<< Chapter < Page Chapter >> Page >
By the end of this section, you will be able to:
  • Describe the difference between jawless and jawed fishes
  • Explain the main characteristics of amphibians, reptiles, and birds
  • Describe the derived characteristics in birds that facilitate flight
  • Name and describe the distinguishing features of the three main groups of mammals
  • Describe the derived features that distinguish primates from other animals

Vertebrates are among the most recognizable organisms of the animal kingdom ( [link] ). More than 62,000 vertebrate species have been identified. The vertebrate species now living represent only a small portion of the vertebrates that have existed. The best-known extinct vertebrates are the dinosaurs, a unique group of reptiles, reaching sizes not seen before or since in terrestrial animals. They were the dominant terrestrial animals for 150 million years, until they died out near the end of the Cretaceous period in a mass extinction. A great deal is known about the anatomy of the dinosaurs, given the preservation of their skeletal elements in the fossil record.

Photo a shows a tiger and cub in the snow. Photo b shows a yellow frog with black spots sitting on a leaf. Photo c shows an eagle with a white breast, brown wings, and grey face.
Examples of critically endangered vertebrate species include (a) the Siberian tiger (Panthera tigris altaica ), (b) the Panamanian golden frog ( Atelopus zeteki ), and (c) the Philippine eagle ( Pithecophaga jefferyi ). (credit a: modification of work by Dave Pape; credit b: modification of work by Brian Gratwicke; credit c: modification of work by "cuatrok77"/Flickr)

Fishes

Modern fishes include an estimated 31,000 species. Fishes were the earliest vertebrates, and jawless fishes were the earliest of these. Jawless fishes—the present day hagfishes and lampreys—have a distinct cranium and complex sense organs including eyes, distinguishing them from the invertebrate chordates. The jawed fishes evolved later and are extraordinarily diverse today. Fishes are active feeders, rather than sessile, suspension feeders.

Jawless fishes

Jawless fishes are craniates (which includes all the chordate groups except the tunicates and lancelets) that represent an ancient vertebrate lineage that arose over one half-billion years ago. Some of the earliest jawless fishes were the ostracoderms (which translates as “shell-skin”). Ostracoderms, now extinct, were vertebrate fishes encased in bony armor, unlike present-day jawless fishes, which lack bone in their scales.

The clade Myxini    includes 67 species of hagfishes. Hagfishes are eel-like scavengers that live on the ocean floor and feed on dead invertebrates, other fishes, and marine mammals ( [link] a ). Hagfishes are entirely marine and are found in oceans around the world except for the polar regions. A unique feature of these animals is the slime glands beneath the skin that are able to release an extraordinary amount of mucus through surface pores. This mucus may allow the hagfish to escape from the grip of predators. Hagfish are known to enter the bodies of dead or dying organisms to devour them from the inside.

Photo a shows wormlike hagfish clustered in a muddy hole. Photo b shows leech-like sea lampreys latched onto a large fish.
(a) Pacific hagfishes are scavengers that live on the ocean floor. (b) These parasitic sea lampreys attach to their lake trout host by suction and use their rough tongues to rasp away flesh in order to feed on the trout’s blood. (credit a: modification of work by Linda Snook, NOAA/CBNMS; credit b: modification of work by USGS)

Questions & Answers

opportunity cost means the lose of other alternatives when the alternative is chosen
saad Reply
is the benefits that you loose by not selecting a certain alternative.
EDWINY
individual wants maybe unlimited, but means to satisfy them are limited there one has to forgo some alternative in order to acquire other alternative and it must according priority, that is when scale of preference set in for individuals to make choice
Rhaiymornd
hello everyone
Aliyu
Next best alternative forgiven
Shoaib
demand is the amount of goods and services that consumer is willing and able to purchase at a particular prices over given period of time
Rhaiymornd Reply
yep
Abraham
what's demand?
labi Reply
What customers want the most...
Abraham
not only what customers wants, want is just mere desire but demand is backed by purchasing power, ability and willingness
Rhaiymornd
thanks
Abraham
What's opportunity cost?
Abraham
what are the differences between demand and supply
Zakariyah Reply
who is called lender of the last resort
Divyanshu Reply
Hi
Linda
hlw
Karishma
Central bank
Majeed
hy
Karishma
Hello
Majeed
hy
Karishma
How are you
Majeed
Am gud
Linda
fine
Karishma
Am gud
Linda
hello
Chandra
Well! what's going on
Majeed
r u study in economics
Karishma
anybody there?
Chandra
r u study in economics
Karishma
the central bank
Sessay
Has completed already
Majeed
hey
neha
yes
Abigail
Yesss
Majeed
ok
Karishma
hey
Doctor
yh
Abigail
more questions
Sessay
how ar you
Doctor
split the price effect into income effect and substitution effect
Karishma
fine and u
Abigail
Hi
Godwin
hi
Hey, I am new here. Hope, discussion on Economics will clear our concepts more.
yasir
yes
Abigail
do u speak hindi or english
Karishma
how to consumer equlibrium through ic
Karishma
consumer equilibrium demand equals supply
Kenneth
the consumer is in equilibrium when the indifference curve is tangential to the budget line. or when the BL and IC intersect
Sessay
reasons indifference curve slopes downwards?
Kenneth
fine Abby any good,
Doctor
ur lost
Doctor
hey. im new year. economics teacher how we can discuss some thing interesting.
EDWINY
which one
Doctor
what do u understand the concept of poverty cycle.
EDWINY
hey
Ebong
I'm New here
Ebong
hi
ian
just new here guy's and also an Economics fresher of Kogi State University Anyigba
nelson
wxup
Ayegba
who can tell the laboratory of economic?
Amara
, Dennis Weissman Associates, LLC Laboratory Economics is the monthly business newsletter that gets behind the headlines and press releases.
Ayegba
sooo teah me what an LLC
Emmanuel
what's the topic
Adamsvictor Reply
economic systems
gracious
hello
Antonio
market
aba
hello where can I find the diagrams
Manu
Hello I am totally out ,I am not understanding why we are here. can someone help me out?
Amara
why Economic is not a pure science can someone help me out
Mohamed
because economics like science put forth a some hypotheses and then do experiments to prove them
Anwesh
but these experiments are not completely controlled
Anwesh
Hello
Comfort
hey
suraj
hi people can you help me out on "demand and supply"
Milton
Am not understanding can someone enlighten me pls
Bertilla
hi people can you help me out on "demand and supply"
Sessay
hello. if Mr.Patrick's income is #900.00 while that of Mr.Shodawe is #1300.00 if Mr.Patrick and Shodowe pay #90.00 and #130.00 as taxes,the tax system is?
Benjamin
I need the answer please
Benjamin
regressive tax system
shaikh
OK thanks
Benjamin
Isn't this called proportional tax rate because the rate stays the same - 10%? Tell me if I'm wrong
Ioan
Supply is perfectly elastic and demand increases.
kishore Reply
whose there
Waseem
show the demand curve
Hameed Reply
it slopes downward from left to right
Ama
how resources are allocated in a free economy
Charlotte Reply
explain how discriminating Monopoly increase profits
Charlotte
factors responsible for the emergence of monopoly situation
adelakun Reply
total output produced by a country over a given period of time .... can someone give me the term plz
TMM Reply
GDP
Anjorin
thaks man
TMM
Woman. 👍👍
Anjorin
gross domestic products
janet
GDP
Bertilla
GDP
Prof
GDP
Bertilla
gross domestic product
gross domestic product
GDp
Mohamed
gdp
agboola
what is recession pertaining to GDP
Prince
what is recession pertaining to GDP
Prince
what is recession
Prince
law of demand and supply
Zakariyah
All thing been equal
Temple
no i think recession is pertaining to GNP
owolabi
gross national production
Abraham
what is embago
Peter
all things being equal
Raphael
embargo restriction on trade by government of a country
owolabi
an official ban on trade or other commercial activity with a particular country.
Ayegba
Embargo.....an order by a common carrier or publ regulatory agency prohibiting or restric freight transportation
Ayegba
it's a complete band on important n export
Bertilla
who is Really Good in Mathematics. put me Through. Let Do Group Reading; am Preparing to Write Jamb this Year.
Andrew
Hi. C+I+G+x-m
Shoaib
Gdp aggregate demand are bit same
Shoaib
Dpd = c+i+g+(x-m) is aggregate demand
Shoaib
Gdp=c+i+g+(x-m) is aggregate demand
Shoaib
GDP= c+i+s+g+(x-m)
Saboor
Topic ended waiting for next topic
Shoaib
What is Terms of Trade (TOT)?
DADA
At what point a Terms of Trade can be favorable?
DADA
What is long run supply curve of a industry
Rashika Reply
enlightened
Ernest
all on board am here
Ernest Reply
am late I missed alot
Ernest
A mixed economy is the best type of an economy.Discuss
Tawanda Reply
Agreed Mixed economics is d combination of both capitalist and socialist economy, it give room for both individual and government to make decisions whereby giving room to a rapid development of d economy.
Anjorin
?
Andres
agreed
Ernest
Explain more about the Macroeconomics
Lizzy Reply
what is macroeconomic
Ekye
macro economics has to do with the of study economics at national level i.e the study of national economy as a whole. While micro is concerned with the study at individual, group or company level.
Andres
Andres explain
Ernest
ok
Ernest
what topic is capitalist economy based on
ADIBE
pls am not really understanding
Bertilla
pls can u explain more
Bertilla
in a comparison of the stages of meiosis to the stage of mitosis, which stages are unique to meiosis and which stages have the same event in botg meiosis and mitosis
Leah Reply

Get the best Algebra and trigonometry course in your pocket!





Source:  OpenStax, Concepts in biology (biology 1060 tri-c). OpenStax CNX. Jan 15, 2014 Download for free at https://legacy.cnx.org/content/col11617/1.1
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Concepts in biology (biology 1060 tri-c)' conversation and receive update notifications?

Ask