Invertebrate: Earthworm & Crayfish Compare/Contrast

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Excretory system
The system in which eliminates wastes from the body.


Worm:  The location of the excretory system is down the digestive tract.  Its structure consists of a nephridun.
Crayfish:  The excretory system of the crayfish is located at the base of the antenna; also known as the green gland.  Mainly ammonia is removed from the body of the crayfish.


Reproductive organs
An organisms organs in which contribute to sexual or asexual reproduction: eg. Egg and sperm.


Worm:  Worms are hermaphrodites, which means they contain both male and female reproductive organs.  The sperm is located in the seminal receptacle and the eggs are located in the ovaries.  When two worms come together they both act as the male and exchange sperm.

Crayfish:   Unlike the earthworm, crayfish are not hermaphrodites, and each organism is either male or female.  Their gonads are located in the dorsal of the thorax.

Skeleton and Muscles
Skeleton-The structure that holds together an invertebrate.
Muscles-The contraction of the body that results in movement.


Worm:  The skeleton of the earthworm is called a hydro static, which means it is squishy.  Their body consists of two muscles, circular and longitudinal.  As the worm contrasts, its circular muscle decreases in diameter, but at the same time it gains strength to move.  The longitudinal muscle, when contracted, shortens and widens.


Crayfish:  The skeleton of the crayfish is called an exoskeleton, which is a hard shell.  It has two kinds of muscles, extensor and flexor muscles.  Extensor muscles extend the tail, while flexor muscles bend the tail.  Both of these muscle functions able the crayfish to swim.


Habitat/Respiration
Habitat- The home of the organism.
Respiration- The way in which the organism breathes.


Worm:  The earthworm lives in places where there is moist soil and its respiration happens through its skin.
Crayfish:  A crayfishs habitat is within all freshwater environments, which means it breathes through its gills. 

A picture of the earthworm and cray fish in their natural habitat is below:

An Earthworm and Crayfish in their natural habitats:
Earthworm-In soil
Crayfish-In freshwater

Worms

Roundworms, flatworms, and segmented worms, are similar, yet so different that they are classified into three different phyla.   How can worms be different from each other when they all have the same bilateral symmetry?  Well, below I have a chart showing some examples of what makes each work unique. 



Tapeworm



Obelia Medusae

Today I had to use a microscope to locate "Obelia Medusa", a colonial marine organism.  But  being that I was unsuccessful in locating it, I decided to look up information in regards to it.

These colonial marine organisms belong to the phylum cnidaria.  You can find them in the ocean attached to either seaweed, shells, rocks or wood piles.  They kind of look like a jellyfish, they only grow about 30mm-several cm tall.

Obelia have two different ways of reproducing; Asexually, which is called polyp or Sexually, which is called medusae.  Their reproduction strategy is budding.  It starts with two medusae, then they produce an egg and a sperm.  Then throughout development, they turn into branch like organisms. 

Animal Characteristics

All animals have similarities and differences.  Their similarities consist of being heterotrphcic, ingesting food, sexually reproducing, and being primarily diploid (containing chromosomes from each parent).  The ways in which they differ are they way they develop and how they are classified in regards to a phyla tree.

Each animal reproduces basically the same way; Zygote-Blastula-Gastrula, but the way they develop is quite different depending on the organism.  All animals will either develop quickly through a process called Metamorphosis, or gradually and slow, just like humans do.  The outcome of the development differs, only because when tissues are formed they create different systems and functions within an animal.




Vertebrate: Reptile



Invertebrate: Jellyfish



As a part of the Animal Kingdom, there are two different ways to classify animals; either Invertebrate or Vertebrate.  Invertebrates do not have a presence of a backbone.  They take up the majority of phylum's on the phyla tree.  Platyhelmines, Nematoda, Annelida, Mollusca, Arthropoda, and Echinodermata, are all phylum's in which Invertebrates are.  On the other hand, Vertebrates only take up one phylum on the tree; the Chordata.  Examples of each kingdom are down above.

Animal Phyla Tree

While researching in class today I learnt:

• Snakes belong to the same phyla as us humans.
• The majority of organisms belong to either chordata or Mollusca phylum.

• The organism Peiziza Fungus, belongs to a different phyla than the ones on the tree.