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Earthworms

Howard Tang

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Quote

“The plough is one of the most ancient and most valuable of man’s inventions; but long before it existed, the land was in fact regularly ploughed, and still continues to be thus ploughed, by earthworms. It may be doubted whether there are many other animals which have played so important a part in the history of the world. As have these lowly organized creatures.” -Charles Darwin

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Scientific Name: Lumbricidae (Family)

Kingdom: Animalia - eukaryotic, heterotrophic, lack cell walls, motile

Phylum: Annelida - segmented worms

Class: Oligochaeta - spacious coelom used as a hydroskeleton

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Overview

  • Found in soil feeding on both live and dead matter
  • Breathes through its skin
  • Hermaphrodites: have both male and female sex organs
  • Helps in the nitrogen cycle
  • Regenerate themselves

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Anatomy

  • Cylindrical tube divided into metamerisms separated by septa
  • Thin cuticle over skin on each segment
  • Dorsal pores excrete fluids that moisten and protect the worm and helps it to breathe
  • Each segment (except mouth & anus) contains (4+ pairs) setae to help with movement
  • Clitellum produces eggs
  • Digestive tract runs through the middle and is flanked by blood vessels
  • Periproct contains the anus

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https://en.wikipedia.org/wiki/File:Annelid_redone_w_white_background.svg

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Types of Worms

  1. Leaf-litter
    • Lives on the Earth’s surface
    • Non-burrowing
    • Decompose leaves and litter
  2. Topsoil/ Subsoil
    • Lives near the surface
    • Burrows and casts within the soil
    • Feeds on soil
  3. Burrowing
    • Constructs permanent vertical burrows
    • Uses burrows to reach the surface to obtain food (such as leaves)

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Benefits

  1. Biological
    • Converts organic matter to humus
  2. Chemical
    • Converts small soil particles into more “plant-friendly” material
    • 5x nitrogen, 7x phosphates, 11x potassium
  3. Physical
    • “Ploughs the land”
    • Creates aeration and drainage
  4. Human
    • Increases pastoral productivity by 25-30%
  5. Other
    • Provides food for other species

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Interesting Facts

  • There are around 6000 species of earthworms in the world
  • Baby worms emerge from their “cocoons” fully formed
  • Worms can grow up to 10 feet
  • Of the 180 or more species of earthworms in US/ Canada,

~60 are invasive species

http://cdn0.wideopenspaces.com/wp-content/uploads/2014/07/17.jpg

http://b50ym1n8ryw31pmkr4671ui1c64.wpengine.netdna-cdn.com/wp-content/blogs.dir/11/files/2014/02/blog-earthworm-egg-cases-nrcs142p2_050324.jpg

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Regeneration

Worms can regenerate their bodies,

but the ability to do so:

  • varies across different species.
  • depends on the amount of damage done

https://media.giphy.com/media/V8iyReg7i7tmM/giphy.gif

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Works Cited

Alpert, Matt. Giant Earthworm. Digital image. WideOpenSpaces. N.p., 20 Dec. 2015. Web. 24 Apr. 2017.

Beans, Laura. "10 Interesting Facts About Earthworms." EcoWatch. N.p., 09 Jan. 2017. Web. 23 Apr.

2017.

"Composting." Worm Anatomy & Physiology - Compost-ology. EulessTX, n.d. Web. 24 Apr. 2017.

Elegancecoral. Nitrogen Cycle. Digital image. PhotoBucket. N.p., n.d. Web. 24 Apr. 2017.

Lloyd, Christopher, and Andy Forshaw. What on Earth Evolved?: 100 Species That Changed the World.

New York: Bloomsbury, 2009. Print.

Schroeder, K. D. Annelid Redzone. Digital image. Wikimedia Commons. N.p., 9 June 2014. Web. 24 Apr.

2017.

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Works Cited

Silvestro, Roger Di. Earthworm Eggs. Digital image. Garden Habitats. N.p., 26 Feb. 2014. Web. 24 Apr.

2017.

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