SANParks.org Forums


Previous topic | First unread post | Next topic
Page 82 of 93 [ 1393 posts ]
Go to page Previous  1 ... 79, 80, 81, 82, 83, 84, 85 ... 93  Next
Post new topic Post a reply
Print view

BIRD BIOLOGY AND BEHAVIOUR (RV)

Offline
Virtual Ranger
Joined: Wed Jan 02, 2008 4:57 pm
Posts: 3183
Location: Randburg, SA
Profile  WWW 
Wed Feb 02, 2011 6:20 pm Unread post
Rooies Plesiomorphic basically refers to an ancestral (primitive) character state with reference to another derived state. In other words an anatomical trait that is found at the base of a lineage.

Thought about it some more and agree with the answer :thumbs_up: (nice question by the way!), only there are hundreds of plesiomorphs.
Last post


Re: BIRD BIOLOGY AND BEHAVIOUR (RV)

Offline
Joined: Tue Apr 14, 2009 10:44 am
Posts: 4755
Location: On the edge of heaven
Profile  WWW 
Wed Feb 02, 2011 6:27 pm Unread post
Simply said it is the original character of a branching phyletic lineage, found in the ancestral forms.

To put it differently: It represents the most primitive state of the evolution relative to another organism.

:lol:

Correct Odessy. :thumbs_up: Only this question was directly about the Plesiomorph form of the Archaeopteryx lithographica


Re: BIRD BIOLOGY AND BEHAVIOUR (RV)

Offline
Senior Virtual Ranger
Joined: Wed Jan 10, 2007 3:44 pm
Posts: 2811
Location: Welkom
Profile 
Wed Feb 02, 2011 6:56 pm Unread post
Thank you, you clever lot :thumbs_up: But was the way of flying different from our present birds?


Re: BIRD BIOLOGY AND BEHAVIOUR (RV)

Offline
Senior Virtual Ranger
Joined: Tue Feb 16, 2010 5:51 pm
Posts: 16370
Profile 
Wed Feb 02, 2011 6:59 pm Unread post
michel367 wrote
:lol: :lol: :lol:
Nice try Odessy, but I simply want to know what the oldest and most primitive form of flying Dinosaurs is called. :whistle: :whistle:


:D :D :D The oldest and most primitive form of whatever can be called plesiomorph.

Some background info to the term:

During the 1950’s and1960’s three competing theories of classification came up:

a. Phenetic systematics (Phenetics): Organisms are classified, according to this theory, on the basis of “overall similarity”. Similarity is calculated from the presence or absence of numerous unweighted characters or character states . This method does not establish groups by inspection, but orders the lowest taxonomic units (usually species) into groups with the help of standardized procedures.
b. Cladistic systematics (Cladistics) Organisms are classified and ranked, according to this theory, exclusively on the basis of “recency of common descent”. Membership of species in taxa is recognized by the joint possession of derived (“apomorphous”) characters. Grouping and ranking are given simultaneously by the branching points.
c. Evolutionary systematics: Organisms are classified and ranked, according to this theory, on the basis of two sets of factors, 1. phylogenetic branching (“recency of common descent”, retrospectively defined), and 2. amount and nature of evolutionary change between branching points. The latter factor, in turn, depends on the evolutionary history of a respective branch, e. g., whether or not it has entered a new adaptive zone and to what extent it has experienced a major radiation.

Cladistics consists of two quite different sets of operations:
1. the reconstruction of the branching pattern of phylogeny through cladistic analysis,
2. the construction of a cladistic classification based on this branching pattern.
The most important step in the cladistic analysis is the attempt to separate characters into ancestral (plesiomorphous) and derived (apomorphous) characters.
The following terms are used to identify shared or distinct characters among groups:
• Plesiomorphy ("close form") or ancestral state, also symplesiomorphy ("shared plesiomorphy", i.e. "shared close form"), is a characteristic that is present at the base of a tree (cladogram). Since a plesiomorphy that is inherited from the common ancestor may appear anywhere in a tree, its presence provides no evidence of relationships within the tree.
• Apomorphy ("separate form") or derived state is a characteristic believed to have evolved within the tree. It can thus be used to separate one group in the tree from the rest. Within the group which shares the apomorphy it is a synapomorphy ("shared apomorphy", i.e. "shared separate form").

My conclusion: Plesiomorphic flight (if the term exists) is another term for primitive flight, but not a form of flight.


Re: BIRD BIOLOGY AND BEHAVIOUR (RV)

Offline
Senior Virtual Ranger
Joined: Wed Jan 10, 2007 3:44 pm
Posts: 2811
Location: Welkom
Profile 
Mon Feb 07, 2011 4:29 pm Unread post
The _______________ has a very unusual breeding system, called __________ in which one female mates with several males and then hands over all parental care, from incubation to chick-rearing to the males. It is called the ultimate female emancipation - and a season of hard work for the males. The chicks leave the nest within 4 hours of hatching, with a male in close attendance.


Re: BIRD BIOLOGY AND BEHAVIOUR (RV)

Offline
Joined: Wed Jun 10, 2009 8:51 am
Posts: 2159
Profile 
Mon Feb 07, 2011 6:47 pm Unread post
I think it's the African Jacana, now to check up on what the breeding system is called. :hmz:


Re: BIRD BIOLOGY AND BEHAVIOUR (RV)

Offline
Joined: Wed Jun 10, 2009 8:51 am
Posts: 2159
Profile 
Mon Feb 07, 2011 6:52 pm Unread post
Polyandrous rings a bell. :?


Re: BIRD BIOLOGY AND BEHAVIOUR (RV)

Offline
Senior Virtual Ranger
Joined: Wed Jan 10, 2007 3:44 pm
Posts: 2811
Location: Welkom
Profile 
Tue Feb 08, 2011 8:31 am Unread post
Correct Sprocky :clap: :clap:


Re: BIRD BIOLOGY AND BEHAVIOUR (RV)

Offline
Joined: Wed Jun 10, 2009 8:51 am
Posts: 2159
Profile 
Tue Feb 08, 2011 9:01 am Unread post
Thanks Rooies. :thumbs_up: Most guests are very suprised when you tell them about this. :shock:

Here is a question in the same format as your previous one...

Birds that heavily rely on their beaks for foraging have bill tips and tongues that are densely packed with receptors called ________ _______. These receptors are sensitive to both taste and touch and allow birds like Storks to locate food under water purely by touch.


Re: BIRD BIOLOGY AND BEHAVIOUR (RV)

Offline
Junior Virtual Ranger
Joined: Sun Aug 16, 2009 6:54 pm
Posts: 2142
Location: Sabie
Profile 
Wed Feb 09, 2011 5:34 am Unread post
Herbst corpuscles

[ Post made via Mobile Device ] Image


Re: BIRD BIOLOGY AND BEHAVIOUR (RV)

Offline
Joined: Wed Jun 10, 2009 8:51 am
Posts: 2159
Profile 
Wed Feb 09, 2011 7:25 am Unread post
Spot on forestgump! :thumbs_up: Take IT away!


Re: BIRD BIOLOGY AND BEHAVIOUR (RV)

Offline
Junior Virtual Ranger
Joined: Sun Aug 16, 2009 6:54 pm
Posts: 2142
Location: Sabie
Profile 
Thu Feb 10, 2011 8:01 pm Unread post
During courtship displays, these birds dive and rock from side to side ?


Re: BIRD BIOLOGY AND BEHAVIOUR (RV)

Offline
Senior Virtual Ranger
Joined: Sun Mar 08, 2009 9:37 pm
Posts: 7460
Location: Daar waar die bobbejane hul borshare kam
Profile 
Sat Feb 12, 2011 12:18 am Unread post
Cormorant?


Re: BIRD BIOLOGY AND BEHAVIOUR (RV)

Offline
Junior Virtual Ranger
Joined: Sun Aug 16, 2009 6:54 pm
Posts: 2142
Location: Sabie
Profile 
Sat Feb 12, 2011 3:04 pm Unread post
not cormorant, my bird is named because of this behaviour


Re: BIRD BIOLOGY AND BEHAVIOUR (RV)

Offline
Senior Virtual Ranger
Joined: Sun Mar 08, 2009 9:37 pm
Posts: 7460
Location: Daar waar die bobbejane hul borshare kam
Profile 
Sun Feb 13, 2011 12:11 am Unread post
Dipper? :D
Top

Post new topic  Post a reply
Go to page Previous  1 ... 79, 80, 81, 82, 83, 84, 85 ... 93  Next
Page 82 of 93 [ 1393 posts ]
Previous topic | First unread post | Next topic

Users browsing this forum: No registered users and 1 guest





Search for
Jump to