Ch. 1 - Characteristics and classification of living organisms Flashcards
What is biology?
The study of organisms
What is an organism?
A living thing
What do all organisms share?
Seven key characteristics
What are the seven characteristics of living organisms?
- Movement
- Excretion
- Sensitivity
- Growth
- Reproduction
- Nutrition
- Respiration
What is movement?
The ability of an organism to change position or place
Do plants perform movement?
Yes. Furthermore, their chloroplasts are moving about inside them
What is respiration?
Respiration is the chemical reactions in cells that break down nutrient molecules (usually from glucose) and release energy for metabolism
What is sensitivity?
The ability to detect and respond to changes in the environment (either internal environment or external)
What is growth?
Permanent increase in size and dry mass (pufferfish - no)
How to measure growth with dry mass?
- Comparing masses of identical organisms over time
- Kill one
- Let it dry
- Find mass without water
- Repeat with other organisms in the future and compare
What is reproduction?
The processes with make more of the same kind of organisms
What is excretion?
Process by which an organism gets rid of unwanted substances (either toxic or in excess)
What is nutrition?
Taking in materials which contain chemicals and energy for growth, development, and energy
How do biologist classify living organisms?
Based on how closely they think they are related
What is a common ancestor?
A species that lived in the past and is thought to have given rise to several different species
How else are living organisms classified?
Based on shared characteristics which suggest they are related
What is a species?
Smallest group in which we can fit living organisms, their offsprings are fertile
Example of infertile offspring?
Mule (from horse + donkey)
How do we name living organisms?
Through the binomial system
What is the binomial system?
An international agreed way of scientifically naming species (first name: genus, second name: species)
What is a genus?
Group of species that share similar features and a common ancestor
How to identify organisms?
Through dichotomous key
What is a dichotomous key?
A set of descriptions given two at a time from which you have to choose only one
What are kingdoms?
Biggest group in which we can divide living organisms
Characteristics of the animal kingdom?
- Have nucleus
- Don’t have cell walls or chloroplasts
- Feed on organic substances made by other living organisms
- Move freely
Characteristics of the plant kingdom?
- Have a nucleus
- Have cell walls made of cellulose
- Have chloroplasts
- Contain chlorophyll
- Stay in one place
- Spreading shape –> to absorb sunlight
- Feed on photosynthesis
How do plants eat?
By photosynthesis, chlorophylls absorb sunlight and use energy to make sugars
What do plants usually have?
Steam, leaves, roots, (sometimes) flowers
What is a chlorophyll?
Green pigment which absorbs energy from sunlight and uses it to combine CO2 and H2O to produce sugars (glucose)
What is cellulose?
A carbohydrate
Characteristics of the fungi kingdom?
- Multicellular except for yeast (unicellular)
- Have nuclei
- Don’t have chlorophylls
- Have cell walls (not made out of cellulose)
- Feed on waste organic materials / dead organisms
- Many are decomposers
- Made out of hypae
- Do not photosynthesise
- Reproduce through spores
What are hypae?
Small threads of many cells joined end to end
What are spores?
Groups of cells surrounded by a protective wall
What is yeast used for?
Make ethanol and bread
What is the protoctist kingdom?
Contains mixed collection of organisms
Characteristics of protoctists?
- Multicellular or unicellular
- May or may not have a cell wall and chloroplasts
- Feed by photosynthesis or organic stuff
What is the procaryote kingdom?
Contains huge number of organisms
Characteristics of procaryote kingdom?
- Usually unicellular
- They have no nucleus
- Have cell walls (not made out of cellulose)
- They have no mitochondria
- They have a circular loop of DNA –> free in cytoplasm
- Often have plasmids
What are the phylum in animal kingdom?
- Vertebrates
- Arthropods
Which are the classes of vertebrates?
- Fish
- Reptiles
- Birds
- Mammals
- Amphibians
Characteristics of fish?
- Have gills during WHOLE life
- Scaly skin
- Have fins
- Eggs have no shell and laid in water
- Usually live in water, some of them can stay on Earth for short periods
Characteristics of amphibians?
- Skin and no scales
- Eggs laid in water but live on land
- Undergo metamorphosis –> from larva to adult body
- Have gills initially but then lungs
- Tadpoles live in water, adults on land
Characteristics of reptiles?
- Scaly skin
- Don’t breed in water
- Eggs have soft shells (waterproof)
Characteristics of birds?
- Only animals with feathers
- Have scales only on legs and not always
- Eggs have hard shell
- Have a beak
- Front two limbs are wings –> not all of them can fly
Characteristics of mammals?
- Have a uterus
- Have a placenta (organ used to connect foetus to mother and allows exchange between them)
- Have mammary glands –> used to produce milk to feed young
- Have diaphragm –> muscle that separates chest cavity from abdominal cavity
- Hair on skin
- Have a pinna (ear flap) –> used to direct sound
- Have sweat glands
- Have different kinds of teeth
What is a placenta?
Organ which connects foetus and mother and allows exchange between them
What is a pinna?
Ear flap on outside of ear used to redirect sound
What are arthropods?
Phylum of animals
Characteristics of arthropods?
- Jointed legs
- No backbone
- Exoskeleton (outside of body)
What are the classes of arthropods?
- Insects
- Crustaceans
- Arachnids
- Myriapods
What are the characteristics of insects?
- Three pair of jointed legs
- Two pair of wings which could be vestigial
- Breathe through trachea
- Body divided into head, thorax, and abdomen
- Have one pair of antenna
- Mainly terrestrial
Why are trachea useful?
Stop water from evaporating and allow insects to live at dry temperatures
What does vestigial mean?
Description of a structure which has evolved so much to become small and useless
What are the characteristics of crustaceans?
- Two pair of antennas
- More than four pairs of jointed legs
- Breathe through gills –> live in wet places
- Most of them are aquatic
What are the characteristics of arachnids?
- Four pairs of jointed legs
- No antennae
- Body divided into abdomen and cephalothorax
What are the characteristics of myriapods?
- Body made of many similar segments
- Each segment has legs
- One pair of antennae
What are the two phylums of plants?
- Ferns
- Flowering plants
What are the characteristics of ferns?
- Leaves called fronds
- Have roots, steam, and leaves (fronds)
- Don’t have flowers
- Reproduce through spores on the underside of fronds
What are the characteristics of flowering plants?
- Have leaves, steams, roots, flowers
- Reproduce through seeds and flowers
- Seeds produced into ovary inside flowers
In what are flowering plants divided?
- Dicotyledons
- Monocotyledons
What are the characteristics of monocotyledons?
- Seeds with one cotyledon
- Parallel veins
- Roots grow out from steam
- Flower parts in multiple of tree
- Have vascular bundles in steam arranged randomly
What is a cotyledon?
A ‘‘seed leaf’’
What are the characteristics of dicotyledons?
- Seeds with two cotyledons
- Network of veins
- Roots grow out from main root
- Flower plants in multiple of four/five
- Vascular bundles in steam arranged in a ring
