lecture 10 and 11

lecture 10 and 11 - SEXUAL REPRODUCTION CONTINUED: Weeks 10...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
MALE MAMMALS HAVE PENIS CAN BE QUITE COMPLEX IN SHAPE OPOSSUM HAS A FORKED PENIS, MALE CATS HAVE SPINES ON THEIRS . WHY? INTROMITTENT ORGAN CAN ALSO HAVE A SECONDARY ROLE OF STIMULATION BACULUM = PENIS BONE. A SUPPORT FOR THE PENIS FOUND IN BATS, SHREWS, MOLES, CARNIVORES, MOST PRIMATES, ie WALRUS SEXUAL SELECTION = A SUBSET OF NATURAL SELECTION SEXUAL SELECTION DEALS ONLY WITH CHARACTERISTICS THAT OFFER OWNER AN ADVANTAGE IN PASSING ON ITS GENETIC MATERIAL SEXUAL SELECTION IS MOSTLY DRIVEN BY FEMALE CHOICE BUT NOT EXCLUSIVELY: ALSO MALE-MALE AGGRESSION, FEMALE-FEMALE AGGRESSION, MALE CHOICE CHALLENGE IS FIND THE OPPOSITE SEX OF THE RIGHT SPECIES TO MATE WITH SO. .. HOW DO ANIMALS MEET? (1) MEET BY CHANCE: BARNACLES ON SEASHORE ROCKS, SHIPS, OR, EVEN ON WHALES. LONG PENIS WANDERS AROUND ROCKS AND STICKS IN OTHER BARNACLE. BARNACLES DOUBLE CHANCES OF PRODUCING YOUNG BARNACLES BY BEING HERMAPHRODITES (CONTAIN BOTH SEXES) HERMAPHRODITISM IS ALSO FOUND IN CLAMS, SLUGS, SNAILS, EARTHWORMS. THESE ARE SEDENTARY OR SLOW - MOVING ANIMALS – DOUBLES THEIR CHANCES OF PRODUCING YOUNG ADVERTISING FOR A MATE (A) ADVERTISE VISUALLY COLOUR – MALE BIRDS USUALLY MORE COLOURFUL EXAMPLES: HOUSE FINCHES – FEMALES CHOOSE MALES MORE BRIGHTLY COLOURED (1) BRIGHT COLOURS MORE APPARENT TO PREDATOR, COULD BE TELLING FEMALE MALE IS SURVIVOR ( 2) BRIGHTEST COLOUR MIGHT REFLECT GOOD HEALTH (LOW PARASITES) (3) BRIGHT COLOURS MIGHT REFLECT SUPERIOR FORAGING SKILLS PHALAROPES FEMALES MORE BRIGHTLY COLOURED THAN MALES The sexual dimorphism and contribution to parenting are reversed in the 3 phalarope species. Females are larger and more brightly coloured than males. The females pursue males, compete for nesting territory, and will aggressively defend their nests and chosen mates. Once the females lay their eggs, they begin their southward migration, leaving the males to incubate the eggs and care for the young (B) OFTEN COLOUR SHOWN TO BEST ADVANTAGE IN SPECIAL DISPLAY BIRD DISPLAYS: OFTEN HIGHLY RITUALIZED AND EXAGGERATED MOVEMENTS HEAD DISPLAYS : BUFFLEHEAD = HEAD BOBBING
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
HOODED MERGANSER : CREST RAISING WING DISPLAYS: RED-WINGED BLACKBIRD – EPAULETTE DISPLAY TAIL DISPLAYS: GROUSE : RUFFED AND SPRUCE GROUSE WALK THE WALK AND SAIL THE TAIL ! SOME DISPLAYS ARE DONE IN THE AIR = AERIAL DISPLAYS: HUMMINGBIRDS : ARCS = PENDULUM DISPLAY EBONY JEWELWINGS COMMUNAL DISPLAY SITES , USUALLY GROUPS OF MALES DISPLAYING (A) FIREFLY LIGHT DISPLAYS (B) SWARMS OF MALES: MAYFLIES, ALSO FLIES, MIDGES, MOSQUITOES (C) LEKS : SITES WHERE COMMUNAL DISPLAYS OF BIRDS TAKE PLACE. A gathering for the purpose of competitive mating display EXAMPLE: WILD TURKEYS , SAGE GROUSE IN LEKKING GROUSE, CHEST SAC COLOUR IS IMPORTANT = REFLECTS HEALTH. SAGE GROUSE
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 08/13/2008 for the course BIOL 1902 taught by Professor Runtz during the Winter '08 term at Carleton CA.

Page1 / 8

lecture 10 and 11 - SEXUAL REPRODUCTION CONTINUED: Weeks 10...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online