Reproductive Strategies in Vertebrates Flashcards
reproductive
strategy
structural, functional and behavioural adaptations that improve
the chances of fertilisation and the survival of offspring
external
fertilisation
fertilisation that takes place outside the female’s body, usually in
water
internal
fertilisation
fertilisation that occurs inside the female’s body where the male
has deposited its sperm
ovipary
eggs are laid; the embryo develops outside the mother’s body
ovovivipary
young develop from eggs fertilised internally and retained within
the mother’s body after fertilisation until they hatch
vivipary
the young develop inside the uterus of mother after eggs are
fertilised internally; young are nourished through the placenta
amniotic egg
the embryo inside the egg is protected by a hard shell; the egg
consists of many extra-embryonic membranes that serve
different functions
extraembryonic
membranes
membranes that surround the developing embryo inside the
amniotic egg or uterus.
amnion
produces amniotic fluid which cushions embryo and protects it
from mechanical injury, temperature changes, dehydration
allantois
collects the embryo’s nitrogenous waste and assists in the
exchange of gases
chorion
allows for gaseous exchange in the amniotic egg and forms the
placenta in mammals
yolk sac
contains the food reserves for the developing embryo
precocial
development
when hatchlings are well developed as they hatch, able to move
and feed themselves, with eyes open – limited parental care
altricial
development
when hatchlings are underdeveloped as they hatch, unable to
move or feed or fend for themselves – young require more
parental care
(AL-tricial: A Lot of parental care )
parental care
includes the building of nests, protection, teaching of young and
feeding – the care, or lack thereof, directly influences the
survival of the young
what are the 2 main types of reproductive strategies
1- r- strategy (little parental care)
2- k - strategy (lots parental care)
describe r- strategy (3)
1- expend more energy in producing many offsprings
2- less time + energy spent on parental care
3- most offsprings die before adulthood
hint: “r” for reproducing, more energy spent spent on reproducing
descr k- strategy (3)
1- expend less energy in producing many offsprings
2- more time + energy spent on parental care
3- most offsprings survive to adulthood
name the 5 reproductive strategies
1- ext vs int fertilisation
2- ovipary, ovovivpary and vivipary
3- amniotic egg
4- precocial and altricial dev
5- parental care
fertilisation
when a sperm cell + egg cell fuses to form a zygote
name 4 characteristics of ext fertilisation
1- req water (prev desiccation)
2- gametes (sperm + egg cells) released into water
3- many gametes released
4- high mortality rates among young due to lack of protection. Ova (egg) easily dedicated and predated on
name 2 species that are externally fertilised
1- fish
2- amphibia
name 4 characteristics of internal fertilisation
1- dont require water
2- sperm cells released into females body
3- fewer gametes released
4- lower mortality rates among young = protection provided by the mothers body or leathery shell
name 3 species that are internally fertilized
1- reptiles
2- birds
3- mammals
name 4 characteristics of ovipary
ovi = egg
FeDeNT (fertilisation, dev of embryo, nutrition, type of egg)
1- fertilisation: ext (aquatic) or int (terrestrial)
2- dev of embryo (where): ext females body
3- nutrition: yolk
- little produced (aquatic) = less energy
- lots produced (terrestrial) = more energy
4- type of egg: jelly - like
name 4 characteristics of ovovivpary
ovi: egg
vivi: live
FeDeNT (fertilisation, dev of embryo, nutrition, type of egg)
1- fertilisation : int
2- dev of embryo: inside females body
3- nutrition: yolk present in egg
- young independent
4- type of egg: calcareous or leathery
name 4 characteristics of vivipary
vivi: live
FeDeNT (fertilisation, dev of embryo, nutrition, type of egg)
1- fertilisation: int
2- dev of embryo: inside females body
3- nutrition: young recieve nutrition from mothers body via placenta
4- type of egg: none
name 7 things found inside and amniotic egg
1- amnion (membrane)
2- allantois (membrane)
3- chorion (membrane)
4- yolk sac
5- hardened calcareous/ leathery shell
6- albumen (food reserve)
7- dev embryo