CHAPTER 1 : Living Organisms and Classification

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Questions and Answers

What does respiration in living cells primarily involve?

  • Taking in nutrients and water
  • Breaking down nutrient molecules to release energy (correct)
  • Releasing waste products into the environment
  • Increasing the size of the organism

What is a defining characteristic of growth in living organisms?

  • The ability to reproduce offspring
  • A permanent increase in size and dry mass (correct)
  • Movement from one place to another
  • A temporary increase in size

Which of the following best describes excretion?

  • Sensing changes in the environment
  • Taking in materials for energy and growth
  • Removing waste products and excess substances from the body (correct)
  • Conducting chemical reactions to utilize energy

Sensitivity in living organisms refers to their ability to:

<p>Detect and respond to environmental changes (C)</p> Signup and view all the answers

What process is responsible for producing more of the same kind of organism?

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

Which statement accurately describes nutrition?

<p>It includes both organic substances and minerals for growth and development (B)</p> Signup and view all the answers

What is meant by dry mass in biology?

<p>The mass of an organism after removing its water content (B)</p> Signup and view all the answers

What characteristic is NOT associated with reptiles?

<p>They lay soft eggs in a jelly-like coat. (B)</p> Signup and view all the answers

Which feature is unique to amphibians compared to the other classes mentioned?

<p>They have external ear drums. (A)</p> Signup and view all the answers

Which of the following statements about mammals is true?

<p>Mammals possess mammary glands that secrete milk. (C)</p> Signup and view all the answers

How do birds modify their body for flight?

<p>By having beaks modified according to their diet. (B)</p> Signup and view all the answers

Which characteristic helps amphibians during their aquatic life stage?

<p>External gills for breathing. (C)</p> Signup and view all the answers

What is the primary purpose of classification in biology?

<p>To facilitate the study and identification of living organisms. (D)</p> Signup and view all the answers

Which taxonomic rank is the largest among the following?

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

In the binomial naming system, how is the genus represented?

<p>In italics with a capital letter. (C)</p> Signup and view all the answers

Which of the following correctly defines 'species'?

<p>A group of organisms capable of breeding and producing fertile offspring. (D)</p> Signup and view all the answers

What is the correct sequence of the taxonomic hierarchy from largest to smallest?

<p>Kingdom, Phylum, Class, Order, Family, Genus, Species. (C)</p> Signup and view all the answers

What differentiates cladistics from traditional classification systems?

<p>It focuses on DNA structure and evolutionary relationships. (B)</p> Signup and view all the answers

What does the term 'morphology' refer to in biological classification?

<p>External features of organisms. (C)</p> Signup and view all the answers

What characteristic is NOT a feature of the classification system?

<p>It encourages habitat preservation. (B)</p> Signup and view all the answers

Which of these correctly identifies a class within the taxonomic hierarchy?

<p>Phylum Mammalia. (C)</p> Signup and view all the answers

What is the primary focus of classification systems in biology?

<p>To reflect evolutionary relationships among organisms (B)</p> Signup and view all the answers

Which two studies traditionally form the basis of biological classification?

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

Which of the following structures is NOT commonly found in the cells of all living organisms?

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

What structures are found in most fungi that differentiate them from bacteria?

<p>Cell walls made of chitin (D)</p> Signup and view all the answers

What do ribosomes in living organisms primarily do?

<p>Synthesise proteins (D)</p> Signup and view all the answers

Which of the following organisms belong to the Kingdom Protoctista?

<p>Amoeba (D)</p> Signup and view all the answers

Which kingdom includes organisms with no nucleus?

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

Which of the following is NOT a characteristic of prokaryotic organisms?

<p>Contain a nucleus (B)</p> Signup and view all the answers

How do yeast reproduce under favorable conditions?

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

How do prokaryotic ribosomes compare to those in other kingdoms?

<p>They are smaller (A)</p> Signup and view all the answers

What is the principal component of the body structure of fungi?

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

What type of cells do fungi have?

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

What is the main component of the cell wall in prokaryotic organisms?

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

What is the primary method of reproduction for most fungi?

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

What type of DNA structure do prokaryotic organisms typically have?

<p>Circular and not associated with proteins (D)</p> Signup and view all the answers

What is one of the primary protective features some types of prokaryotic organisms may have?

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

Which of the following structures contains many nuclei in the cytoplasm?

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

In what way do protozoa differ from multicellular organisms in the Kingdom Protoctista?

<p>Protozoa are unicellular. (A)</p> Signup and view all the answers

What characteristic is shared by both fungi and bacteria?

<p>Presence of a cell wall (C)</p> Signup and view all the answers

What component may some members of the Kingdom Protoctista contain for photosynthesis?

<p>Chlorophyll (D)</p> Signup and view all the answers

Flashcards

Respiration

Chemical reactions that break down nutrient molecules in living cells to release energy for metabolism.

Nutrition

Taking in organic substances and minerals for growth, tissue repair, development, and energy production.

Excretion

Removal of toxic materials, waste products of metabolism, and excess substances.

Metabolism

The sum of all chemical reactions in cells including respiration.

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Growth

A permanent increase in size and dry mass due to an increase in cell number or cell size.

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Reproduction

The processes that produce more of the same kind of organism.

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Movement

An action by an organism or part of an organism causing a change of position or place.

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Sensitivity

The ability to detect and respond to changes in the internal or external environment.

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Anatomy

The science focused on understanding an organism's internal structure.

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Morphology

The study of external shapes and features of an organism.

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Species

A group of living organisms that share common features and can interbreed to produce fertile offspring.

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Genus

A group of closely related species that share many characteristics.

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Kingdom

The largest taxonomic rank, grouping organisms with shared fundamental characteristics.

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Binomial Nomenclature

The scientific system of assigning two-part names to species.

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Cladistics

A method of classifying organisms based on their evolutionary relationships, primarily through DNA analysis.

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Classification

Arranging organisms into groups based on shared features, providing a hierarchical structure for understanding life's diversity.

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Drying to Constant Weight

The process of removing water from a sample by repeated heating and weighing until the mass remains constant.

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Eukaryotic organisms

Organisms with a true nucleus and other membrane-bound organelles.

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Prokaryotic organisms

Organisms without a nucleus and other membrane-bound organelles.

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Cell

The main building block of life, found in all living organisms.

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Cytoplasm

A jelly-like substance that fills the cell and contains numerous organelles.

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Cell membrane

A thin membrane that surrounds the cell, controlling what enters and exits.

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DNA

The genetic material of a cell, containing the instructions for building and maintaining the organism.

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Ribosomes

Tiny organelles responsible for protein synthesis.

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Plasmids

Small, circular pieces of DNA found in some prokaryotes.

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Reptiles

A class of land-dwelling vertebrates characterized by dry, scaly skin, eggs with a tough shell, and the ability to regulate their body temperature.

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Reptile scales

The outer layer of skin in reptiles, made of scales that help reduce water loss.

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Reptile eggs

Reptiles don't need to be near water to reproduce; their eggs have a protective shell.

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Reptile temperature regulation

Reptiles can adjust their body temperature to some extent, unlike cold-blooded animals that rely solely on the environment.

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Amphibian characteristics

Amphibians are vertebrates with moist skin, external ear drums, and nostrils at the top of the head.

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What is a prokaryote?

A single-celled organism that lacks a nucleus and other membrane-bound organelles.

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What is a eukaryote?

A multi-cellular organism composed of eukaryotic cells, meaning they have a nucleus and other membrane-bound organelles.

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What is the Kingdom Protoctista?

This kingdom includes a diverse group of organisms that are mainly unicellular, but also includes multicellular organisms like seaweeds. They are often found in aquatic environments and can be photosynthetic or heterotrophic.

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What is the Kingdom Fungi?

This kingdom consists of organisms that are heterotrophic, meaning they obtain nutrients from other organisms. These organisms are typically multicellular and have cell walls made of chitin. Examples include mushrooms, molds, and yeasts.

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What are hyphae?

The long, thread-like structures that make up the body of a fungus.

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What is a mycelium?

The mass of interwoven hyphae that forms the body of a fungus.

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How do Fungi Reproduce?

A process by which fungi reproduce, typically involving the release of spores.

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What is chitin?

Chitin is a tough, durable polysaccharide commonly found in the cell walls of fungi, exoskeletons of insects, and some other organisms. It is a structural material.

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What is budding?

This type of reproduction involves the formation of a bud that grows out of the parent cell, eventually detaching to form a new organism. This is a common mode of reproduction in yeast.

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What is a saprophyte?

Fungi obtain nutrients by breaking down organic matter from dead organisms.

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Study Notes

Characteristics of Living Organisms

  • Living organisms exhibit several key characteristics
  • These characteristics are essential for defining life
  • The key characteristics include:
    • Movement: A change in position or location by an organism or part of an organism
    • Respiration: Chemical reactions occurring in cells releasing energy for metabolism
    • Sensitivity: Detection and response to changes in the internal or external environment
    • Growth: A permanent increase in size or dry mass
    • Reproduction: Processes creating more of the same kind of organism
    • Excretion: Removal of waste products of metabolism and excess substances
    • Nutrition: Intake of materials for energy, growth, and development

Classification of Living Organisms

  • Classification involves sorting living organisms based on shared features (morphology and anatomy).
  • Morphology refers to external features
  • Anatomy refers to internal structure
  • There are different levels of classification
    • Kingdom (largest category)
      • Example: Animal Kingdom
    • Phylum
      • Example: Arthropoda
    • Class
      • Example: Insects
    • Order
    • Family
    • Genus
    • Species (smallest and most specific category)
  • Examples of species: Humans, cats, and dogs

Importance of Classification

  • Facilitates the study of living organisms
  • Aids in identification of organisms
  • Aims to reflect evolutionary relationships

The Binomial System

  • A system for naming organisms using two names
  • The first name represents genus (capitalized)
  • The second name represents species (lowercase)
  • Scientific names are written in Latin and are italicized or underlined.
  • For example, the scientific name for humans is Homo sapiens.

Prokaryotes

  • Organisms lacking a nucleus and membrane-bound organelles
  • Examples include bacteria.
  • Bacteria can have several shapes:
    • Spiral
    • Spherical
    • Rod shaped

The Five Kingdoms

  • A classification system in biology
  • The kingdoms include:
    • Prokaryotes/Monera
    • Protoctista
    • Fungi
    • Plants
    • Animals

Prokaryotic Organisms

  • Characteristics
    • Lack a nucleus and other membrane-bound organelles
    • Contain DNA in a circular form
    • Often covered with a sticky protective layer
    • Some have flagella used for movement
    • Some contain chlorophyll for photosynthesis
    • Often reproduce by binary fission

Kingdom Protoctista

  • Unicellular or multicellular organisms
  • Often aquatic
  • Some contain chloroplasts
  • Examples: Amoeba and paramecium

Kingdom Fungi

  • Multicellular eukaryotes
  • Cell walls mainly composed of chitin
  • Most are not motile
  • Reproduce through spores
  • Exist as moulds or mushrooms or yeasts
  • Obtain food by decomposing organic material
  • Some are parasitic or symbiotic.

Kingdom Plantae

  • Multicellular eukaryotes
  • Contain chlorophyll for photosynthesis
  • Produce flowers and fruits
  • Often reproduce by seeds (flowering plants)
  • Most reproduce via spores (ferns)
  • Examples: Ferns and flowering plants

Kingdom Animalia

  • Multicellular eukaryotes
  • Lack cell walls
  • Nutrition
    • Obtain nutrients by consuming other organisms
    • Can be
      • Herbivores, carnivores, omnivores, detritivores
  • Usually motile (move from place to place)

Phylum Arthropoda

  • A group of invertebrates with segmented bodies
  • Examples
    • Insects
    • Crustaceans
    • Arachnids
    • Myriapods

Class Insects

  • Have three body regions (head, thorax, abdomen)
  • Three pairs of jointed legs
  • One pair of antennae
  • Most have compound eyes
  • Many have wings

Class Arachnids

  • Two body regions (cephalothorax and abdomen)
  • Four pairs of jointed legs
  • No antennae or wings
  • Usually have simple eyes

Class Crustaceans

  • Have an exoskeleton, Two body segments (cephalothorax and abdomen)
  • One or two pairs of antennae
  • Varying number of legs
  • Usually aquatic, breathe through gills
  • Examples include crabs, lobsters, and shrimps.

Class Myriapods

  • Have a long segmented body
  • Many pairs of legs
  • Typically live on land

Viruses

  • Considered an intermediate form between living and non-living organisms
  • Difficult to classify
  • Lack cytoplasm and organelles
  • Replication only occurs within host cells
  • Consist of a nucleic acid core and protein coat
  • Cannot reproduce outside a host organism
  • Often infectious agents

Dry Mass

  • The mass of an organism after removing all its water content
  • Useful for studying plant growth, and other similar processes.

Paper 4 Questions

  • Questions about classification systems, morphology, anatomy, features in cells, and organisms

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Chapter 1 Extended Characteristics of Living Organisms PDF

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