BIOGEOSPHERE
Bilingual Biology and Geology
I.E.S. "J.S.Elcano (Sanlúcar Bda.)
3. Worms
This group includes several phyla: Annelids, Nematodes and Platyhelminthes.
They have in common: bilateral symmetry and soft and elongated body
without skeleton or limbs.
3.1. Platyhelminthes
They are also known as flatworms.
Some of them, such as planarian, are aquatics free-living, and others, such as taenia (tapeworm), are parasites.
They have a flat body divided into rings.
They do not have digestive or respiratory systems.
They reproduce sexually and they are hermaphrodites. This is that the same individual has both sexual organs: male and female. They have self-fertilization.
3.2. Nematodes
Some of them are free-living, aquatics or terrestrials, and others are parasites (e.g. Hookworms).
They have a cylindrical body not divided into segments or rings.
They do not have respiratory system.
They reproduce sexually and they have separate sexes. This is that there are male individuals and females individuals.
3.3. Annelids
They are also known as ringed worms.
They have a cylindrical body divided into segments called metameres. Each segment is similar and has the same organs.
There are bristles between metameres that make easy the movement.
They reproduce sexually and there are separate sexes species and hermaphrodite species. They have cross-fertilization.
The phylum is divided into three classes:
- Polychaetes (Bristle worms, rag worms
or lugworms)
They are free-living aquatic animals.
They have many bristles.
They breathe through gills and
they are filter feeders or carnivores
- Oligochaetes (Earthworms)
They are free-living terrestrial animals.
They have few bristles.
They breathe through the skin
and they are detritus feeders
- Hirudineans (Leeches)
They are parasites (bloodsuckers)
READING ACTIVITIES
After reading the text, copy and answer the following questions into your notebook:
Remember: you must make complete sentences.
3.1. Complete the table about the types of Annelids:
3.2. Listen and indicate which group of worms is described:
a. Platyhelminthes
b. Nematodes
c. Annelids
Now,
check
your
answers!
(Diccionario Ing-Esp)
(Juegos de vocabulario)
(Visual dictionary)
(Visual dictionary)
(Glosario de C. Naturales)
(Science audio-glossary)
(Science audio-glossary)
(Pronunciación)
(Enciclopedia de C. Naturales)
(Tabla periódica)
Eva Mª
López Rodríguez
Departamento
Biología y Geología
IES " J. S. Elcano"
Sanlúcar de Barrameda