Compare and Contrast: Earthworm and Crayfish

Today we did a dissection on an Earthworm (Phylum:Annelida) and a Crayfish (Phylum: Arthropod). Afterwards I did a compare and contrast on their Habits, Reproduction, Movement, Nervous Systems.

Habitat:

Earthworm: Live in moist soil, they burry deep in the winters and come closer to ground and above ground when the weather is warmer.
Crayfish: Are aquatic, they live in fresh water, but are also found in salt water.

Reproduction:

Earthworm: They are hermaphrodites, so each have 2 testes, surrounded by 2 pairs of testes sacs. There are 2 or 4 pairs of seminal vesicles which produce, store, and release the sperm, via male pores. Ovaries and ovi-pores in Segment 13 release eggs from female pores. They fertilize outside of their body on the cocoon. They reproduce sexually.
Crayfish: Their way of reproduction is by pressing their undersides together, the female releases eggs, while male releases sperm. While the female passes eggs along her body through the sperm before attaching it to her swimmerets. Reproduce sexually.

Movement:

Earthworm: The earthworm moves by stretching it’s front section through the soil and then pulling its hind section up. The earthworm has two kinds of muscles that it uses to move. The circular muscles surround the worm’s body and can make the body shrink or spread out. The longitudinal muscles run along the length of the body and can shorten or lengthen the worm. The earthworm has a hydrostatic skeleton, made out of fluid.
Crayfish: A crayfish crawls with its legs, and swim really fast by turning around and flipping their tale back and forth very fast, repeatedly.

Nervous System:

Earthworm: An earthworm has no ears, eyes, or nose. They sense light and dark with small light sensitive cells found mainly on the uppers skin surface at the ends of their body. They sense vibrations and chemicals by the means of touch or chemical sensitive cells. The worm will move away from light, vibrations and dangerous chemicals.
Crayfish: The crayfish nervous system is composed of a ventral nerve cord fused with segmental ganglia.

Identifying Worms

Tapeworm:

-Phylum: Platyhelminthes

-Class: Cestoda

-Info: Flatworms: Tapeworms have a bilateral symmetry. They are semented. They  live in the digestive tract of vertebrates as adults, and in the bodies of animals when they are young.

Hookworm:

-Phylum: Nematode

-Class: Secernentea

-Info: Hookworms have a bilateral symmetry, and are segmented worms. They live in the small intestine of the host. It sucks and ingests your blood.

Earthworm:

-Phylum: Annelida

-Class: Oligochaeta

-Info: An earthworm is segmented and has a   bilateral symmetry.  These are the worms you commonly see in dirt.

Amphioxus:

-Phylum: Subphylum: Cephalochordate

-Class: Could not figure out what class it is in. 

-Info: Amphioxi are representatives of a subphylum. They are usually found buried in sand. In Asia, they are harvested commercially as food for humans and animals.

Roundworm:

-Phylum: Nematode

-Class: Arachnida

-Info: Roundworms have  bilateral symmetry, with a pseudoceolom. They are not segmented. They are covered by a tough outer layer called a cuticle. The cuticle does not grow; it must be shed as the worm grows. After shedding, a new cuticle is made.

Sea Urchin Embryology: 3 different stages.

The development of a sea urchin is a representation of animal development and similar stages occur in in all animals from the hydra. When the sea urchin embryo divides, the cell becomes smaller, until it is in the blastula stage (1st). By the time they hatch from their eggs they can barely be seen when magnified. A sea urchin comes from the Phylum: Echinodermata, and is on the left side of the my tree diagram, it is a Deuterostome. 
The first stage we looked at was a unfertilized egg, second was a fertilized egg, and third was gastrulation. 

We quite obviously skipped a few steps in our lab, so if it were in the proper order it would go like this:

1-Unfertilized Egg

2-Fertilized Egg

3-Two celled stage

4-Each cell divides

5-Four celled stage

6-Eight celled stage

7-Blastula, hollow ball

8-Gastrulation, 2 layers

The photos here a the cell stages we looked at today in class.

Phylum Sorting

Today I learned about:
-Over the past few days I thought "Anthopoda" was and Invertebrate Phylum. But Anthropoda actually refers to humans, what I was meant to be calling it was "Arthopoda" which refers to invertebrates like spiders, hermit crabs etc.
-I learned that sea horses and sting rays (just to name a few) are Chordates, which is the same as humans. Although humans are vertebrates, whereas sting rays and sea horses are invertebrates.
-One more thing I found interesting in today's lesson was that Octopi and Bivalves are in the same Phylum; *Mollusca. A bivalve looks like one of those regular shells you might find on the beach.

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Intro to Animals Unit

In my Biology 11 class we have just started studying Animals. We started covering Animal Distinctions,Characteristics, the Two Groups;Invertebrates and Vertebrates, Symmetry, and the Body Cavities of bilateral animals.

Animal Distinctions:

-Gradual Development

-Metamorphosis

-They have a variety of cells with specialized functions (highly-specialized)

Characteristics:

-Heterotroph: "An organism that cannot manufacture its own food and instead obtains its food and energy by taking in organic substances, usually plant or animal matter. All animals, protozoans, fungi, and most bacteria are heterotrophs."

-Ingest Food

-Primarily Diploid: "A cell or an organism consisting of two sets of chromosomes, usually, one set from the mother and another set from the father."

-Sexual Reproduction

-Zygote~Blastula~Gastrula

Two Groups:

-Invertebrates

-Vertebrates, Phylum:Chordata

Invertebrates:

-Without backbones

-eg. Phyla, Porifera, Cnideria, Platyhelminthes, Nematoda, Annelida, Mollusca, Anthropoda, and Echinodermata.

Vertebrates:

-With backbones

-eg. Fishes (cartilaginous, bony), amphibians, reptiles, aves (birds), and mammals.

Symmetry:

-Radial Symmetry: "Symmetrical arrangement of parts of an organism around a single main axis, so that the organism can be divided into similar halves by any plane that contains the main axis. The body plans of echinoderms, ctenophores, cnidarians, and many sponges and sea anemones show radial symmetry."

-Bilateral Symmetry: "Symmetrical arrangement of an organism or part of an organism along a central axis, so that the organism or part can be divided into two equal halves. Bilateral symmetry is a characteristic of animals that are capable of moving freely through their environments."

Body Cavities-Bilateral Animals:

-Ectoderm: outside

-Endoderm: inside

-Mesoderm: in-between

*Coelom: in the mesoderm

*Pseudocoelomates: sort of have coelom

*Acoelomates: no body cavities


Quotes from http://www.thefreedictionary.com/