Strategize a Smooth Tenant-to-tenant Migration and Copilot Takeoff
Biodiversity
1. HKDSE Biology – Biodiversity
Biodiversity
● Refers to the existence of a great variety of life forms in the planet Earth
7 Characteristics of Living Organisms
● Living organisms should have all the 7 characteristics in certain stages of life
1. Nutrition Organisms take in food for energy and to maintain life
2. Irritability Organisms react to changes in their environment
Organisms break down food in their cells to supply energy for
3. Respiration
body activities
Animals move from place to place using legs, wings or fins.
4. Movement
Plants generally move by growing
5. Growth Organisms increase in size and complexity
6. Reproduction Organisms produce offspring
Organisms remove waste products produced from chemical
7. Excretion
reactions inside bodies
By Michael Ho~* 1
2. HKDSE Biology – Biodiversity
Cell Type
● Cells can be divided into 2 types (prokaryotic and eukaryotic cell)
Prokaryotes:
Organisms having prokaryotic cells, e.g. bacteria
Eukaryotes:
Organisms having eukaryotic cells, e.g. fungi, plants, animals
Features Prokaryotic cell Eukaryotic cell
- No true nucleus - True nucleus
Nucleus
- No nuclear envelope - Nuclear envelope
- A single circular DNA - DNA associated with
Genetic material lying free in cytoplasm proteins forming
chromosomes in nucleus
Membrane bounded
organelles
Cell membrane
Size Smaller Larger
By Michael Ho~* 2
3. HKDSE Biology – Biodiversity
Classification of Organisms
● Separate organisms into different groups based on their features
● All organisms on Earth are classified into 3 domains and 6 kingdoms
(A) Classifying Organisms
Classification levels Amounts of organisms Similarities among organisms
Domain 域 The most The least
Kingdom 界 ︽
Phylum 門
Class 綱
︾ ︽
Order 目
︾
Family 科
︾
︽
Genus 屬
Species 種 The least The most
Species - A group of organisms that can interbreed to produce fertile offspring
(B) Naming of Organisms
● Each species has a scientific name consisting of 2 words
● The 1st word is the name of genus, the 2nd word is the name of species;
separated by space
● The 1st letter of the first word being capital, the rest all being small
● Underlined if written
Students should know the scientific name of modern human
Homo sapiens (Don't underline the space!)
By Michael Ho~* 3
4. HKDSE Biology – Biodiversity
3 Domains (Bacteria, Archaea, Eukarya)
Prokaryotes Eukaryotes
Domain Bacteria Archaea Eukarya
Kingdom Eubacteria Archaebacteria Protista Fungi Plantae Animalia
Phylum - - - - - -
Class - - - - - -
Order - - - - - -
Family - - - - - -
Genus - - - - - -
Species - - - - - -
Domain Bacteria and Archaea
● Bacteria domain has 1 kingdom, Eubacteria.
● Archaea domain has 1 kingdom, Archaebacteria.
Similarity between Bacteria and Archaea
● They are prokaryotes
- No true nucleus
Nucleus
- No nuclear envelope
- A single circular DNA lying free in
Genetic material
cytoplasm
Membrane bounded
organelles
Cell membrane
Size Smaller
By Michael Ho~* 4
5. HKDSE Biology – Biodiversity
● Unicellular (Each organism contains only 1 cell)
● Different shapes (rod, spherical, spiral shape)
● Different methods to obtain nutrients
by photosynthesis (use sunlight to make food)
by chemosynthesis (use minerals to make food)
parasitic 寄生 (live in/on other organisms' bodies)
saprophytic 腐生 (depend on dead organic compounds)
Differences between Bacteria and Archaea
Domain: Bacteria Domain: Archaea
(Kingdom: Eubacteria) (Kingdom: Archaebacteria)
Larger Smaller
Cell membrane is made of lipids Cell membrane is made of lipids (different
(similar to those of eukaryotes) structure than those in all other organisms)
Cell wall made of peptidoglycan Cell wall contains no peptidoglycan
Ribosomes more different from Ribosomes resemble more closely to
eukaryotes eukaryotes
Live in a wide variety of habitats Live in extreme environments
Example:
Hot springs (very hot)
Salt lakes (very salty)
Acid mine drainage (very acidic)
Deep ocean floor (anaerobic condition)
By Michael Ho~* 5
6. HKDSE Biology – Biodiversity
Domain Eukarya
● This domain has 4 kingdoms (1.Protista, 2.Fungi, 3.Plantae, 4.Animalia).
● They are eukaryotes with nucleus and membrane bounded organelles.
1. Kingdom Protista
Most are unicellular; if multicellular, lack differentiation
2 types of Protista: Algae (autotrophic) and Protozoans (heterotrophic)
(A) Algae (B) Protozoans
Varies from single cells, colonies, Unicellular
filaments to sheet-like forms
Autotrophic nutrition All 3 types of heterotrophic nutrition
Contain chlorophylls and carry out 1. Holozoic:
photosynthesis in chloroplasts Mobile (∵pseudopodia, flagella, cilia)
Feed on bacteria, yeast or protozoans
2. Parasitic
3. Saprophytic
Presence of cell wall made of No cell wall
cellulose
Most are aquatic Live in freshwater or marine, in damp
Some unicellular algae may live in soil or in plants and animals
soil or associate fungi to form
lichens
E.g. seaweeds E.g. amoeba
2. Kingdom Fungi
Unicellular/Multicellular
Heterotrophs: saprophytic, parasitic
Presence of rigid cell wall made of chitin
Body is made up of a network of hyphae
No roots, stems, leaves or chlorophyll
Use spores for asexual reproduction
Live in damp places
E.g. yeast (unicellular), mould and mushroom (multicellular)
By Michael Ho~* 6
7. HKDSE Biology – Biodiversity
3. Kingdom Plantae
Plants are divided into non-vascular plants and vascular plants
Autotrophic nutrition:
Contain chlorophylls and carry out photosynthesis in chloroplasts
Presence of cell wall made of cellulose
Non-vascular plants
Major group Characteristics
Mosses There is no vascular tissues
Possess simple leaves and stems
No true roots but possess rhizoids
for anchoring, absorption of water
and minerals
Asexual reproduction by spores
Lack cuticle so restricted to damp,
shady areas
Vascular plants
With vascular tissue
Have true roots, stems and leaves
Have vascular tissues for transport of water, mineral salts and soluble
food substances
Cuticle on leaf surface to reduce water loss
Major group Characteristics
Ferns Asexual reproduction by spores
which are stored in sporangia
Sporangia are located on the
undersurface of the leaf
By Michael Ho~* 7
8. HKDSE Biology – Biodiversity
Major group Characteristics
Gymnosperms They are trees with needle-shaped
leaves
Seeds are not enclosed in ovary
and hence not enclosed in fruits
Naked seeds are protected by
seed coat
They are found in cones
Angiosperms Seeds are enclosed, protected and
dispersed in ovary and hence
enclosed in fruits
Possess flowers
2 types of angiosperms:
Monocotyledons and Dicotyledons
Summary of Kingdom Plantae
Non-flowering plants Flowering plants
Mosses Ferns Gymnosperms Monocotyledons Dicotyledons
Possess leaves, stems and true roots
Possess simple
Large leaves Usually Leaves with
leaves and stems Leaves with
subdivided into needle-shaped veins in
and rhizoids veins in parallel
leaflets leaves network
No vascular
Possess vascular tissues
tissues
Reproduce by spores Reproduce by seeds
No cone Possess cone No cone
No flower/fruit Possess flowers/fruits
No cuticle Possess cuticle
Terrestrial (wet
Terrestrial (can live in dry places)
area only)
By Michael Ho~* 8
9. HKDSE Biology – Biodiversity
4. Kingdom Animalia
● Multicellular organisms
● Compose of eukaryotic cells without cell wall and chloroplasts
● Animals are divided into invertebrates and vertebrates
1) Invertebrates
Usually restricted body size as they lack supporting vertebral columns
E.g. Jellyfish 水母, Tapeworms 絛蟲, Earthworms 蚯蚓, Snails 蝸牛, Sea
urchin 海膽, Insects 昆蟲
2) Vertebrates
Divided into 5 groups:
(A) fish, (B) amphibians, (C) reptiles,(D) birds, (E) mammals
(A) Fish
Skin is covered with slimy scales
Gills present for gas exchange in both larvae stage and adult
stage
Present of fins for balance and movement
- External fertilization
- Lay eggs in water
- Poikilotherms
Students should realize that sea horses 海馬 (have gills) are fish.
(B) Amphibians
Skin is covered with moist naked skin
Present of gills in larvae stage; lungs and skin surface in adult
stage for gas exchange
- External fertilization
- Lay eggs in water
- Poikilotherms
Students should realize that salamanders 蠑螈 (have moist naked skin)
are amphibians.
By Michael Ho~* 9
10. HKDSE Biology – Biodiversity
(C) Reptiles
Dry skin is covered with hard scales
- Present of lungs for gas exchange
- Internal fertilization
- Lay eggs with hard shells on land
- Poikilotherms
Students should realize that crocodiles 鱷魚 (have dry hard scales) are
reptiles.
(D) Birds
Body is covered with feathers
Present of beak
- Present of wing for flying
- Present of dry scales on their legs
- Present of lungs for gas exchange
- Internal fertilization
- Lay eggs with hard shells on land
- Homoiotherms
- Parental care is highly developed
Students should realize that penguins 企 鵝 (have beak and no
mammary gland) are birds.
(E) Mammals
Skin is covered with hairs
Present of mammary glands to feed young
Young develops in uterus
(EXCEPT platypus 鴨嘴獸, spiny ant eater 食蟻獸- lay eggs)
Present of diaphragm
- Present of lungs for gas exchange
- Internal fertilization
- Homoiotherms
- Parental care is highly developed
Students should realize that bats 蝙蝠 (have hair), whales 鯨魚 (have
mammary gland), dolphins 海豚 (have mammary gland) are mammals.
By Michael Ho~* 10
11. HKDSE Biology – Biodiversity
Summary of Kingdom Animalia
Invertebrates Vertebrates
No backbone Possess backbone
Fish Amphibians Reptiles Birds Mammals
Unique Unique Unique Unique Unique
features: features: features: features: features:
-Slimy scales -Moist naked -Dry scales -Feathers -Hair
-Gills skin -Beak -Mammary
-Fins -GillsLungs glands
-Uterus
-Pinnae
-Diaphragm
Live in water Live in water
Most live on land
(aqueous) and on land
External fertilization Internal fertilization
Egg-laying Born alive
Eggs without shell Eggs with shells No eggs
Poikilotherm Homoiotherm
Dichotomous Key 二叉式檢索表
Key is a tool for identifying organisms
Done by sorting organisms into smaller groups according to their characteristics
Dichotomous key is the one commonly used, providing 2 alternative features at
each step
The key can be presented in 2 forms (sentence form and chart form)
By Michael Ho~* 11