Class Notes (834,881)
Canada (508,787)
BIOA01H3 (687)
Lecture

evo lec 6.docx

3 Pages
81 Views
Unlock Document

Department
Biological Sciences
Course
BIOA01H3
Professor
Mark Fitzpatrick
Semester
Winter

Description
Speciation and Reproductive isolation mechanisms Species: group of individuals who are able to mate amongst themselves to make healthy offsprings Exceptions: Horses and donkeys mate to make mules -Hooded crow and carrion crows can make hybrids, but are geographically separated Reproductive Isolation Mechanisms: factors that does not allow for successful reproduction Pre zygotic Barriers: prior to when a zygote is formed -Prevention of Mating: doesn’t allow for having sex -Behavioral Isolation: each species may use different signals or behaviors to attract mates. Sometimes they don’t work or are incompatible. -Birds and frogs sing a song -Temporal Isolation: mating at the wrong time cannot allow them to mate even though they could be in the same habitat. -Flower mating seasons -Ecological/Habitat Isolation: species occupy different habitats within the same area wherethey’re separated and cannot mate -Northwest Garter snakes prefer meadows while common garter snakes are in water all the time Prevention of fertilizing: doesn’t allow for fertilization -Mechanical Isolation: Different species don’t mate because their genitals aren’t compatible for mating -Genitals of damsel flies are different from other flies and can only mate with their own species -Gametic Isolation: If gametes from different species do not meet, barriers preventing sperm and eggs from forming a zygote. -Sperm might not survive in female, or molecular markers on eggs signal sperms that this isn’t the right egg, and will ignore it Post Zygotic Barriers: doesn’t allow for successful growth of the hybrid (refers to offspring from mating 2 species) -Reduction of Hybrid viability: Fetus forms after fertilization, but followed by spontaneous abortion due to genetic incompatibility. -lethal alleles terminates the process -chromosome number mismatches, first stage of mitosis terminates -Reduced zygotic barriers: Hybrid offspring could become sterile. Problem because chromosome number during mating because parental chromosomes differ from other species or parental species. -Donkey and horse’s hybrid is sterile -Hybrid Breakdown: F1 hybrids may work, but F2 hybrids are often always ste
More Less

Related notes for BIOA01H3

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit