REPRODUCTIVE ANIMAL STRATEGIES
INTRODUCTION
^ reproduction is the production of a new generation of organisms from an existing generation
it is life process that ensures the continued survival of the species
- What is the goal of each species?
the ultimate goal of each animal species is to produce the maximum number of surviving offspring while using the least
amount of energy
this is called reproductive effort
asexual reproduction (lower and microscopic animals) is energy efficient --> low reproductive effort -- as it involves only a
single animal
sexual reproduction (more complex vertebrates) needs a much higher energy input --> high reproductive effort -- as it
involves two animals
unique reproductive strategies have developed that will ensure maximum reproductive success in different environments
this enables the species to breed successfully and then survive to reproductive age
- The following reproductive strategies will be discussed:
(A) Courtship
(B) External vs. Internal Fertilisation
(C) Ovipary, Ovovivipary and Vivipary
(D) Amniotic Egg
(E) Precocial and Altricial Development
(F) Parental Care
, __________________________________________________________________
(A) COURTSHIP
courtship in animals is behaviour and/or signals that are designed to attract another animal for mating and breeding
- What are the different forms of courtship?
courtship strategies may be simple or complex
(1) Simple Strategies
simple strategies such as chemical (pheromones), visual (bright body parts) or auditory stimuli are used for mates to find
each other --> they can be used singly or in combination
for example:
1. females of some insect species (moths) produce species-specific pheromones that guide males towards them
2. most frogs have to return to the water for mating -- in the water, males sing (grunt, croak) to attract females --> each
species has its own song
3. male birds sing a species-specific song that attracts females --> once they meet, the male must impress and stimulate
the female sexually (often by special plumage)
(2) Complex Strategies
the more elaborate forms of courtship are unique to each species
females favour males that are:
larger
have more elaborate physical features
display more energy in courtship activity than other males
INTRODUCTION
^ reproduction is the production of a new generation of organisms from an existing generation
it is life process that ensures the continued survival of the species
- What is the goal of each species?
the ultimate goal of each animal species is to produce the maximum number of surviving offspring while using the least
amount of energy
this is called reproductive effort
asexual reproduction (lower and microscopic animals) is energy efficient --> low reproductive effort -- as it involves only a
single animal
sexual reproduction (more complex vertebrates) needs a much higher energy input --> high reproductive effort -- as it
involves two animals
unique reproductive strategies have developed that will ensure maximum reproductive success in different environments
this enables the species to breed successfully and then survive to reproductive age
- The following reproductive strategies will be discussed:
(A) Courtship
(B) External vs. Internal Fertilisation
(C) Ovipary, Ovovivipary and Vivipary
(D) Amniotic Egg
(E) Precocial and Altricial Development
(F) Parental Care
, __________________________________________________________________
(A) COURTSHIP
courtship in animals is behaviour and/or signals that are designed to attract another animal for mating and breeding
- What are the different forms of courtship?
courtship strategies may be simple or complex
(1) Simple Strategies
simple strategies such as chemical (pheromones), visual (bright body parts) or auditory stimuli are used for mates to find
each other --> they can be used singly or in combination
for example:
1. females of some insect species (moths) produce species-specific pheromones that guide males towards them
2. most frogs have to return to the water for mating -- in the water, males sing (grunt, croak) to attract females --> each
species has its own song
3. male birds sing a species-specific song that attracts females --> once they meet, the male must impress and stimulate
the female sexually (often by special plumage)
(2) Complex Strategies
the more elaborate forms of courtship are unique to each species
females favour males that are:
larger
have more elaborate physical features
display more energy in courtship activity than other males
