Thursday 14 June 2012

Hermaphrodites: Advantages & Disadvantages

Advantages:
  1. You don't need to find a mate different to their sex. Thus, spend less energy looking for a mate.
  2. Ability to self fertilise
  3. Barely run the risk of becoming extinct.
Disadvantages:
  1. More energy is needed to maintain both reproductive systems
  2. Limited gene diversity
  3. More likely to have less viable offspring if the organism self fertilises
  4. eliminates competion for a mate allowing defected and less suitable organisms to pass on their genes.


http://mattc-thinks.blogspot.com.au/2011/06/learning-from-snails.html

Sunday 10 June 2012

Sexual & Asexual Reproduction

Sexual Reproduction:


This occurs when both male and female gametes (egg and sperm) fuze to create a zygote.
This process is required in order to adapt to new environments through genetic diversity, as those with more favourable characteristics survive and pass them on in their offspring. For example, a genetic disease would have less chance to be passed on through sexual reproduction over asexual reproduction, this is because asexual offspring are 'clones' of the parent. However, for sexual reproduction to occur, there must also be a partner or mate present.


Asexual Reproduction:


This is the process of creating identical copies or "clones" of an organism though Mitosis, Meiosis or Binary fission. Unlike sexual reproduction, asexual organisms don't require a mate. Thus one individual can replicate itself over and over. The process is shorter, which allows for more offspring faster. Artificial asexual reproduction is very beneficial in order to replicate organisms with favoured traits, such as the cuttings of a particular fruit tree that produces better/more fruit than others of its species. 




http://www.pulsarmedia.eu/r_life_in_ocean_%26_sea_wallpapers_1_starfish_40902.html
http://www.nickgarbutt.com/photo-galleries/borneo-and-se-asia/frogs

Sunday 3 June 2012

Advantages & Disadvantages of Internal and External Reproduction

Internal Reproduction.

Advantages:
  1. Increase chance gametes meet
  2. greater change of successful fertilisation
  3. More protection against outside environments and predators, and therefore a higher chance of surviving until birth.
  4. More selective of their mates 
  5. Less chance of desiccation of gametes
Disadvantages:
  1. Harder to bring both male and female into intimate contact
  2. Limited amount of offspring being produced at any given time. 
  3. Higher risk of sexually transmitted diseases being passed on.
External Reproduction.

Advantages:
  1. Results in the production of a large number of offspring
  2. Easier to find mates as the gametes released can drift (wind, water etc).
  3. More genetic variation
Disadvantages:
  1. Environmental hazards such as predators reduce the change of surviving into adulthood.
  2. Large amounts of gametes go unfertilised and wasted.
  3. Not guaranteed that sperm will come in contact with eggs
  4. Greater chance of desiccation of gametes/zygotes.


http://adarwinstudygroup.org/sexuality/internal-external-fertilization/

Thursday 31 May 2012

How the organisms in the different kingdoms reproduce

Animalia
Organisms: Mammals, amphibians, sponges, insects, starfish

Cell Type: Eukaryotic

Reproduction: Sexual reproduction and Asexual reproduction. 
Most animals reproduce sexually when half of the DNA from each of the two individual parents, in the form of a gamete. These gametes are formed via Meiosis. Some animals can reproduce asexually such as the starfish which can form identical copies of itself via fragmentation.
Plantae
Organisms: Mosses, angiosperms (flowering plants), gymnosperms, liverworts, ferns

Cell Type: Eukaryotic

Reproduction: Some species reproduce asexually by mitosis. Other species exhibit sexual reproduction
Plants can asexually reproduce via budding, fragmentation, rhizomes or stolons. Sexual reproduction in plants occurs via pollination where the pollen from the anther comes in contact with the stigma.
Fungi
Organisms: Mushrooms, yeast, molds

Cell Type: Eukaryotic



Reproduction: Asexual or sexual reproduction occur, which in fungi's case is by spore formation. These spores are created via mitosis and can grow into a multicellular organism idential to the parent.


Bacteria


Organisms: Bacteria
Cell Type: Prokariotic 

Reproduction: Binary fission. Binary fission is a form of asexual reproduction where a single parent cell produces two daughter cells identical to the parent.

Protista

Organisms: Amoebae, green algae, brown algae, diatoms, euglena, slime molds

Cell Type: Eukaryotic

Reproduction: Mostly asexual reproduction. Mitosis occurs in some species.

Simply, Asexual Reproduction occurs:

In Plants: Vegetative Formation

In Animals: Pathogenesis

In Bacteria: Binary Fission

In Fungi: Spore Formation

In Protista: Splitting