Characteristics & classification of living organisms Flashcards
Movement or Locomotion
an action by an organism or part of an organism causing a change of position or place
Respiration
chemical reactions in living organisms that break down nutrient molecules and release energy for metabolism
Sensitivity or Irritability
the ability to detect or sense stimuli in the internal or external environment and to make appropriate responses
Growth
permanent increase in size and dry mass by an increase in cell size or cell number or both
Reproduction
the process that makes more of the same kind of organism
Excretion
the removal of toxic materials , waste products of metabolism and substances in excess of requirements
Nutrition
taking in nutrients which are organic substances and mineral ions to be used in growth, tissue repair, development and production of energy
Stimulus
the change in the internal or external environment such as HEAT or PAIN or LIGHT…..
Dry mass
mass of an organism after the removal of its water content
How to prepare dry mass
- Heat gently in an oven or an incubator at a low temperature (about 80 celcius degree)
- After a suitable period of time, leave it to cool and weigh it
- Repeat heating and reweigh until to successive weights become equal to make sure it has lost all of its water content.
Classification
Sorting living organisms into groups according to shared features in Morphology and Anatomy
Morphology
External features
Anatomy
Study of internal structure of living organisms
Classification groups
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
To make it easy
Keep Plate Clean Or Family Gets Sick
Species
A group of organisms that can reproduce and produce fertile offspring
Importance of classification
- To facilitate the study and identification of living organisms
- Aims to reflect evolutionary relationships
Binomial System
Giving each organism a name of two words
- the first represents Genus and begins with Capital letter
- the second name represents Species and begins with Small letter
- the name is written in LATIN in italics or underlined
Homo Sapiens
- Homo : Genus
- Sapiens : Species
Binomial system depends on
- Morphology
- Anatomy
- DNA
- Protein
The kingdoms
- kingdom prokaryotae or bacteria
- kingdom protoctista
- kingdom fungi
- kingdom plant
- kingdom animal
kingdom prokaryotae
- no nucleus
- no organelles except ribosomes
- ribosomes smaller than other kingdoms
- circular DNA not associated with protein
- circular rings of DNA called plasmids
- covered with slime capsule for protection
- cell wall made of murein (protein and carbohydrate)
- cytoplasm contains food in form of glycogen and lipids
- may have flagella used in movement
- may contain chlorophyll
- reproduce by simple binary fission
Effect of temperature
- in high temp many types can secrete thick coat around themselves forming spores to withstand high temp
- in very low temp activities of bacteria slows down but are not killed
kingdom protoctista
involve unicellular animals (known as protozoa) and multicellular organisms such as seaweeds
- cells contain nucleus
- some have cell wall and chloroplasts known as algae
kingdom fungi
- eukaryotic cells
- cell walls made of chitin
- most are multicellular but few are unicellular such as yeast
- never motile as they have no cilia or flagella
- body usually made of hyphae which are aspetate
- whole body is called mycelium
- reproduce by spores but yeast reproduce by budding
How fungus is adapted to obtain its food?
- has feeding hyphae branched in food substances
- feeding hyphae provide large surface area for production of extracellular enymes
- enzymes digest the surrounding food into small soluble molecules
- these molecules are absorbed by simple diffusion and active uptake
yeast
- unicellular
- reproduce by budding in favorable conditions but reproduce by spore formation in unfavorable conditions
- not parasitic organism
other types of fungi
- formed of hyphae
- reproduce by spore formation
- may be parasitic or saprophitic
kingdom plants (flowering plants)
- eukaryotic cells
- contain chlorophyll
- make food by photosynthesis
- cell wall made of cellulose
- produce flowers for reproduction
- produce fruits enclosing seeds
- seeds germinate in suitable conditions producing new plants
flowering plants
- Monocotyledons (Monocots)
- Dicotyledons (Dicots)
Monocots
- have narrow leaves
- parallel veins
- seed contains one cotyledon
- have fibrous root
- number of stomata is equal distributed in the upper and lower surfaces of the leaves
- floral parts such as petals are 3 or their multiples
Dicots
- have broad leaves
- branched leaves
- seed contains two cotyledons
- have main taproot system with lateral roots
- stomata are usually found in the lower surface
- floral parts are 4 or 5 or their multiples
Ferns
- plants with roots, stems and leaves
- leaves are called fronds
- do not produce flowers
- reproduce by spores
- parts that produce spores are called sporangia (singular: sporangium)
kingdom animal
- eukaryotic cells
- multicellular organisms
- often motile
- no cell wall
- heterotrophic organisms (means can not make their own food but obtain it by eating other organisms)
phylum vertebrate classes
- fish
- amphibians
- reptiles
- birds
- mammals
Fish
- have a stream-lined shape to decrease water resistance
- covered with scales for protection
- have lateral line for protection
- have gills for gas exchange
- have different colors according to their environment to hide from their enemies by camouflage
- have fins for movement
Amphibians
- have four limbs
- have moist skin with fine capillaries for gaseous exchange
- have external ear drum for hearing
- their eyes are protruded to be able to see while the body is submerged in water
- nostrils found at top of head to breathe while swimming
- they lay soft eggs in jelly like coat that hatch into tadpoles
- male has dark region below lower jaw which is the site of vocal sac
- have external gills for gas exchage
- have tails for swimming
- have stream-line shape to decrease water resistance
example: frog
Reptiles
- have dry scaly skin to reduce water loss
- lay eggs with water proof shells
- ear drums are deep inside their heads
- most of them have 4 short weak limbs so they slide along the ground
- body is divided into head, neck, trunk and tail
example: lizards, snakes and crocodiles
Birds
- are covered with feathers which:
- act as insulating layer
- decrease the density of the bird to help in flying
- is covered with a waterproof oil in order not to absorb water
- have beaks modified according to the type of food
- the four limbs are modified into wings
- have tails to control their direction during flying
- their ear drums are found deep in their heads
- females lay eggs with hard shells
Mammals
- have hairy skin or fur
- have external pinnae or flap
- have whiskers
- females have mammary glands that secrete milk
- have four limbs
- have teeth with different types
Examples: humans, cats, dogs and bats
Homeothermic (warm blooded)
only birds and mammals are warm blooded which means they have constant body temp which doesn’t change even when the surrounding temp changes
Example: the normal temp of humans is 37 celcius degree
Viruses
- are considered as link or intermediate stage between livings and non-livings
- its difficult to classify viruses among living organisms as they many characteristics of living and non living organisms
Viruses
characteristics
- have a core of DNA or RNA
- have proteins
- can reproduce
- have no cytoplasm or cell organelles
- do not carry out any function of life except reproduction inside living cells
- very much smaller than bacteria
- are parasites
- have a protein coat called cupsid that consists of units called capsomers
- have no cell membrane
phylum arthropods
- invertebrates
- have segmented body
- have exoskeleton made of chitin for protection and support
- have pairs of jointed legs to facilitate their movement
Classes of arthropods
- Insects
- Arachnids
- Crustaceans
- Myriapods
Insects
- body is divided into head, thorax and abdomen to facilitate their movement
- 3 pairs of jointed legs for rapid movement
- 1 pair of antenna for sensation
- have compound eyes for wide vision
- most of them have wings
- are small to hide from enemies
- have different colours for camouflage
- have exoskeleton for protection and support
Arachnids
- body divided into 2 parts only which are cephalothorax and abdomen to facilitate their movement
- have 4 pairs of jointed legs for rapid movement
- legs end with claws for catching prey
- have no wings
- have simple eyes
- have no antenna but a pair of pedipalps which are used to hold the prey
- have exoskeleton for protection
Crustaceans
- body is divided into 2 parts which are cephalothorax and abdomen
- 2 pairs of antenna for sensation
- 1 pair of stalked compound eyes for wide field of vision
- most of them are aquatic and respire by gills for breathing in water
- usually have more than 4 pairs of legs
Myriapods
- have segmented body, pairs of jointed legs and exoskeleton
- have head but body can’t be divided
- have a pair of legs at each body segment
- as it grows additional segments are formed
Example: millipedes
