12.1 What Is a Species Flashcards
What is a species?
A group whose members have the greatest resemblance
Are different species always very different looking?
No
What is a biological species?
A group of individuals that, in nature, can interbreed and produce fertile offspring but cannot with members of other species
Can different, but similar, biological species mate and have offspring?
No
What is a genealogical species?
defines species as smallest group of reproductively compatible individuals descended from a single common ancestor
What is a morphological species?
A group of individuals with some reliable physical characteristics that distinguish them from all other species
Which definition for species essentially separates different races of similar organisms?
?
Can different, but similar, genealogical species mate and have offspring?
Yes but it will be infertile
Which definition for species is most applicable to fossilized remains?
Morphological species
How do new species develop?
- Isolation of gene pools of populations
- Evolutionary changes in gene pools of populations
- Evolution of reproductive isolation between populations
What are 5 basic pre-fertilization barriers?
Spatial Behavioral Mechanical Temporal Gamete incompatibility
What are two basic post-fertilization barriers?
Hybrid inviability
Hybrid sterility
What is an example of special reproductive isolation?
Species are separated by distance
What is an example of behavioral reproductive isolation?
Differences in mating behavior may interfere with reproduction
What is an example of mechanical reproductive isolation?
Sexual organs are incompatible
What is an example of temporal reproductive isolation?
Difference in timing of reproduction
What is an example of gamete compatibility reproductive isolation?
Eggs and sperm of different species are unable to fuse
What is hybrid inviability?
A zygote is unable to develop because genetic instructions are incomplete
Ex: sheep crosses with goat and produces an embryo but it does early in development
What is hybrid infertility?
Product of interspecies cross unable to produce
Ex: mule
What is a population?
A subgroup of species that is somewhat independent from other groups
What is gene flow?
A spread on an allele throughout a species gene pool
How can gene flow be prevented?
Through post and pre-fertilization
