Reproductive strategies Flashcards
Memorize (25 cards)
What are reproductive strategies
structural functional and behavioural adaptations that increase the chances of fertilization and survival of offspring
How does the success of of reproductive strategies influence their behaviour
how a species utilises energy to produce and care viable offspring
What are the 2 main types of reproduction?
K-type
R-type
What is r strategy?
More energy is utilized in producing many offspring and little energy in parental care
Many offspring die and not reach adulthood
Sufficient numbers survive to continue to continue the species regardless.
What is k-strategy?
Animals produce fewer offspring and expend enormous amounts of energy for parental care
Offspring have a better chance of surviving to adulthood
E.g lions and elephants
Look at survivorship curves
What is type 1,2,3
type l : convex curve
Type II: Straightline curve
Type III: Concave curve
Describe each type
type 1 :Young: high survivorship and low mortality
Old: Low survivorship and high mortality
E.g human, elephants, lions
Type 2: Steady survivorships at all ages
All individuals have the same chance of dying at any age
E.g. birds
Type 3: Young: low survivorship and high mortality
Old: High survivorship and low mortality
E.g frogs
What are the most important reproductive strategies?
Courtship
Ext vs Int fertilization
ovipary
ovovivipary
vivipary
amniotic egg
parental care
What is courtship?
The behavioural patterns of male and female animlas that lead to mating and ultimately offspring
What is the purpose of courtship
Both sexes ready for mating
identify mating patterns same species prevent unsuccessful mating = save energy
helps choose suitable mating partner = females chooses stronger muscular types = healthy offspring
How can courtship take place
visual stimuli
sound stimuli
chemical stimuli
physical movements
Explain visual stimuli
example = male peacock
bright striking feathers court female
female chooses male with most impressive set of feathers
egrets are also common example
nocturnal animals like fireflies specific pattern of flashes to attract mate
Int vs ext fertilization explain
Courtship successful fertilization should occur
Explain external fertilization
outside female body
occurs mostly in fish and amphbians
very little cooperative behaviour required between individuals
Internal fertilization ?
inside female body
occurs in insects and terretrial vertebrates
does not require water not limited to water enviro
fewer gametes produced = possibility of fertilization much greater
Ovi,Ovo and Vivipary?
indicate where the embryo develops and how the embryo recieves nutririon
what does the term ovipary mean?
the embryo develops in an egg outside of the females body
What is the distinction between ovipary or the two types
Oviparous aquatic animals
oviparous terrestrial animals
Explain oviparous aquatic animals
fertilization takes place externally in the water
developing embryo protected by jelly-like layer
large number gametes produced
egg with little yolk produced
oviparous terrestrial animals describe
fertilization takes place internally
developing embryo protected by a shell that protects against dehydration
fewer gametes produced by female = less energy required
production eggs with shells and large quantity of yolk lot of energy
What and describe ovovipary
internal fertilization takes place
embryo surrounded by thin membranus shell inside female body
newborn breaks through soft embryo
female produces less eggs = requires less energy
since developed internally = protected against predators and unjust temps
What and describe vivipary
internal fert
develops into an egg without shell
embryo directly connected to mother as it recieves nutrients through placenta
female produces less gametes = less energy
parental care = high large energy requirement
What is the amniotic egg
fish and amphibians need water for fert and dev of eggs
terrestrial land animals need complex protection systems on land
amniotic egg adapted to life on land
after fert embryos enclosed in egg with hard shells
egg prevents dehydration of embryo + provides nutrients water and oxygen waste products removed
describe parentak care
any behav. pattern where parents spend time and or energy on feeding and protection of offspring
more energy spent prenatal = less energy psotnatal visa versa
