Ring species?
=
Chronospecies?
=
Possible egs of Phenetic SC? (2)
• Phenogram/Dendrogram of brown frogs.
• Phenogram/Dendrogram of Extinct & extant razorbirds.
Phenogram/Dendrogram?
=
Phenogram attributes? (2)
• Numbers are distance/euclidean distance.
• No inferences of evolution can be made using it.
Evolutionary SC?
= a species is a lineage evolving separately from others & with its own evolutionary role and tendencies.
Lineage?
= an ancestral descendant sequence of populations.
How is Hybridization a problem for Phylogenetic SC?
Through phylogenies not being able to trace combinations of lineages even though they can trace lineages.
Egs of Hybridization as a problem for Phylogenetic SC? (2)
• Wolves.
• Sunflowers.
Over-splitting?
= recognition of too many species.
In which populations can over-splitting impact hugely?
Fragmented populations with fixed DNA polymorphisms.
Phylogenetic SC attributes? (3)
• Requires monophyly.
• Synapomorphies diagnose a group.
• Has fewer problems dealing with asexual organisms & geographically separated forms.
Key word for Morphological SC?
Distinct & distinguishable anatomical & morphological features.
Key word for Phenetic SC?
Distinct phenetic clusters.
Key word for Biological SC?
Interbreeding natural population that are reproductively isolated.
Key word for Recognition SC?
Share a common fertilization system (SMRS).
Key word for Ecological SC?
Same ecological niche.
Key word for Evolutionary SC?
Lineage evolving separately from all lineages.
Key word for Phylogenetic SC?
Smallest biological entities that are diagnosable & monophyletic.
