Reproduction and development Part 1 Flashcards
What is sexual reproduction?
The creation of an offspring by fusion of a male gamete (sperm) and female gamete (egg) cell to form a zygote
Asexual reproduction?
The creation of offspring without the fusion of egg and sperm
Asexual reproduction exclusive to invertebrates include
Budding and fission
Budding
A form of asexual reproduction in invertebrates
- It is when new individuals arise from outgrowths of exisitng ones
Fission
The separation of a parent organism into two individuals of approximately equal size
Fragmentation
Breaking the body into pieces, some or all are well-developed into adults.
(Fragmentation must be accompanied by regeneration, and regrowth of lost body parts.)
Parthenogenesis
The development of a new individual from an unfertilized egg: This form of a sexual reproduction also occurs in some vertebrates.
Almost all eukaryotic species produce sexually
True or false
True
Sexual reproduction results in offspring of same genotypes
True or false
False
it is varied genotypes
The resulting increased variation may increase the reproductive success of parents in changing environments
True or false
True
most animals, sexual or asexual exhibit reproductive cycles related to changing seasons
True or False
True
Reproductive cycles related to changing seasons are controlled by
hormones and environmental cues.
This is because the seasonal temperature is often an important cue in reproduction.
climate change
can decrease reproductive success
Are you tired of being lonely?
Of not finding someone to sexually reproduce with?
Well… nature has the solution
Hermaphroditism!
What is Hermaphroditism?
This is when an individual has both male and female reproductive systems.
Any two hermaphrodites can mate and some can self-fertilize
Sexual reversals
In a coral reef fish, the blue-headed wrasse, a lone male defends a group of females. If the male dies, the largest female in the group transforms into a male. Within a week, this individual can begin to produce sperm instead of eggs
Fertilization
Union of sperm and eggs
External fertilization
eggs shed by the female are fertilized by sperm in the external environment
Internal fertilization
sperms are deposited in or near a female reproductive tract, and fertilization occurs within the tract
Requirements for external fertilization
- A moist habitat: This prevents gametes from drying out and allows sperm to swim to eggs
- Many aquatic invertebrates shed gametes to surrounding water: timing of release in crucial to ensure sperm and egg encounter each other
Benefit of internal fertlization
enables sperm to reach egg efficiently even when external environment is dry
In both internal and external fertilization, mating animals may use pheremones
chemicals released by one organism that can influence physiology and behavior of another individual of the same species,
