Biology Monerans and Protists Overview

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Questions and Answers

What defines the presence of a true coelom in animals?

A body cavity that does not allow organ suspension

A cavity that is not present during embryonic development

A body cavity formed from mesodermal tissues (correct)

A body cavity completely filled with ectodermal cells

Which of the following groups does NOT have a true coelom?

Cnidarians

Eucoelomates

Acoelomates (correct)

Pseudocoelomates

What distinguishes pseudocoelomates from acoelomates?

The presence of a spongocoel only

A fluid-filled cavity that is not entirely mesoderm-lined (correct)

Absence of any body cavity

Presence of a fully developed coelom

In which embryonic development group does the mouth form from the blastopore?

Protostomes Signup and view all the answers

What is the main characteristic of eucoelomates?

They have a true coelom lined by mesoderm Signup and view all the answers

Which type of coelom formation occurs in protostomes?

Schizocoelom Signup and view all the answers

Which of the following animals belongs to the eucoelomate group?

Annelids Signup and view all the answers

What is the function of mesenteries in eucoelomates?

To suspend body organs within the coelom Signup and view all the answers

What does the term 'Homo' in Homo sapiens represent?

The genus Signup and view all the answers

Which international code deals with the biological nomenclature for animals?

International Code of Zoological Nomenclature (ICZN) Signup and view all the answers

What is the correct format for writing scientific names?

Italicized and underlined when handwritten Signup and view all the answers

Which of the following parts of a scientific name identifies the species?

Specific epithet Signup and view all the answers

Why is binomial nomenclature important for scientific communication?

It ensures unique identification of species. Signup and view all the answers

Which of the following conventions is true regarding the genus and species names?

The genus name starts with a capital letter, the species name with a lowercase letter. Signup and view all the answers

What is primarily affected by the use of common names in species identification?

They may lead to confusion and controversy. Signup and view all the answers

In scientific names, what is typically implied by the use of Latin?

Tradition of naming Signup and view all the answers

What is one primary benefit of using scientific names for organisms?

They ensure every species has a unique name. Signup and view all the answers

What problem does binomial nomenclature aim to resolve?

The difficulty of using common names across different languages. Signup and view all the answers

According to the law of priority, what happens when multiple names are in use for a species?

The first name used is deemed the correct name. Signup and view all the answers

How does binomial nomenclature reflect the relationships among species?

Through the classification based on evolutionary lineage. Signup and view all the answers

What is a major drawback of binomial nomenclature?

It leads to an increase in synonyms. Signup and view all the answers

Which of the following statements about Monerans is true?

They lack organelles like mitochondria. Signup and view all the answers

What characteristic distinguishes Protists from Monerans?

Protists are eukaryotic organisms. Signup and view all the answers

Which of the following features is characteristic of Kingdom Protista?

Protists have membrane-bound organelles. Signup and view all the answers

Which reproductive method is commonly observed in Protista?

Asexual methods. Signup and view all the answers

What is a distinguishing feature of Chrysophytes?

They are aquatic and include organisms like diatoms. Signup and view all the answers

Which of the following organisms is known to cause sleeping sickness in humans?

Trypanosoma. Signup and view all the answers

How do protists typically exhibit locomotion?

Using cilia and flagella. Signup and view all the answers

What type of environment do most protists thrive in?

Moist terrestrial environments. Signup and view all the answers

Which of the following animals is classified as schizocoelous?

Annelida Signup and view all the answers

How does the coelom contribute to the locomotion of soft-bodied animals?

It acts as a hydrostatic skeleton. Signup and view all the answers

What is the first level in the taxonomic hierarchy?

Kingdom Signup and view all the answers

Which class of animals is characterized by having a coelom formed from the archenteron?

Enterocoelous animals Signup and view all the answers

What role do coelomocyte cells play in the coelom?

They support the immune system. Signup and view all the answers

Which of the following best defines taxonomy?

The classification of living organisms. Signup and view all the answers

Which of the following organs benefits from the coelom’s cushioning effect?

Heart Signup and view all the answers

What does the term 'haemocoel' refer to in Arthropoda and Mollusca?

A coelom filled with blood Signup and view all the answers

Study Notes

Monerans

Unicellular organisms
Contain 70S ribosomes
Naked DNA, not enclosed by a nuclear membrane
Lack organelles such as mitochondria, lysosomes, plastids, Golgi bodies, endoplasmic reticulum, centrosome
Reproduce asexually through binary fission or budding
Rigid cell wall composed of peptidoglycan
Flagellum used for locomotion
Exhibit various modes of nutrition: autotrophic, parasitic, heterotrophic, saprophytic
Examples: Archaea and Bacteria

Protists

Simple eukaryotic organisms that are not plants, animals, or fungi
Mostly unicellular, but can form colonies
Typically found in water, damp environments, or as parasites
Eukaryotic, meaning they have a membrane-enclosed nucleus
Mostly aquatic, found in soil or moist areas
Most species are unicellular, but some are multicellular like kelp, which can grow over 100 feet tall
Cells have a nucleus and membrane-bound organelles
Can be autotrophic or heterotrophic
Exhibit symbiosis, such as the relationship between kelp and sea otters
Can be parasitic, like Trypanosoma, which causes sleeping sickness in humans
Locomotion can be achieved through cilia, flagella, or pseudopodia
Reproduce asexually, sexual reproduction is rare and occurs under stress
Examples: algae, amoebas, euglena, plasmodium, slime molds

Sub-groups of Protista

Chrysophytes:
- Include golden algae (desmids) and diatoms
- Found in marine and freshwater habitats
- Often heterotrophic, depending on other organisms for food
- Have muscle cells that contract and relax body parts
- Reproduction is typically sexual, but asexual reproduction occurs in lower forms
- Zygote develops into a multicellular embryo
- Require oxygen for aerobic respiration

Coelom

A fluid-filled body cavity present between the alimentary canal and the body wall
Derived from the mesoderm during embryonic development
Lined by mesodermal epithelium cells
Provides space for organs
Functions as a shock absorber, providing flexibility to organs and cushioning internal organs
Coelomic fluid acts as a hydrostatic skeleton, aiding in locomotion of soft-bodied animals and providing body shape
Coelomocyte cells support the immune system by initiating humoral immune response and phagocytosis
Transports gases, nutrients and waste products
Enables the development and function of organs, such as the heart and uterus

Types of Coelom

Acoelomate:
- Lack a coelom
- Blastocoel is completely occupied by mesoderm
- Examples: Porifera, Coelenterata, Platyhelminthes
Pseudocoelomate:
- Lack a true coelom
- Blastocoel is partly filled by mesodermal cells
- Body cavity is lined by mesoderm only towards the body wall, not towards the gut
- Examples: Aschelminthes
Eucoelomate:
- Possess a true coelom
- Coelom is lined by mesoderm on both sides, towards the body wall and towards the gut
- Blastocoel is completely replaced by a true coelom
- Body organs are suspended in the coelom by mesenteries
- Examples: Annelida to Chordata

Formation of Coelom

Schizocoelom:
- Found in protostomes
- Coelom originates from splitting of the mesoderm
- One part attaches to ectoderm, the other surrounds endoderm
- Space between them develops into the coelom
- Blastopore forms the mouth
- Examples: Annelida, Arthropoda, Mollusca
- In Arthropoda and Mollusca, the coelom is filled with blood and known as Haemocoel
Enterocoelom:
- Found in deuterostomes
- Coelom forms from the fusion of internal outgrowths of the archenteron
- These outgrowths pinch off and fuse to form a coelom lined by mesoderm
- Examples: Echinodermata, Chordata

Taxonomic Hierarchy

A system for classifying and arranging organisms into successive levels
Hierarchy progresses from kingdom to species in decreasing order or vice versa
Kingdom is the highest rank followed by division, class, order, family, genus, and species
Each organism has a unique scientific name using binomial nomenclature

Binomial Nomenclature

A standardized system for naming organisms
Each scientific name has two parts: generic name and specific epithet
Rules of binomial nomenclature:
- Scientific names are typically in Latin
- Written in italics
- Genus name is capitalized, species name is lowercase
- Handwritten names are underlined
Importance:
- Provides a unique name for each organism, ensuring global recognition and consistency
- Avoids confusion arising from common names that can vary geographically
- Helps understand relationships between species through their scientific names
Drawbacks:
- The law of priority states that if multiple names exist, the earliest name used takes precedence
- Synonyms can arise when different names describe the same species.

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Description

Explore the fascinating world of unicellular organisms, including Monerans and Protists. This quiz covers their characteristics, nutritional modes, and reproduction methods. Test your knowledge on these essential biological classifications and their unique features.