1 / 20

Crayfish Prelab

Crayfish Prelab. 2010 United streaming: crayfish 10:44 Youtube - crayfish external anatomy http://www.youtube.com/watch?v=rZ-7LF5AkGs 6.21 internal http://www.youtube.com/watch?v=rpkiNLhCBMU&feature=related 9.47 Crayfish Review

atara
Download Presentation

Crayfish Prelab

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Crayfish Prelab 2010 United streaming: crayfish 10:44 Youtube- crayfish external anatomy http://www.youtube.com/watch?v=rZ-7LF5AkGs 6.21 internal http://www.youtube.com/watch?v=rpkiNLhCBMU&feature=related 9.47 Crayfish Review http://biog-101-104.bio.cornell.edu/BioG101_104/tutorials/animals/crayfish.html Label digrams Prelab questions

  2. Taxonomic Classification • Kingdom-Animalia • Phylum-Arthropoda • Class-Crustacea • Order-Decapoda (10 feet) • Family-Astacidea • Genus-Cambarus • Species-affinis

  3. What do crayfish look like?External Anatomy (Dorsal View) • Body is divided into 2 regions: • 1.Cephalothorax (the head and carapace) • 2. Abdomen (posterior portion of body) • Label the uropods, chelipeds, antennae, and antennules

  4. External Anatomy (Ventral View) Appendages: • Crayfish appendages are biramus – branched – and jointed • 7 pairs of feeding appendages, including the mandibles and chelipeds. • Antennulescontain hearing and balancing mechanisms • Antennaecontain organs of touch, taste and smell • Swimmeretsare abdominal structures for swimming • Walking legs are thoracic structures for walking

  5. Where do they live? • In nearly all bodies of fresh water that contain lime • Why would lime be important to the crayfish? --used to harden the exoskeleton of chitin • What adaptations do crayfish show for their aquatic habitat?

  6. Respiration • They have gills as their respiratory organs. Gills take in oxygen from water and pass carbon dioxide back to the water • The gills can hold oxygen for a long time once the crayfish is out of the water What are the gills attached to? –the walking legs

  7. How do crayfish move? • Use telson, uropods, & swimmerets to swim backwards • Use walking legs (4 pairs) to crawl over the bottom • 5th pair of walking legs (crayfish are decapods) is modified as the chelipeds(pincers/claws)

  8. What do crayfish eat? • Omnivorous • fish & shrimp larvae • pond vegetation • small water insects

  9. Tracing food through the crayfish 1. Mandibles move from side to side to crush food as 2.it enters the mouth 3.Food then passes through the esophagus to the 4.cardiac stomach, where it is ground up (part of the stomach is lined with “teeth”). 5.Food then passes through the digestive glands and for digestion and temporary storage. 6.Undigested food travels through the intestine and is eliminated through the anus

  10. Excretory System: The Green Gland • The green gland is located internally just behind each antenna and right under the brain.  These structures filter fluid waste from the blood • The green glands are analogous to what human structure? _kidneys_ • Based on the crayfish’s habitat, do you think the green gland retains salt in the body of the crayfish, or excretes salt to osmoregulate?  Retain salt • Nitrogenous waste exits the body through nephridiopores into the surrounding water.

  11. Reproduction • reproduce sexually, sexes are separate, and fertilization is internal: Males – testes (white) produce sperm that exit the body through a pore at the base of the 5th pair of walking legs Females – ovaries (orange) produce eggs which are released after internal fertilization through a pore at the base of the 3rd pair of walking legs • Females usually have 10-800 eggs, which hatch in 2-20 weeks, depending on the water temperature. • Eggs are retained until mature on the swimmerets of the female • An average crayfish life span is 3-4 years

  12. Swimmerets role in Reproduction • located on the ventral side of abdomen (used for swimming and for reproduction) • Difference between males and females: • Females: crescent shaped slit; are all soft to the touch • Males: sperm duct opening (actual pore); hard to the touch

  13. Internal Male & Female structures • The male’s gonads are very difficult to find (they are located underneath the heart) • The ovaries are yellow/orange. They are located just below the carapace.

  14. Circulation of the Crawfish • Heart – located on dorsal side just below digestive glands • Opencirculatory system

  15. Nervous System • Large nerves travel from brain to ventral part of body • A _ventralnerve cord is present • Compound Eyes with more than 2,000 lenses

More Related