1. Characteristics & Classification of Living Organisms Flashcards
Movement definition
an action by an organism or part of an organism causing a change of position or place
Respiration definition
the chemical reactions that break down nutrient molecules in living cells to release energy for metabolism
Sensitivity definition
the ability to detect or sense stimuli in the internal or external environment and to make appropriate responses
Growth definition
a permanent increase in size and dry mass by an increase in cell number or cell size or both
Reproduction definition
the processes that make more of the same kind of organism
Excretion definition
the removal from organisms of toxic materials, the waste products of metabolism (chemical reactions in cells including respiration) and substances in excess of requirements
Nutrition definition
the taking in of materials for energy, growth and development; plants require light, carbon dioxide, water and ions; animals need organic compounds, ions and usually need water
Species definition
A species is defined as a group of organisms that can reproduce to produce fertile offspring
In what ways can species be classified into groups
These species can be classified into groups by the features that they share
How are organisms classified in a binomial system?
He named organisms in Latin using the binomial system where the scientific name of an organism is made up of two parts starting with the genus (always given a capital letter) and followed by the species (starting with a lower case letter)
What is the sequence of classifications for the binomial system?
Kingdom, Phylum, Class, Order, Family, Genus, Species
Why do organisms share features?
Organisms share features because they originally descend from a common ancestor
In what way did organisms use to be classified?
Originally, organisms were classified using morphology (the overall form and shape of the organism, e.g. whether it had wings or legs) and anatomy (the detailed body structure as determined by dissection)
What allowed us to classify organisms more accurately?
As technology advanced, microscopes, knowledge of biochemistry and eventually DNA sequencing allowed us to classify organisms using a more scientific approach
What does it show if the base sequences in the DNA of two species are similar?
Studies of DNA sequences of different species show that the more similar the base sequences in the DNA of two species, the more closely related those two species are (and the more recent in time their common ancestor is)
What do the cells of all living organisms contain?
The cells of all living organisms contain the following:
- Cytoplasm
- Cell membrane
- DNA as genetic material (either found in the nucleus or free in the cytoplasm)
- ribosomes
- enzymes
Where can enzymes be found in a cell and what are they used for?
Enzymes for respiration (in many, but not all types of cells, found in mitochondria
What is the first division of living things in the classification system?
the five kingdoms
What are the 5 kingdoms of classification?
Animals Plants Fungi Protoctists Prokaryotes
What are the main features of all animals?
- they are multicellular
- their cells contain a nucleus but no cell walls or chloroplasts
- they feed on organic substances made by other living things
What are the main features of all plants?
- they are multicellular
- their cells contain a nucleus, chloroplasts and cellulose cell walls
- they all feed by photosynthesis
What are the main features of all fungi?
- usually multicellular
- cells have nuclei and cell walls not made from cellulose
- do not photosynthesise but feed by saprophytic (on dead or decaying material) or parasitic (on live material) nutrition
What do the cell walls of fungi cells contain?
chitin
What are the main features of all protoctists?
- most are unicellular but some are multicellular
- all have a nucleus, some may have cell walls and chloroplasts
- meaning some protoctists photosynthesise and some feed on organic substances made by other living things
What are the main features of all prokaryotes?
- often unicellular
- cells have cell walls (not made of cellulose) and cytoplasm but no nucleus or mitochondria
What is the cell wall of prokaryotes made from?
peptidoglycan
What are the 5 classes of vertebrates?
- mammals
- birds
- reptiles
- amphibians
- fish
What do all vertebrates have?
a backbone
What main features do mammals have?
- fur/hair on skin
- have a placenta
- young feed on milk from mammary glands
- external ears (pinna) visible
- warm-blooded
What main features do birds have?
- skin covered in feathers
- have 2 legs and 2 wings instead of forelimbs
- lay eggs with hard shell on land
- have a beak
- warm-blooded
What main features do reptiles have?
- dry, fixed scales on skin
- lay eggs with rubbery shells on sand
- cold-blooded
What main features do amphibians have?
- smooth, moist skin
- adults usually live on land (so have lungs)
- larvae live in water (so have gills)
- lay eggs without shells in water
- cold-blooded
What main features do fish have?
- loose, wet scales on skin
- gills to breathe
- lay eggs without shells in water
- cold-blooded
What characteristic do all arthropods have?
they have jointed legs
What main features do myriapods have?
- body consists of many segments
- each segment contains at least 1 pair of jointed legs
- 1 pair of antennae
What main features do insects have?
- 3 part body (head, thorax and abdomen)
- 3 pairs of jointed legs
- 2 pairs of wings
- 1 pair of antennae
What main features do arachnids have?
- 2 part body - cephalothorax and abdomen
- 4 pairs of jointed legs
- no antennae
What main features do crustaceans have?
- more than 4 pairs of jointed legs
- chalky exoskeleton formed from calcium
- breathe through gills
- 2 pairs of antennae
What features do all plants need to have?
At least some parts of any plant are green, caused by the presence of the pigment chlorophyll which absorbs energy from sunlight for the process of photosynthesis
What 2 examples of plants are in the plant kingdom?
Ferns and flowering plants
What features do ferns have?
- Have leaves called fronds
- Do not produce flowers but instead reproduce by spores produced on the underside of fronds
What features do flowering plants have?
- Reproduce sexually by means of flowers and seeds
- Seeds are produced inside the ovary found at the base of the flower
- Can be divided into two groups – monocotyledons and dicotyledons
What features do monocotyledons have?
- Flowers contain petals in multiples of 3
- parallel leaf veins
What features do dicotyledons have?
- Flowers from dicotyledons contain petals in multiples of 4 or 5
- Leaves from dicotyledons have reticulated leaf veins (meaning that they are all interconnected and form a web-like network throughout the leaf)
Are viruses part of any classification systems? Why?
Viruses are not part of any classification system as they are not considered living things
How do viruses survive?
They do not carry out the seven life processes for themselves, instead they take over a host cell’s metabolic pathways in order to make multiple copies of themselves
What does a virus contain?
Virus structure is simply genetic material (RNA or DNA) inside a protein coat
