Cycle 8 (Workshop) Flashcards
What is the ecological concept of definition of species?
Populations that are adapted to specific niches in the environment
What is the morphological concept of definition of species?
Individuals of species share measurable traits that distinguish them from other species
What is the biological concept of definition of species?
Interbreeding populations that don’t reproduce with other species, all individuals in a species can successfully mate and produce viable, fertile offspring
Define:
Genetic cohesiveness
Populations of same species experience gene flow that mixes their genetic material
Define:
Genetic distinctiveness
Different species can’t exchange genetic info
What are the advantages and disadvantages of the ecological definition of species?
Explains role of environment in speciation
Unable to explain existence of same species in different environments
What are the advantages and disadvantages of the morphological definition of species?
Easy to classify physical traits to recognize species
Does not reveal much about evolutionary history
Cannot distinguish different species with similar physical characteristics
What are the advantages and disadvantages of the phylogenetic definition of species?
Applies to all groups of organisms (asexual, extinct)
Does not describe gene flow
What are the advantages and disadvantages of the biological definition of species?
Testable and describes gene flow of species
Does not apply to asexual and extinct organisms
Define:
Clinal Variation
Gradient of traits in a geographic range
Varying environment conditions favor _________ traits, thus _________ occurs within a species
Different
Evolution
Define:
Ring species
When a population migrates around geographic barrier
True or False:
The two adjacent populations of a ring population cannot interbreed
True
Are ring species considered the same species? Why
Ring species are considered same species due to shared alleles and gene pool through intermediates
List some prezygotic isolating mechanisms
Temporal isolation
Ecological isolation
Mechanical isolation
Behavioral isolation
Gamete mortality (gametic isolation)
Describe temporal isolation
Mating at different times
Describe ecological isolation
Different habitats
Describe mechanical isolation
Different reproductive structures
Describe behavioral isolation
Different mating signals (courtship displays)
Describe gamete mortality
Incompatibility between sperm and egg
List some postzygotic isolating mechnisms
Hybrid inviability
Hybrid sterility
Hybrid breakdown
Describe hybrid inviability
Conflicting genes prevents development, fertilization occurs but hybrid is frail or has early death
Describe hybrid sterility
Survives but unable to produce functional gametes
Describe hybrid breakdown
Hybrid develops and can mate with other with other hybrids and parent species
Second generation will have higher fatality, lower fertility
Long-term reproductive isolation rather than immediate
Determine the type of isolating mechanisms:
Temporal isolation
Prezygotic isolating mechanism
Determine the type of isolating mechanisms:
Ecological isolation
Prezygotic isolating mechanism
Determine the type of isolating mechanisms:
Mechanical isolation
Prezygotic isolating mechanisms
Determine the type of isolating mechanisms:
Behavioral isolation
Prezygotic isolating mechanisms
Determine the type of isolating mechanisms:
Gamete isolation
Prezygotic isolating mechanism
Determine the type of isolating mechanisms:
Hybrid inviability
Postzygotic isolating mechanisms
Determine the type of isolating mechanisms:
Hybrid sterility
Postzygotic isolating mechanisms
Determine the type of isolating mechanisms:
Hybrid Breakdown
Postzygotic isolating mechanisms
Define:
Allopatric speciation
Two populations that are geographically separated, potentially causing evolution of reproductive isolating mechanisms
Define:
Sympatric Speciation
Reproductive isolation that evolves between subgroups that arise with one population
Define:
Secondary Contact
Two previously isolated populations reunite
True or False:
Secondary contact is required for speciation to occur
False
What are the potential outcomes of secondary contact?
Reinforcement
Fusion
Describe reinforcement
Increases the rate speciation
If reproductive isolation occurs, there is speciation
When the two species are back in contact, they can’t interbreed
Describe fusion
Slows down the rate of speciation
Populations successfully interbreed, they can “fuse” back together
Gene flow can continue (remains one species)
Define:
Autopolyploid Mechanism
Chromosomes fail to separate in cell division = no reduction of number of chromosomes = gamete is a different ploidy than parent
True or False:
An offspring species occurring from autopolyploidy mechanism can interbreed with original parent species
False
True or false:
Shared similarities means shared ancestry
Not always. Shared similarities might now always reflect shared ancestry, it could be convergent evolution
What is MRCA?
Most Recent Common Ancestor
The organism from which a set of other organisms are descended
What is LUCA?
Last Universal Common Ancestor
The most recent common ancestor of all living organisms
Is LUCA the first thing to have ever lived?
No
