Characteristics and Classification of Living Organisms.pdf

It contains information regarding different characteristics of life which include movement, sensitivity, reproduction , breathing, respirstion, growth.

1. Section I
Characteristics and Classification of
Living Organisms
iGCSE
Biology

2. Learning Outcomes
Characteristics
•To be able to list and describe the
characteristics of living organisms
•To define the terms
–Nutrition
–Excretion
–Respiration
–Sensitivity
–Reproduction
–Growth
–movement

3. Learning Outcomes
Classification
•To be able to define and describe the binomial
system of naming species
•To be able to classify the five main classes of
vertebrates
•To be able to list the main features used in the
classification of flowering plants, arthropods,
annelids, nematodes and molluscs
•To be able to list the main features used in the
classification of viruses, bacteria and fungi, and
their adaptation to the environment.

4. Learning Outcomes
Using Simple Keys
•To be able to use simple dichotomous keys
based on easily identifiable features.

5. Characteristics of living
organisms
iGCSE Biology
Section I
Characteristics and Classification of Living Organisms

6. Introduction to Living Things

7. What is Life?

8. Aliens land on Earth and watch things carefully
to tell whether they are alive or not.
Would an alien think this car is alive?

9. Why aren’t fluffy toys alive?

Fluffy toys often look like real
animals

10. Life Processes
•If something is alive it will carry out all of
the seven life processes.
–Movement
–Respiration
–Sensitivity
–Growth
–Reproduction
–Excretion
–Nutrition

11. Characteristics of Living Things
•M is for movement
–Animals move to find food, shelter or a mate.
–Plants do not move in the same way as
animals but move towards sunlight.

12. Characteristics of Living Things
•R is for reproduction
–Animals lay eggs or have babies.
–Seeds from plants grow into new plants.

13. Characteristics of Living Things
•S is for sensitivity.
–Animals find their way using their sense
organs such as the eyes or skin.
–Plants don’t have sense organs but do
respond to gravity and light.

14. Characteristics of Living Things
•G is for growth
–Growth is an increase in size
–Animals stop growing when they reach adult
size.
–Plants grow throughout their lives.

15. Characteristics of Living Things
•R is for respiration
–Respiration is the release of energy from food.
–This usually needs oxygen.

16. Characteristics of Living Things
•E is for excretion
–All living things produce waste.
–The removal of this waste is called excretion.
–Animals excrete through their lungs, kidneys
and skin.
–Plants shed their leaves in autumn

17. Characteristics of Living Things
•N is for nutrition
–All living things need food for energy, growth
and repair.
–Animals have to find their own food and eat
plants and other animals.
–Plants make their own food by the process of
photosynthesis.

18. Classification

19. Classification
•Classification makes the identification of
living organisms easier
•Organisms are sorted into groups
according to features they have in
common.
•The biggest group is kingdom

20. The five kingdoms
•Bacteria
–Very small and single-celled, no nucleus
•Protoctists
–Single celled, with a nucleus
•Fungi
–Cell walls contain chitin, with a nucleus
•Plants
–Multicellular organisms
–Can make food through photosynthesis
•Animals
–Multicellular
–Have to obtain food

21. Classification
•The basic unit of classification is the species.
–A species is a group of organisms that can breed
together to produce fertile offspring.

•Naming Species
–In the Binomial system organisms are identified by
two names
•Genus and species
•Genus always has a capital letter
–Examples
•Canis lupus – the wolf
•Panthera leo – the lion

22. Classification of Invertebrates
•The main groups of invertebrates are
–Arthropods
–Annelids
–Nematodes
–Molluscs

•Here are some examples

23. Arthropods
•Special features
–They are invertebrates
–They have a waterproof exoskeleton
–Their bodies are segmented
–They have jointed limbs

•Four main classes of arthropod
–Insects
–Arachnids
–Crustaceans
–Myriapods

24. Insects
•Examples
–Dragon fly
–Locust

•Key features
–Three pairs of legs
–Two pairs of wings
–One pair antennae
–Compound eyes
–Body – head, thorax and abdomen

25. Arachnids
•Examples
–Spider
–Tick

•Key features
–Four pairs of legs
–Body divided into head and abdomen
–Several pairs simple eyes
–Chelicerae for biting / poisoning prey

26. Crustaceans
•Examples
–Crab
–Woodlouse
•Key features
–Five or more pairs of legs
–Two pairs of antennae
–Head and abdomen
–Exoskeleton forms a hard carapace
–Compound eyes

27. Classification of viruses,
bacteria and fungi

28. Viruses, e.g. HIV
•Very small
•NOT cells
•Contain a strand of DNA or RNA
•Surrounded by a protein coat (capsid)
•Only life process they show is reproduction
(inside host cells)

29. Bacteria e.g. E. coli
•Small
•Cell wall, cell membrane and cytoplasm
•No nucleus, DNA is a single coil
•Some have a slime capsule
•Some have flagellae (for movement)

30. Fungi e.g. Mucor
•Multicellular fungi are composed of
hyphae
•Cell walls made of cellulose or chitin
•Do not photosynthesis
•Some produce spores

31. Classification of Plants

32. Classification of flowering plants
•Key features
–Multicellular organisms
–Cellulose cell walls and sap vacuoles
–Roots, stems and leaves
–Some cells contain chloroplasts
–Two groups
•Monocotyledons
•Dicotyledons
•The term cotyledon means “seed leaf”