New User Special Price Expires in

Let's log you in.

Sign in with Facebook


Don't have a StudySoup account? Create one here!


Create a StudySoup account

Be part of our community, it's free to join!

Sign up with Facebook


Create your account
By creating an account you agree to StudySoup's terms and conditions and privacy policy

Already have a StudySoup account? Login here

Lecture 1 Notes

by: Jacob Decker

Lecture 1 Notes ZOL 328

Jacob Decker
GPA 3.71
View Full Document for 0 Karma

View Full Document


Unlock These Notes for FREE

Enter your email below and we will instantly email you these Notes for Compar Anat & Bio Verteb (W)

(Limited time offer)

Unlock Notes

Already have a StudySoup account? Login here

Unlock FREE Class Notes

Enter your email below to receive Compar Anat & Bio Verteb (W) notes

Everyone needs better class notes. Enter your email and we will send you notes for this class for free.

Unlock FREE notes

About this Document

Notes for the first lecture.
Compar Anat & Bio Verteb (W)
P. Rasmussen
Class Notes
notes, Lecture, 1




Popular in Compar Anat & Bio Verteb (W)

Popular in Microbiology

This 8 page Class Notes was uploaded by Jacob Decker on Saturday January 23, 2016. The Class Notes belongs to ZOL 328 at Michigan State University taught by P. Rasmussen in Winter 2016. Since its upload, it has received 156 views. For similar materials see Compar Anat & Bio Verteb (W) in Microbiology at Michigan State University.


Reviews for Lecture 1 Notes


Report this Material


What is Karma?


Karma is the currency of StudySoup.

You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!

Date Created: 01/23/16
Lecture 1  What is comparative anatomy, and why is it important? o The comparative study of vertebrate structures  All vertebrates share a common origin o Most structures are homologous  Shared because of common origin  Same muscles in men and mice o Comparative anatomy allows us to determine relationships  Allows reconstruction of evolutionary history  Fundamental to understanding of function  Fundamental to finding cures and treatments  Can extrapolate findings from studies on mice to humans  Example: What is the functional significance of different tail shapes of sharks and bony fishes? o Sharks have heterocercal tails (upper lobe lengthened)  Correlated with lack of swim bladder  Movement of extended upper lob provides lift, keeps from sinking o Bony fishes (teleosts) usually have homocercal tails (both lobes equal length)  Most have swim bladder  Adjustable air-filled sac that provides neutral buoyancy  It’s not just about learning the names of bones and muscles! o Comparative anatomy brings together many related fields  Evolution  Paleontology  Systematics  Genetics  Developmental biology  Physiology  Physics  Grand Design? Historical Context o Humans have long observed and admired the complexity, elegance, and precision of the human body and those of other species  Many noted resemblances between species  Most thought divine intervention the cause  No alternative explanation known o Linnaeus (1707-1778)  Inventor of hierarchical binomial system still used today to classify and name all organisms  Came up with his system to reflect God’s grand plan for creation  Thought species were recently created and immutable o Some others postulated vague evolutionary ideas  E.g., Erasmus Darwin (1731-1802)  “Would if be too bold to imagine, that all warm- blooded animals have arisen from one living filament…?”  Gave no mechanisms of evolution  Lamarck’s (R)evolutionary Ideas o 1744-1829 o Maintained that species changed through time o His other ideas misleading but influential:  Simplest species arose through spontaneous generation  Progressive change from simple (low) to most complex and perfect (us; high)  Changes arose to fit need  Use and disuse  Acquired characteristics  Cuvier and Irreducible design o 1769-1832 o Father of Paleontology o Demonstrated the fact of extinction o Showed that the different parts of an organism are tightly coupled to make the functional whole  Only certain possible combinations that must harmonize  Thought that precluded evolution because any change would be fatal  Charles Darwin o 1809-1882 o Born into wealthy family  Expected to become a doctor, then a vicar  More interested in natural history o Ended up as captain’s companion/ship’s naturalist on the HMS Beagle, 1831-1836  His specimens and observations of similar but distinct species on different islands of the Galapagos and elsewhere led him o postulate organic change  “It is like confessing a murder.”  Needed a mechanism  Needed proof  Darwin’s Big Idea o Spent the next 20 years amassing evidence  Read Malthus on human populations in 1838  Realized that populations breed to numbers larger than the environment can support  Meant that favorable changes would be more likely to survive, unfavorable to perish o “Here, then, I had at last got a theory by which to work.”  Noted this is exactly what farmers had been doing for thousands of years  Artificial selection vs. natural selection  Alfred Russell Wallace o 1823-1913 o Working-class, trained as surveyor  Went to Brazil to collect insects and birds  Lost his collections and notes in fire on return o In Malay Archipelago, noted striking patterns of endemism, relationships, and faunal breaks between islands o In Ternate (northern Moluccas, Indonesia), it came to him in a fever:  “Then I at once saw, that the ever present variability of all living things would furnish the material from which… the fittest alone would continue the race… survival of the fittest.”  Wrote a message, sent it to Darwin  The advent of the Theory of Evolution by Natural Selection o Darwin’s receipt of Wallace’s message was a shock  Both men’s papers read jointly at an 1858 meeting of the Linnaean Society  Darwin quickly published his “short” Origin of Species  Instant bestseller  Darwin’s work was backed by many years of research, unlike Wallace’s ideas o Darwin avoided public controversy o His colleague, Thomas Huxley, championed his ideas  “How stupid of me not to have thought of that”  “I am sharpening up my claws and beak in readiness” o Huxley a famous comparative anatomist  Richard Owen o 1804-1892 o Coined name “Dinosauria” o Initially believed in immutability of species o Came to believe in evolutionary process but not Darwin’s o Recognized underlying similarities  Promoted idea of “archetypes”  Underlying body plan from which all parts arose  All vertebrates share the same archetype  Differences forced on underlying plan by functional need  What is natural selection? o Species produce more offspring than can survive o Offspring vary, some variation is heritable o Heritable variations that best suit an organism to its environment will tend to be favored and be passed on to offspring, leading to change in successive generations  What, then, is evolution? o Descent with modification  Darwin only began using the term “evolution” in his 6 edition of the Origin of Species o Change in allele (gene variant) frequencies between gene pools of parental and offspring generations  Microevolution  May lead to e.g. smaller size, paler fur, larger canines, etc.  Gradual, small changes  Macroevolution is the sum of many small changes over long periods  Can result in:  Duplicate or missing structures  Repurposing of existing structures  Divergence  Brief history of pre-chordate life o C. 3.5 BYA (billion years ago): first prokaryotes o C. 2.3 BYA: oxygen revolution o C. 2 BYA: first eukaryotes o C. 1 BYA: first multicellular organisms o C. 800 MYA (million years ago): Cambrian explosion, first chordates and appearance of most animal phyla  Origin of Chordates o Chordata just one of about 30 animal phyla  Fourth in terms of numbers of described species with <44,0000  Anthropoda much more specious  >>1 million  The three living groups (subphyla) of chordates o Cephalochordata: lancelets/amphioxus o Urochordata: tunicates and scalps o Vertebrates: fishes, amphibians, reptiles, mammals  Includes us and our other favorite species  What IS a chordate? o Largest group of bilaterian coelomate deuterostomes  Bilateria: bilaterally symmetrical  Coelom: fluid-filled internal body cavity completely surrounded by mesoderm  Deuterostome: pattern of development  Radial cleavage  Coelom from outpouching of gut  Anus from blastopore  Skeleton from mesoderm  Most invertebrates protostomes  Protostome vs. deuterostome patterns of development o Cleavage: cell division before growth o Schizocoelic vs enterocoelic o Gastrulation: when round hollow ball of cells start to invaginate, blastopore is first indentation  Ebryonic tissue layers o No true tissues in sponges Profera o Two tissue layers, ectoderm and endoderm, in corals and their relatives, Radiata o Three tissue layers (triptoblasts), including mesoderm, in other animals, Bilateria  Chordate characteristics o Present at least at some life stage:  Notochord  Dorsal hollow nerve cord  Pharyngeal slits  Endostyle or thyroid gland  Postanal tail  Notochord o Flexible rod that resists shortening o Elastic rod that can be flexed laterally  Allows lateral flexion  Contraction os muscles sweeps tail to side and against surrounding water  On muscle relaxation, spring notochord straightens body  Cannot be telescoped  Prevents collapse of body  Cooperative action of outer fibrous sheath and fluid core o Hydrostatic organ  Dorsal Hollow Nerve Cord o Derived from ectoderm  Forms by invagination  Surface ectoderm thickens into neural plate  Neural plate folds and invaginates into tube  Pharyngeal slits o Evolutionarily, first found in hemichordates  Found in all chordates at some life stage o Pharynx is part of digestive tract immediate posterior to mouth  Walls of pharynx push out into series of pharyngeal puches  Pierce or nearly pierce pharyngeal walls o Gill slits in aquatic chordates for respiration  Non-respiratory in embryos o Likely evolved for suspension feeding  Initially with cilia for water movement  Only works well for small organisms  Endostyle or thyroid gland o Endostyle: glandular groove in floor of pharynx o Filter-feeding o Thyroid gland: endocrine gland producing two major hormones o Arises from floor of pharynx  Post-anal tail o Tail that ends posterior to anus  Extension of locomotor apparatus  Segmented musculature and notochord  Has important role in swimming and in other forms of locomotion and balance  Sometimes external tail lost but still present internally and embryologically o Anus terminal (at extreme posterior) in non-chordates


Buy Material

Are you sure you want to buy this material for

0 Karma

Buy Material

BOOM! Enjoy Your Free Notes!

We've added these Notes to your profile, click here to view them now.


You're already Subscribed!

Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'

Why people love StudySoup

Jim McGreen Ohio University

"Knowing I can count on the Elite Notetaker in my class allows me to focus on what the professor is saying instead of just scribbling notes the whole time and falling behind."

Kyle Maynard Purdue

"When you're taking detailed notes and trying to help everyone else out in the class, it really helps you learn and understand the I made $280 on my first study guide!"

Steve Martinelli UC Los Angeles

"There's no way I would have passed my Organic Chemistry class this semester without the notes and study guides I got from StudySoup."


"Their 'Elite Notetakers' are making over $1,200/month in sales by creating high quality content that helps their classmates in a time of need."

Become an Elite Notetaker and start selling your notes online!

Refund Policy


All subscriptions to StudySoup are paid in full at the time of subscribing. To change your credit card information or to cancel your subscription, go to "Edit Settings". All credit card information will be available there. If you should decide to cancel your subscription, it will continue to be valid until the next payment period, as all payments for the current period were made in advance. For special circumstances, please email


StudySoup has more than 1 million course-specific study resources to help students study smarter. If you’re having trouble finding what you’re looking for, our customer support team can help you find what you need! Feel free to contact them here:

Recurring Subscriptions: If you have canceled your recurring subscription on the day of renewal and have not downloaded any documents, you may request a refund by submitting an email to

Satisfaction Guarantee: If you’re not satisfied with your subscription, you can contact us for further help. Contact must be made within 3 business days of your subscription purchase and your refund request will be subject for review.

Please Note: Refunds can never be provided more than 30 days after the initial purchase date regardless of your activity on the site.