Reproduction & Environment Flashcards
Induced ovulation
Allows females to release mature egg cells during or shortly after copulation
It depends on stimuli generated by actual act of copulation
Spontaneous ovulators
Ovulation results from processes endogenous to the female – independent from mating (human, dogs & rats)
Many processes must occur PRIOR to fusion of egg and sperm to ensure they meet and new zygote has chance to succeed
monitoring of enviro cues change of location development of repro organs resource acquisition male & female attraction spawning of copulation
AFTER conception, many processes must occur for zygote to develop into an independent offspring
zygote development offspring provisioning early epigenetic tagging confrontation of enviro stresses evasion of predators
Mate association
aspects physiologists study
Potential mates need to find each other and communicate sexual readiness
Female blue crabs can mate only when they have just molted
Male and female crabs travel together for days prior to mating so the male will be present when the female molts
Control of the annual cycle of reproduction
aspects physiologists study
Most animal species reproduce at particular time of the year (seasonal changes)
Rocky Mountain Elk –antler growth strongly controlled by photoperiod
Functions of reproductive organs and cells
aspects physiologists study
how eggs are made, how erection occur, how sperm cells sustained and transformed after being discharged from male, how milk synthesized
Delivery resources to offspring by parents
aspects physiologists study
Parents transfer large quantities of resources to their offspring by prenatal process (e.g. synthesizing eggs yolk) or postnatal process (bringing food to young, nursing them with milk)
Physiology and environment relations of the young
aspects physiologists study
offspring face challenges because they are small, immature and live in environment different from those of their parents. Physiologists study adaptation of these young at each stage of development
Temperature and photoperiod are used as cues
In spring of the year: rising environment temp →↑ plants growth → ↑ food supply
Photoperiod = number of hours of daylight/per 24 hr
1) Using internal circannual clocks
adjust internal circannual clocks to synchronize with annual events of outside world
2) Most mammals adjust their reproductive physiology
correspond to the immediate prevailing photoperiod in their environment
Mice use long photoperiod as indicator for spring & summer and remain state of reproductive readiness as long as the photoperiod is long
Melatonin hormone secreted by pineal gland at night participate in control of reproduction
Latitude trends in reproduction in white-footed mice, deer mice
Length of reproductive season varies dramatically with latitude: Short at high latitudes (spring and summer are short); Longer at mid-latitudes
Bronson (2009) studied effect of climate changes on seasonal reproduction of mammals at latitude
Small, short-lived rodents of the world may adapt rather easily
Longer-lived mammals whose reproduction is regulated by photoperiod may not do so well
Animals live in distinctive habitats use distinctive cues for reproduction
Desert animals use rainfall as principal cue for reproduction
Animals living along the seacoast use tidal cues as principal cue for reproduction
