Biology: Platyhelminthes Overview
30 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which characteristic is NOT true for the phylum Platyhelminthes?

  • They have a complex respiratory system (correct)
  • They have flame cells in their excretory system
  • They can be free living or parasitic
  • All members are hermaphrodites

All organisms in the phylum Platyhelminthes have a respiratory system.

False (B)

What is the main function of flame cells in the excretory system of Platyhelminthes?

To collect excess water and excretory wastes

Platyhelminthes are _____ symmetrical organisms.

<p>bilaterally</p> Signup and view all the answers

Match the following characteristics with the correct description:

<p>Hermaphrodites = Organisms with both male and female reproductive organs Free living = Not dependent on a host for survival Flame cells = Cell structures involved in osmoregulation Parasitic = Dependent on a host for survival</p> Signup and view all the answers

What is one of the characteristics of the phylum Platyhelminthes?

<p>Acoelomate with organs (D)</p> Signup and view all the answers

All organisms within the phylum Platyhelminthes have a flattened body structure.

<p>True (A)</p> Signup and view all the answers

What type of body structure do Platyhelminthes have?

<p>Acoelomate</p> Signup and view all the answers

The body wall of organisms in the phylum Platyhelminthes consists of three ______.

<p>layers</p> Signup and view all the answers

Match the following characteristics to their descriptions related to Platyhelminthes:

<p>Acoelomate = Lacking a body cavity Flattened body = Distinctive shape of the organisms in this phylum Three tissue layers = Body wall composition Organs present = Organ systems developed within the body</p> Signup and view all the answers

What structure in the excretory system is responsible for collecting excess water and waste?

<p>Flame cells (C)</p> Signup and view all the answers

The nervous system has a ladder-like arrangement with longitudinal nerves connected transversely.

<p>True (A)</p> Signup and view all the answers

What term describes organisms that have both male and female reproductive organs?

<p>Hermaphrodites</p> Signup and view all the answers

The eyespots are located near the ________ ganglia.

<p>cerebral</p> Signup and view all the answers

Match the following systems or structures with their descriptions:

<p>Excretory tubules = Open to outside through excretory pores Cerebral ganglia = Located at the anterior end Flame cells = Collects excess water and wastes Eyespots = Detects light</p> Signup and view all the answers

What is the initial host that Miracidium invades?

<p>Lymnaea (C)</p> Signup and view all the answers

Cercaria is a larva that is capable of swimming.

<p>True (A)</p> Signup and view all the answers

What larval stage develops from Miracidium within the snail?

<p>cercaria</p> Signup and view all the answers

The larva that develops from Miracidium is called _____ and is capable of swimming.

<p>cercaria</p> Signup and view all the answers

Match the following stages of development with their characteristics:

<p>Miracidium = Invades aquatic snail Cercaria = Swimming larva with large tail</p> Signup and view all the answers

What does the larva primarily do after contacting the parasite?

<p>Starts eating liver cells (B)</p> Signup and view all the answers

The larva of the parasite spends several months eating the liver.

<p>False (B)</p> Signup and view all the answers

How long does the larva usually browse and eat the liver?

<p>A few weeks</p> Signup and view all the answers

Which class includes free-living worms found in salt water or fresh water?

<p>Class Turbellaria (B)</p> Signup and view all the answers

The larva finds the liver and starts eating _____ cells.

<p>liver</p> Signup and view all the answers

Match the following stages of the larva's behavior with their descriptions:

<p>Initial contact = Larva starts eating liver cells A few days later = Larva continues to browse After weeks = Larva consumes liver cells</p> Signup and view all the answers

All members of the Platyhelminthes phylum are parasitic.

<p>False (B)</p> Signup and view all the answers

What are the two environments where turbelleria class worms can be found?

<p>salt water or fresh water</p> Signup and view all the answers

The subkingdom of Platyhelminthes belongs to the larger classification system called __________.

<p>Metazoa</p> Signup and view all the answers

Match the following classes with their characteristics:

<p>Turbellaria = Free-living in aquatic environments Trematoda = Parasitic flatworms Cestoda = Tapeworms typically found in the intestines of hosts Platyhelminthes = Phylum of flatworms</p> Signup and view all the answers

Flashcards

Platyhelminthes Phylum

A group of invertebrates characterized by a flattened body.

Acoelomate

Animals without a body cavity.

Body wall layers

Platyhelminthes have three layers in their body wall.

Flattened body

A characteristic body shape for animals in the Platyhelminthes phylum.

Signup and view all the flashcards

Organ System

Platyhelminthes have internal organ systems.

Signup and view all the flashcards

Platyhelminthes

A phylum of flatworms, which includes both free-living and parasitic animals.

Signup and view all the flashcards

Bilateral symmetry

Having a body plan with left and right halves that are mirror images.

Signup and view all the flashcards

Flame cells

Specialized cells in Platyhelminthes that filter excess waste and water.

Signup and view all the flashcards

Excretory system

Collection and elimination of waste in Platyhelminthes.

Signup and view all the flashcards

Respiration in Platyhelminthes

Simple diffusion, since they lack a respiratory system.

Signup and view all the flashcards

Turbellaria

A class within the Platyhelminthes phylum containing free-living flatworms that inhabit freshwater or saltwater environments.

Signup and view all the flashcards

Trematoda

A class within the Platyhelminthes phylum containing parasitic flatworms known as flukes, often living in the digestive systems of their hosts.

Signup and view all the flashcards

Cestoda

A class within the Platyhelminthes phylum containing parasitic flatworms known as tapeworms, living in the intestines of their hosts.

Signup and view all the flashcards

What distinguishes Turbellaria from Trematoda and Cestoda?

Turbellaria are free-living flatworms, while Trematoda and Cestoda are parasitic flatworms.

Signup and view all the flashcards

Excretory tubules

Tiny tubes that collect waste from flame cells and carry it to excretory pores on the body surface.

Signup and view all the flashcards

Excretory pores

Openings on the body surface of flatworms through which waste products are released from the excretory tubules.

Signup and view all the flashcards

Cerebral ganglia

Two clusters of nerve cells in the head region of flatworms that act as a simple brain.

Signup and view all the flashcards

Ladder-like nervous system

The nervous system of flatworms with two main nerve cords running along the body, connected by transverse nerves, resembling a ladder.

Signup and view all the flashcards

Miracidium

A larval stage of a parasitic flatworm (fluke) that infects a specific type of aquatic snail, the Lymnaea.

Signup and view all the flashcards

Lymnaea

A genus of freshwater snails that serve as an intermediate host for certain parasitic flatworms, including flukes.

Signup and view all the flashcards

Cercaria

A larval stage of a parasitic flatworm (fluke) that develops inside the snail after the miracidium stage. It is capable of swimming with a tail.

Signup and view all the flashcards

Definitive Host

The host in which a parasite reaches sexual maturity and reproduces.

Signup and view all the flashcards

Intermediate Host

An organism that harbors a parasite during its larval development, but does not usually allow the parasite to reproduce sexually.

Signup and view all the flashcards

Liver Stage

The stage in a parasite's life cycle where it infects and consumes liver cells.

Signup and view all the flashcards

Larva's Feeding Habits

The parasite larva spends several weeks slowly feeding on liver cells.

Signup and view all the flashcards

Days After Contact

The parasite starts consuming liver cells a few days after entering the host.

Signup and view all the flashcards

Initial Contact

The first interaction between the parasite and its host.

Signup and view all the flashcards

Parasite's Life Cycle

The series of stages a parasite goes through during its lifetime.

Signup and view all the flashcards

Study Notes

Platyhelminthes

  • Phylum of acoelomate animals
  • Body wall has three layers
  • Flattened and bilaterally symmetrical
  • Hermaphrodites (except Shistosoma)
  • Free-living or parasitic
  • Respiration by simple diffusion
  • Lacking a respiratory system

Excretory System

  • Flame cells (protonephridia)
  • Collect excess water and wastes
  • Connected to excretory tubules that exit to the outside

Nervous System

  • Cephalized with a pair of cerebral ganglia at the anterior end
  • Two longitudinal nerve cords connected transversely
  • Ladder-like arrangement

Sense Organs

  • Two cup-shaped eyespots near the cerebral ganglia

Sexual Reproduction

  • Hermaphroditic (possess both male and female reproductive organs)
  • Fertilization occurs simultaneously when two worms mate
  • Eggs are laid in protective capsules

Asexual Reproduction (Regeneration)

  • Fission occurs in some species, specifically Planaria
  • Posterior part of the worm attaches to a surface
  • Body constricts behind the pharynx
  • Anterior part moves forward, splitting the worm into two
  • Each half regenerates to become a complete Planaria

Class Turbellaria

  • Free-living in fresh or saltwater
  • Resemble a plant leaf, covered by cilia
  • Possess suckers
  • Planaria species live in fresh water, hiding beneath rocks and water plants
  • Planaria possesses a dorsal surface that points upwards and a ventral surface directed downwards

Class Trematoda (Flukes)

  • Leaf-like, unsegmented bodies
  • Typically have two suckers (oral and ventral)
  • Gastrovascular cavity bifurcates into two intestinal caecae
  • All are parasitic, except for Shistosoma
  • Hermaphrodites

Fasciola gigantica Life Cycle

  • Female lays eggs in the liver of an infected human
  • Immature eggs are discharged into biliary ducts and feces
  • If eggs land in water, they develop into miracidia
  • Miracidia infect a snail (e.g., Lymnaea)
  • Develop into cercariae, which encyst on aquatic plants
  • Humans or other animals ingest the encysted metacercariae
  • Metacercariae develop into adults in the liver's bile ducts

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Platyhelminthes PDF

Description

Explore the fascinating phylum Platyhelminthes, which includes acoelomate animals like flatworms. This quiz covers their unique body structure, nervous and excretory systems, as well as their methods of reproduction. Test your knowledge on these intriguing organisms and their characteristics!

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser