Class Notes (836,147)
Canada (509,656)
Biology (Sci) (2,472)
BIOL 111 (283)
Lecture 12

Lecture 12 - Nematods and Annelids.docx

7 Pages
54 Views
Unlock Document

Department
Biology (Sci)
Course
BIOL 111
Professor
Suzanne Gray
Semester
Fall

Description
• continuous operation October 13 th intestine stomach phNEMATODES AND ANNELIDS anus mouth Development of the digestive tract enables:  Specialization of gut regions  Sequential food processing  Continuous operation How does a complete digestive tract develop? second opening digor tractavity first opening (blastopore) Two ways to develop a diststive tract: 1. Protostomes (1 mouth):  Blastopore  mouth 3  New opening ndnus 2. Deuterostomes (2 is mouth)  Blastopore  anus  New opening  mouth  Example: Humans Protostome animals: Ecdysozoans: have an external covering secreted by epidermis that must be shed in order to grow Lophotrocozoans: have one of the following characteristics (some animals may have lost it secondarily or that it is only present in some groups)  Lophophore: ciliated feeding/gas exchange structure  Trocophore: a ciliated free-living larval form (on the top and a band around the middle Difference in body cavities:  There are three different body plans with respect to body cavities  Greek root of coelom = cavity 1. Acoelomate: a. No coelom b. Solid except digestive space 2. Pseudocoelomate: a. False coelom b. Mesoderm lines the outside of coelom c. Example: Nematoda October 13 th NEMATODES AND ANNELIDS 3. Coelomate: a. Mesoderm lines the entire cavity as a “peritoneum” (lining derived from mesoderm) b. Example: Humans; peritoneum attaches are organs and keeps them in place 2 Ways to Make a Coelom: Coelem isolates the gut from body movement, provides a hydrostatic skeleton that can assist in support and movement, storage reservoir for gametes and waste, provides space for organ development. 1. Schizocoely: a. Splitting within the mesoderm b. Protosomes 2. Enterocoely: a. Mesoderm forms pockets from gut b. Deuterostomes Phylum Nematoda:  Roundworms  Ecdysozoan (molting animal)  Thick, flexible cuticle; allows diffusion of gases, must live in moist habitat  Pseudocoelomates  Longitudinal muscles; move by thrashing  Tapered posterior end  Blunt anterior end Phylum Nematoda • bilaterally symmmetrcall • triploblastic • fluid-filled body No respiratory or caviy -hydrostatic cicuatoy ystem skeleton • complete digestive tract Nematoda Diversity:  ~25,000 species (est. 1,000,000)  Terrestrial (moist soil) or aquatic  Free-living (scavengers, pNematoda diversityitic  Extremely abundant  Poster Child: C. elegans- “white rat” of geneticists and developmental biologists • ~25,000 species (est. 1,000,000)  Dr. Heikimi and col•eat rrestrial (moist soil) or aquaticmutated, resulted in nematodes to live ~6x their normal life span • rfee-living (scavengers, predatory) or parasitic  Worms used energy m•reextremely abundanted & swam at a slower pace • C. elegans - “whe attofgenetcstss and developmental biologists efficiently and fed & swam at a slower pace October 13th NEMATODES AND ANNELIDS Nematodes are important part of food web of soil Most nematodes are scavengers and predators but some are parasitic  Infect protists, plants & animals
More Less

Related notes for BIOL 111

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit