Chapter 1🔬 Characteristics of Living Organisms
🔬 Characteristics of Living Organisms
All organisms show seven characteristics of life:
Movement – Ability to change position or place.
Respiration – Chemical reactions that break down nutrients to release energy.
Sensitivity – Ability to detect and respond to changes in the environment.
Growth – A permanent increase in size and dry mass (mass after removing all water).
Reproduction – The process of producing offspring.
Excretion – Removal of waste products.
Nutrition – Taking in materials for energy and growth.
🧬 Key Biological Terms
Metabolism: All chemical reactions in living organisms.
Dry mass: The mass of an organism after water is removed.
Organic substances: Molecules containing carbon, made by living organisms.
Chlorophyll: Green pigment that absorbs light energy for photosynthesis.
Cellulose: A carbohydrate forming plant cell walls.
🧑🔬 Classification & Kingdoms
🔑 Key Concepts
Kingdom: Major groups in which organisms are classified.
Common ancestor: A species from the past that gave rise to others.
Binomial system: Scientific naming system using genus (capitalized) + species (lowercase), e.g., Homo sapiens.
Genus: A group of related species with similar features.
Species: Organisms that can reproduce to form fertile offspring.
Dichotomous key: A tool using pairs of statements to identify organisms.
🌱 Kingdoms Overview
1.
Animal Kingdom
No cell walls or chloroplasts.
Vertebrates and arthropods are subgroups.
🐾 Mammals
Pinna: Outer ear flap.
Placenta: Connects fetus and mother for nutrient exchange.
Mammary glands: Produce milk.
Diaphragm: Muscle aiding breathing.
🦴 Vertebrates
Have backbones.
Groups: Fish, Amphibians, Reptiles, Birds, Mammals.
🦗 Arthropods
Exoskeleton + jointed legs.
Includes:
Insects – 6 legs, 2 antennae.
Arachnids – 8 legs, no antennae.
Crustaceans – 10+ legs, 2 pairs of antennae.
Myriapods – Many legs.
2.
Plant Kingdom
Cell walls made of cellulose.
Some cells have chloroplasts (for photosynthesis).
🌿 Types of Plants
Ferns: Reproduce via spores.
Flowering plants: Reproduce via seeds.
🌸 Monocotyledons (Monocots)
1 cotyledon.
Parallel leaf veins.
Random vascular bundles.
Flower parts in 3s.
Roots from the stem.
🌻 Dicotyledons (Dicots)
2 cotyledons.
Net-like leaf veins.
Vascular bundles in a ring.
Flower parts in 4s or 5s.
Main root with side roots.
3.
Fungi
Cell walls and nuclei.
Do not photosynthesise.
Made of hyphae (microscopic threads).
Reproduce via spores.
Decomposers – release nutrients by breaking down matter.
4.
Protoctists
Mostly unicellular.
Some resemble animals or plants.
E.g., algae, amoeba.
5.
Prokaryotes
No true nucleus.
Unicellular.
Bacteria and similar organisms.
🦠 Viruses (Not Living Organisms)
Not in any of the five kingdoms.
Do not have cells.
Made of genetic material inside a protein coat.
Do not show the 7 characteristics of life.
🧠 Tips for Using a Dichotomous Key
Each step should have two contrasting options.
Avoid subjective terms (e.g., “large”).
Work through one organism at a time.
Absolutely! Here’s a comprehensive worksheet with questions for every definition based on your notes. You can print this, use it for revision, or turn it into flashcards.
📄
Worksheet: Classification & Characteristics of Living Organisms
✏️ Instructions:
For each question, write your answer in the space provided. Try to answer using your own words when possible.
🔬
Section 1: Characteristics of Living Organisms
What is respiration?
Define the process and its purpose.
What does metabolism refer to in a living organism?
Give an example of a metabolic process.
How does sensitivity help organisms survive?
Give an example of sensitivity in humans or animals.
What is meant by growth in biology?
What does “dry mass” mean in this context?
Define reproduction.
Why is reproduction important for a species?
What are the seven characteristics of living things? List them.
🧬
Section 2: Classification and Naming
What is a kingdom in biology?
Name the five major kingdoms.
What is a species?
What is required for two organisms to be the same species?
What does the binomial system involve?
Write an example and label the genus and species.
What is a dichotomous key and how is it used?
Why should we avoid using words like “large” or “tall” in a key?
What is a common ancestor?
Why is this important in classification?
🧑🔬
Section 3: Kingdom-Specific Terms
🔹
Animal Kingdom (Mammals & Arthropods)
What is the function of the pinna in mammals?
Describe the role of the placenta.
What are mammary glands and their function?
What does the diaphragm do in mammals?
What is an arthropod?
Name three examples.
What is an exoskeleton and what does it do?
What does terrestrial mean?
Define vestigial.
Can you name a vestigial structure in humans?
🔹
Plant Kingdom
What is cellulose and where is it found?
What does chlorophyll do for the plant?
What is the difference between monocotyledons and dicotyledons?
List two features for each.
🔹
Other Kingdoms
What is a fungus?
Why can’t fungi photosynthesise?
Define hyphae.
What is a protoctist?
Give an example.
What is a prokaryote?
How is it different from a eukaryote?
What does multicellular mean?
Give an example of a multicellular organism.
What does unicellular mean?
Give an example of a unicellular organism.
🔹
Other Important Terms
What are organic substances in biology?
What is a spore?
Which organisms use spores for reproduction?
Define metamorphosis.
Name one animal that undergoes metamorphosis.
Why are viruses not placed in any of the five kingdoms?
What features do they lack?
✅
Challenge Section: Application Questions
A frog lays eggs in water. Its young hatch into tadpoles and later turn into adult frogs. What life process is this?
A scientist finds a green organism with a cell wall and parallel leaf veins. Which plant group might this belong to?
A student finds an organism with an exoskeleton, jointed legs, and two antennae. Is it a vertebrate or an arthropod?
Certainly! Here’s the complete worksheet with answers for all the definitions and questions you’ve provided. This version is ideal for revision, checking your understanding, or studying for tests.
📄
Worksheet with Answers: Classification & Characteristics of Living Organisms
🔬
Section 1: Characteristics of Living Organisms
What is respiration?
🟩 It is the chemical process in cells that breaks down nutrients to release energy for metabolism.What does metabolism refer to in a living organism?
🟩 It includes all chemical reactions that occur in an organism to maintain life, such as respiration and digestion.How does sensitivity help organisms survive?
🟩 It helps organisms detect and respond to changes in their environment, such as moving away from danger or towards food.What is meant by growth in biology?
🟩 Growth is a permanent increase in size and dry mass of an organism.
💡 Dry mass: The mass of an organism after all water has been removed.
Define reproduction.
🟩 It is the biological process that produces new individuals of the same species.What are the seven characteristics of living things?
🟩 Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition (Mnemonic: MRS GREN)
🧬
Section 2: Classification and Naming
What is a kingdom in biology?
🟩 One of the five major groups used to classify organisms based on shared characteristics.
Kingdoms: Animal, Plant, Fungi, Protoctist, Prokaryote
What is a species?
🟩 A group of organisms that can breed and produce fertile offspring.What does the binomial system involve?
🟩 It is a two-name system that includes the genus (capital letter) and species (lowercase), e.g., Homo sapiens.What is a dichotomous key and how is it used?
🟩 It is a tool made up of pairs of statements used to identify organisms. Each step helps narrow down the organism’s identity.What is a common ancestor?
🟩 A species from which two or more species evolved. All mammals, for example, share a common ancestor.
🧑🔬
Section 3: Kingdom-Specific Terms
🔹
Animal Kingdom
What is the function of the pinna in mammals?
🟩 It directs sound waves into the ear canal.Describe the role of the placenta.
🟩 It allows the exchange of nutrients, gases, and waste between mother and fetus.What are mammary glands and their function?
🟩 Glands that produce milk to feed young.What does the diaphragm do in mammals?
🟩 It is a muscle that aids in breathing by separating the chest and abdominal cavities.What is an arthropod?
🟩 An animal with jointed legs and an exoskeleton.
Examples: Insects, spiders, crabs
What is an exoskeleton and what does it do?
🟩 A hard outer structure that supports and protects the body.What does terrestrial mean?
🟩 Living on land.Define vestigial.
🟩 A structure that has lost most or all of its function through evolution.
Example: Human appendix
🔹
Plant Kingdom
What is cellulose and where is it found?
🟩 A carbohydrate found in plant cell walls that provides structural support.What does chlorophyll do for the plant?
🟩 It absorbs sunlight for photosynthesis.Difference between monocotyledons and dicotyledons?
🟩 Monocots:
1 cotyledon
Parallel leaf veins
🟩 Dicots:2 cotyledons
Net-like leaf veins
🔹
Other Kingdoms
What is a fungus?
🟩 An organism with cell walls and a nucleus, but no chlorophyll (cannot photosynthesise).Define hyphae.
🟩 Microscopic threads that make up the body of a fungus.What is a protoctist?
🟩 A single-celled organism or one with a simple structure. E.g., amoeba or algae.What is a prokaryote?
🟩 A unicellular organism without a true nucleus (e.g., bacteria).What does multicellular mean?
🟩 An organism made of many cells. E.g., humans.What does unicellular mean?
🟩 An organism made of only one cell. E.g., bacteria.
🔹
Other Important Terms
What are organic substances in biology?
🟩 Carbon-based compounds made by living organisms.What is a spore?
🟩 A small reproductive structure with a protective wall, used by fungi and ferns.Define metamorphosis.
🟩 The process of changing from larva to adult with a different body form.
Example: Caterpillar to butterfly
Why are viruses not placed in any of the five kingdoms?
🟩 They do not have cells and do not show the seven characteristics of life.
✅
Challenge Section: Application Questions
A frog lays eggs in water. Its young hatch into tadpoles and later turn into adult frogs. What life process is this?
🟩 Metamorphosis and reproduction.A scientist finds a green organism with a cell wall and parallel leaf veins. Which plant group might this belong to?
🟩 Monocotyledons.A student finds an organism with an exoskeleton, jointed legs, and two antennae. Is it a vertebrate or an arthropod?
🟩 Arthropod.
.
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