Formation of Twins

Twins
Twins are two babies born on the same day to the same mother.

There are 2 type of twins, identical and fraternal (non-identical) twins.


Click on the link below to view formation of twins.
http://www.pennmedicine.org/encyclopedia/em_DisplayAnimation.aspx?gcid=000058&ptid=17

Click on the link below to view  an interesting animation on the conception of identical twins.
http://www.pennmedicine.org/encyclopedia/em_DisplayAnimation.aspx?gcid=000033&ptid=17

Non-identical twins
Twins that are non-identical are produced from two separate eggs that are fertilised by two separate sperms. Both implant and grow in the uterus at the same time, but they are like an ordinary brother or sister; they are not genetically identical. They do not share the same placenta.






Identical twins

Identical twins form from a single fertilised egg.After fertilisation, this splits into two and an embryo forms from each of the two cells formed. Every thing about the babies is therefore identical – they have the same genes and the same patterns of gene expression; they are like two clones of the same person. They generally share the same placenta in the womb.

Non-identical twins                                            Identical twins

Brain Components

3 basic components of the brain are the cerebrum, cerebellum and medulla oblangata.

Click on the link below to view the components of the brain.
http://www.pennmedicine.org/encyclopedia/em_DisplayAnimation.aspx?gcid=000016&ptid=17

The link below is to view the brain -  with interactive tool.
http://www.pennmedicine.org/encyclopedia/em_DisplayAnimation.aspx?gcid=000015&ptid=17

Nerve Conduction

Click on the link below to view animation

http://www.pennmedicine.org/encyclopedia/em_DisplayAnimation.aspx?gcid=000089&ptid=17

Sensory Neurone

Interneurone





Motor neurone

Neurone - comparison



Phagocytosis

Click on this link to see the animation.

http://www.pennmedicine.org/encyclopedia/em_DisplayAnimation.aspx?gcid=000098&ptid=17

Endocrine System Animation

 
http://www.pennmedicine.org/encyclopedia/em_DisplayAnimation.aspx?gcid=000048&ptid=17

Homeostasis Animation

Check out the link.

http://www.pennmedicine.org/encyclopedia/em_DisplayAnimation.aspx?gcid=000070&ptid=17

                             Blood Osmotic Pressure Regulation

Blood Glucose Regulation

Body Temperature Regulation

Digestion Animation

Check out the link below.

http://www.pennmedicine.org/encyclopedia/em_DisplayAnimation.aspx?gcid=000041&ptid=17

Conception Animation

Check out the link below.

http://www.pennmedicine.org/encyclopedia/em_DisplayAnimation.aspx?gcid=000030&ptid=17

To view conception using an interactive tool, go to the link below.

http://www.pennmedicine.org/encyclopedia/em_DisplayAnimation.aspx?gcid=000031&ptid=17

Male Reproductive System - interactive

Check out the link below.

http://www.pennmedicine.org/encyclopedia/em_DisplayAnimation.aspx?gcid=000086&ptid=17

Sperm Production Animation - Spermatogenesis

http://www.pennmedicine.org/encyclopedia/em_DisplayAnimation.aspx?gcid=000120&ptid=17

Menstrual Cycle - Interactive

Check out this link.
http://www.pennmedicine.org/encyclopedia/em_DisplayAnimation.aspx?gcid=000087&ptid=17

Ovum Production Animation

Check out this link.
http://www.pennmedicine.org/encyclopedia/em_DisplayAnimation.aspx?gcid=000045&ptid=17

Reflex Response Animation

Click on the link below.
http://www.pennmedicine.org/encyclopedia/em_DisplayAnimation.aspx?gcid=000105&ptid=17

Germination Of Pollen Grain

Meiosis & Plant Fertilisation

Double Fertilisation In Flowering Plants

Baby caesarean birth C section (real life)

Cesarean Birth (C-section) Delivery & Birth

For another interesting version of C-section delivery, click on the link below.

http://www.pennmedicine.org/encyclopedia/em_DisplayAnimation.aspx?gcid=000028&ptid=17

Vaginal Childbirth

For another interesting animated version of vaginal delivery, click on the link below.

http://www.pennmedicine.org/encyclopedia/em_DisplayAnimation.aspx?gcid=000138&ptid=17

Reflex Arc

http://msjensen.cehd.umn.edu/1135/Links/Animations/Flash/0016-swf_reflex_arc.swf

Blood Glucose Regulation - Homeostasis

Urinary System - Homeostasis

Transmission of Neurotransmitters Across The Synapse

Heart Pumping

http://www.medmotion.com/html/normalheart.html

Kidney Flashplayer - Processes in Urine Production

http://www.biologymad.com/resources/kidney.swf

Prey - Predator

Interaction between 2 organisms in which one will hunt and kill the other for food.  

Predator-the hunter        Prey- the hunted        Dynamic relationship

    

                                        

                                           Couldn't resist adding this! Go Sheep Go!



It's a dynamic relationship! The poplation of prey controls the population of predator and vice versa...



 





Commensalisme



Commensalisme - a relationship between 2 species where 1 party benefits  (Comensal) whereas the other party (host) is neither harmed nor benefits,

Eg; Epiphyte (plant), epizoic (animal).

Epiphytes,  e.g.some tropical orchids use trees or branches of trees for support without harm or benefit to the tree. The epiphyte obtains more light and air in this manner for photosynthesis.

 

                                   

The remora, a sucker-fish, lives in close association with sharks or other larger fish. The dorsal fin of the sucker-fish is modified to form a sucker; it uses this to attach itself to the shark; The sucker-fish is small and does not injure (or benefit) the shark, but enjoys the shark's protection and lives on the scraps formed as the shark devours its prey



 

Barnacle – sedentary crustaceans.They use long, feathering appendages to sweep the surrounding water for small, free-floating organisms. The critical resource for barnacles is a place to stay. Barnacles attach to rocks, ships, shells, whales, and just about anywhere else they can gain a foothold.. The barnacle gains a place to live and, presumably, the other is not harmed by the presence of the barnacles. Therefore the relationship is commensalism.






Clownfishes live within the waving mass of tentacles of sea anemones; Because most fishes avoid the poisonous tentacles, the clownfishes are protected from predators. Perhaps this relationship borders on mutualism because the clownfishes actually may attract other fishes which the anemone can feed. The sea anemone's tentacles quickly paralyze and seize other fishes as prey.







Parasitism

Parasitism is a relationship between species where 1 party benefits (parasite) whereas the other party (host) loses. Ectoparasite lives on the body of the host whereas endoparasites live inside the host.

Rafflesia - Parasitic plant - Absorbs both food and water from host.

A tomato hornworm is covered with cocoons of pupating braconid wasps. The braconid wasp is considered a parasitoid of the hornworm because it causes the hornworm to die as it pupates. By the time the wasps undergo metamorphosis, all of the hosts insides have been digested, thus by the time they are ready to pupate, the caterpillar will die. While this may be detrimental to the tomato hornworm, it is considered beneficial for gardeners...as the tomato hornworm can be a signifant pest. Parasitism usually connotes a negative feeling; however as seen in this case, it can be considered beneficial.



A female mosquito blood feeding



A cluster of nematodes, the  roundworm of dogs, Toxocara canis. This parasite is  common in puppies and may be transmitted transplacentally as well as  to nursing pups in their mother's milk.



A female Nasonia vitripennis laying a clutch of eggs into the pupa of a blowfly (Phormia regina)




This shows parasitism.  The tick gets the blood it needs to survive, but the
dog is harmed by the tick transmitting disease into its blood.



An extreme example of blowfly parasitism on a 6-day-old nestling Purple Martin. This nestling's siblings had died, apparently of blowfly parasitism, forcing every maggot in the nest to be dependent on just a single host individual for their continued nourishment