Analogy and Homology Blog Post

Blog Post Guidelines (60 pts total):

Due Thursday of Week 3 by 11:59 pm (two responses to two other posts due Friday, 11:59)

For your blog post, you will select two sets of traits, one set of homologs and one set of analogs, to evaluate and analyze. You cannot use the example of eagle, penguin and bat wings from above.

Your case study must include the following:

1. For your homologus traits provide the following information (25 pts):

a. Briefly describe the two different species that possess the homologus trait. (5 pts)

In New Zealand Kiwi is a peculiar little bird that lives on the ground like a scavenging mammal.  Its plumage is more like fur than feathers and it snoops along the ground, sniffing for worms and bugs to eat.  The Kiwi still has wings, but they are now useless appendages, scarcely seen under the foliage.  The Kiwi (top photo) can smell and detect organisms below the surface because its nostrils are at the end of its beak.  The New Zealand Kiwi, is considered the most un-birdlike bird of all the birds.  Scientists found that the ancestor of the Kiwi could fly.

The wandering albatross (Diomedea exulans), an oceanic bird, has the greatest wingspan of all birds and lives in the southern oceans (see bottom photo).  This bird is at home on top of the water or ruling the skies.  It is can fly on long continuous trips with ease.

b. Describe the homologus trait of each species, focusing on the differences in structure and function of the trait. Why do these homologus traits exhibit differences between the two species? Make sure your explanation is clear and complete. (10 pts)

Kiwi Traits:

Feathers – hair-like

Bi-pedal – walks on two legs

Wings – unusable nubs

Beak – long beak, nostrils at the end for better smelling ability

Claws/Talons – normal for the most part

Albatross Traits:

Feathers – long, distinct, designed to glide           on air, light weight

Bipedal – walks on two legs

Wings – used for flight

Beak – long

Claws/Talons – normal

The differences between these common traits are due to natural selection & genetic mutations.  New Zealand has few bird predators and flight exerts a lot of energy.  It makes sense to dispose of it altogether if there is no longer any reason for flight.  Long wings can be a hindrance to a bird that dwells primarily on the ground like the Kiwi.  Since the best food sources are just beneath the soil, Kiwis adapted their beaks to have nostrils at the end.

The Albatross flourishes over the oceans and so its beak adapted to hold fish, and its wings are built for long distance, high endurance flights.

c. Who was (generally, not specifically) the common ancestor of these two species and how do you know that ancestor possessed this homologus trait? (5 pts)

The Kiwi is similar to the Tinamous of South America.  The Tinamous is pudgy, not the best flyer, but non-the less can fly.  They are adept runners like the Kiwi.  Even before this there was the dinosaur/ bird (Archaeopteryx), which is thought to be the ancestor of modern day birds.  This bird has been found to have feathers, wings, and had limited flight.

d. Provide an image of each species in this comparison. (5 pts)

Photo Source: http://www.nhnz.tv/factsnz, http://grandnationaltrailer.com/lightbar-grumman-albatross-jet-ski/

2. For your analogous traits provide the following information (25 pts):

a. Briefly describe the two different species that possess the analogous trait. (5 pts)

The Fossa (top) is a descendent of the Mongoose.   The Fossa is from Madagascar and typically fills the role a cat would on those islands, hunting prey from the trees.  It grows up to six feet long and weighing less than 26 pounds.

(Cryptoprocta ferox)
Order: Carnivora
Family: Euplerida

The Puma (bottom) is from the genus felida (Puma concolor), .  It is also known as a mountain lion.  It is the largest of the small cat family.  It can run very fast and pounce on prey from above.  Until its habitat was disturbed, pumas were spread out the most compared to any other American terrestrial animal.

Order: Carnivora
Family: Felidae

b. Describe the analogous trait of each species, focusing on the similarities in structure and function of the trait. Clearly explain why these analogous traits exhibit similarities between the two species. (10 pts)

Fossa Traits:

Large paws

Sharp retractable claws

Large cat-like teeth

Long tail for maneuvering and balance

Solitary

Dwells on ground and in trees

Short haired brownish coats

The largest carnivore of Madagascar

Puma Traits:

Ambush hunters and live in treed mountainous or tropical areas

Sharp retractable claws

Large paws

Large teeth

Long tail for maneuvering and balance

Solitary

Dwells on ground and in trees

Short haired brownish coats

c. All pairs of organisms share some common ancestor if you go back far enough in time. Did the common ancestor of these two species possess this analogous trait? Why or why not? (5 pts)

The most likely ancestor of the Fossa and Puma would have been a weasel type mammal thought to exist some thirty million years ago apart of the Proailurus genus.  In what is now modern-day France there was the species called P-lemanensis.  This animal was small, had short legs, a long torso, and cat-like qualities.  From there cats may have developed from an animal apart of the Pseudaelurus genus.  These animals were thought to be the Miocene ancestors of the saber-tooth and what we know as modern day cats. It possessed many of the modern day traits.

d. Provide an image of each species in this comparison. (5 pts)

Photo Sources: http://www.usmessageboard.com/science-and-technology/175997-all-non-africans-part-neanderthal-genetics-confirm-6.html

http://www.fantom-xp.com/en_20__Big_cats_-_Puma.html

Sources:

1.

http://www.nhnz.tv/factsnz

http://www.nzherald.co.nz/environment/news/article.cfm?c_id=39&objectid=10530788

http://www.earthlife.net/birds/tinamiformes.html

http://www.livescience.com/2846-theory-flightless-birds-shot.html

http://www.wildanimalsonline.com/birds/wanderingalbatross.php

http://animals.about.com/cs/birds/p/albatross.htm

http://www.innerbird.com/ancestors_feathered_dinos/bird_ancestors.html

2.

http://www.sandiegozoo.org/animalbytes/t-puma.html

http://animals.nationalgeographic.com/animals/mammals/fossa/

http://www.britannica.com/EBchecked/topic/483346/puma

http://animaldiversity.ummz.umich.edu/site/accounts/information/Puma_concolor.html

http://www.edgeofexistence.org/mammals/species_info.php?id=43

http://www.desertusa.com/may96/du_mlion.html

http://www.carnivoraforum.com/index.cgi?board=mustelids&action=print&thread=2991

http://www.messybeast.com/cat-prehistory.htm