Robinson deck part 2 Flashcards
Define asexual reproduction and list it’s types?
Is when parent reproduces with genes from only one parent
Examples
We can see fission- split of body of parent into two different offspring. Genetically identical- see this in flatworms.
Budding is a type of asexual reproduction- is an example where adult grows on parent. Example is hydra. The parent organism grows a new organism on it which has all the same features of the parent and eventually break off.
Fragmentation- is where piece of adult organism can separate and become new organism, different than fission cause animal is not splitting into two, just a piece is coming off of it.
Parthogenesis- Is a unfertilized egg, see this in bees. Also see in vertebrates- a tailed lizard.
What are advantages of asexual reproduction?
is really useful for organisms that are reproducing in isolation- don’t need to waste energy on finding mate
Allows for rapid reproduction.
What are disadvantages of asexual reproduction?
The con is that you can’t diversify genes so disease will easily KO you
Can organisms maintain genetic diversity while being asexual? Give an example.
Whiptail lizards maintain genetic diversity by maintaining a diploid status by doubling their genetic information, allows them to asexually reproduce but still maintain genetic diversity.
What’s sexual reproduction?
offspring Have genes from two parents
Define gametogenesis
formation of male and female gametes.
Name the large gamete
Eggs are larger non motile gametes, tend to be the largest cell found in mammals.
Whats fertilization?
Fertilization is combination of egg and sperm.
Define Dioecious
means two houses, means two different sexes so two of the sexes are in separate individuals. Also called gonochoristic.
Define Monoecious
means one house- one organism houses both egg and sperm. Can have sequential hermaphrodite where animals have the ability to generate both egg and sperm at different stages. An example of this is clownfish.
What animals can self fertilize?
simultaneous hermaphrodite- they can self fertilize.
What are pros of sexual reproduction?
There’s more genetic diversity, it can be advantageous in unstable environments allows them to survive, compared to asexual wher eif one is vulnerable all are vulnerable.
What are cons of sexual reproduction?
Takes a lot of energy and resources to make these gametes and finding a mate is very costly. Can be metabolically costly, and is a lot more complex and slower than asexual reproduction.
What mechanism are in place to ensure the right sperm meets the right egg?
A lot of mechanism to ensure the right sperm meets the right egg. For example there are attractants that bring the right egg and sperm together. Only one sperm fertilizes the egg.
How does sperm fertilize and deposit info in egg
Sperm are specialized to move forward they are motile, eggs are non motile. Sperm find an egg, they have enzymes on their acrosome- a secretory vesicle, these enzyme break into the egg in order to deliver genetic information into the egg.
in animals what stages are diploid and what stages are haploid? Whats the exception to this?
In animals adult is typically diploid, gametes are the only haploid state (usually, exception is bees
What an example of external fertilization
Broadcast spawning- dispersal by releasing eggs and sperm allows sessile organisms to reproduce and the gametes are small and numerous- this is external fertilization and called broadcast spawning.
An example of this corrals- corrals release gametes at the same time and sync up in order to reproduce.
Is there external fertilization in terrestrial organisms?
No to avoid dessication need to be in aqoues environment so internal fertilization. This uses mating behaviour and competition.
Why is dispersal so important in fertilization?
Reproduction plays an important role in dispersal, want to move off spring far off.
See this in barnacles, organisms float through plankton and smells out other barnacles and goes to the bottom and then undergo metamorphosis (look this example up). So corals release gamete, bundles dissociate into egg and sperm, the sperm bind to other eggs and fertilize, float to bottom and become coral again.
The signal that makes them release gametes at once has to do with lunar cycle and light detection, still a mystery.
What are two ways stop sperm from fertilizing?
fertilizing- fast block and slow block.
Fast block- egg opens ion channel which depolarizes egg membrane and that stops second sperm from fusing with egg
In slow block- a cortical granule is released, this changes exterior properties of egg in order to stop multiple sperm for fertilizing egg. This is a permanent alteration of the exterior of the egg.
Oviparous defintion
egg bearing, these animals lay egg and thes eggs have all nourishment embryo needs.
Define vivparous
embryo is retained in mothers body, humans are this as embryo is retained in uterus.
Define ovovivparous
retain fertilized egg in body until they’re developed and egg hatch in parent
What is the first stage of early development (ontogeny)
First stage of zygote growth is cleavage and then gastrulation.
Cytoplasmic determinates in cytoplasm of egg contain all instructions for this early growth, these reticulates can contain mrna and proteins. Stored in cytoplasm in order to give first information. They play a large role in the early development of animals. All of these reticulates information comes from the mother.
What are the two ways of direct development
direct development in which young are produced nad have same body plan as mother.
Indirect development- offspring look different that parent, can hve different diets, ecology etc. We can see circumstances in which they don’t compete with eachother as they have such different body plan / makeups
Define cleavage
Cleavage is a series of mitotic divisions in which cells grow smaller and smaller as more cytoplasm isn’’t produced. At the end of vleavage we have a ball of cells called morula. In cleavage we strart seeing distinction between poles of cell.
What are the two poles in a morula
We have animals poles which usually form most of animal and are smaller cells, we have vegetal pole- these hold larger cells are yoke cells and they divide less, they might develop into the gut
What 6 mechanisms happen in gastrolation?
Gastrolation now happens after, forms ecto, meso, and endo derm. Also forms mouth/anus. Some mechanism occur during gastrulation.
Mitosis- cell dividing
Movement of cells- certain cells go to different areas.
Selective cell adhesion- some cells will stick together and others will break
Induction- a group of cells influence another group, can influence the expression of genomes.
Determination- cells are set to become something
Differentation- is when it becomes diff part of animal
What cells buckle inwards to create the archenteron in sea urchins?
vegetle cells, don’t have yolk cells
Describe how blastoceol forms in frogs
Cells from animal pole begin to invaginate to form the blastoceol, as the archenteron is formed by cells migrating through invagination of yoke cells the blastoceol becomes displaced, byt the end of this process the blastoceol is gone and only archenteron remains
