reproductive strategies Flashcards
define Reproductive strategy
structural, functional and behavioral adaptations found in plants or animals that improve the chances of fertilization and/or increase the survival of the offspring produced.
R-strategy
Many offspring are produced
There is poor or no parental care
Many offspring die before adulthood
Eg. Frogs, fish and turtles
K-strategy
Fewer offspring are produced
Lots of parental care occurs
Many offspring survive to adulthood
Eg. humans, elephants, dolphins
Compare the K and the r strategies in a graph called a “Survivorship curve
K- Most offspring have a long lifespan and only start dying out in old age
R- Most offspring die young, very few grow old
Courtship
Courtship takes place so that a male can attract a suitable female for reproductive purposes
eg - peacock
Internal fertilization
When sperm is transferred from the males body into the female reproductive tract fertilizations happens inside the females body
-humans
External Fertilizations
When sperm and ova are released into the surrounding area then fertilizations then occurs outside the animals body
Frogs
Oviparity
occurs in animals that lay eggs, the embryo develops inside the egg -frogs
ovoviviparity
occurs when eggs are produced but kept inside the mother’s body for protection. Once embryos are fully developed, they will hatch from the egg and pass out of the mother’s body. The eggshells pass out afterwards
large snakes
vivipary
Embryo develops inside and is protected by the mother’s uterus and nourished through a placenta)
Cheetahs
Amniotic egg
Amniotic egg has a hard shell to protect the embryo and yolk to feed the growing embryo
-chicken
Parental care examples
mamamals feed their young with milk and keep their young warm with fur
