Lecture 9: Species Concepts & Formations Flashcards
morphological species concept
-individuals of a single species share measurable traits
biological species concept
- species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring
- they do not breed successfully with other populations
reproductive isolation
- the existence of biological factors that impede two species from producing viable, fertile offspring
- factors could act before or after fertilization
when do prezygotic isolating mechanisms occur?
-before fertilization (b4 a zygote is born)
when do postzygotic isolating mechanisms occur?
-after fertilization(after a zygote is formed)
types of prezygotic isolating mechanisms
- habitat
- temporal
- behavioral
- mechanical
- gametic
types of postzygotic isolating mechanisms
- hybrid breakdown
- hybrid inviability
geographic isolation
- there’s a physical barrier btwn two populations(ocean, mountain range)
- results in habitat isolation
- allopatric
ecological isolation
- species live in “same” area but occupy different habitats & rarely encounter one another
- sympatric
allopatric/allopatry
-occurring in separate, non-overlaping geographical areas
sympatric/sympatry
-occupying the same or overlapping geographical
temporal isolation
-two species that reproduce in different seasons or different times of day are isolated
behavioral isolation
-courtship rituals and other behaviors unique to a species are effective barriers
what is an example of behavioral isolation?
- the blue and red footed boobies
- both bird’s dance will appear “wrong” to the other species bc they’re attracting mates of their own species
mechanical isolation
- when there’s a physical difference btwn individuals that prevents the transfer of gametes
- i.e. penis size may be to big/small
gametic isolation
-chemical cues which typically eminate from the egg can fail to attract sperm or prevent fertilization