Characteristics and classification of living organisms.

movement

an action by an organism or part of an organism causing a change of position or place

respiration

the chemical reactions in cells that break down nutrient molecules and release energy for metabolism

sensitivity

ability to detect and

respond to changes in the internal or external environment

growth

a permanent increase in size and dry mass

excretion

removal of the waste products of metabolism, toxic materials and substances excess in requirements

nutrition

taking in of materials for energy, growth, and development.

plants need CO2, light, water, ions.

animals need organic compounds, ions and usually water

reproduction

processes that make more of the same kind of organism

species

a group of organisms that can reproduce to produce fertile offspring

mammals

have hair and fur

warm blooded

give birth to live young

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binomial system

an internationally agreed system of naming species, in which the scientific name of an organism is made up of two parts showing the genus and species.

dichotomous keys

they r used to identify organisms based onna series of of questions about their features

how do we modernly classify organisms

dna sequencing of different species helped to classify organisms using a more scientific approach

the more similar the base sequence in the DNa of two species, the more closely related those 2 species r

five kingdoms

animals, plants, fungi, prokaryotes, protoctists/protists

characteristic of animals

multicellular ingestive heterotrophs (they get their nutrition by eating other living things)

eukaryotic (their cells contain a nucleus, but no cell wall or chloroplasts)

characteristics of plants

multicellular autotrophs

eukaryotic - their cells contain a nucleus, cell wall and chloroplasts (cell wall made of cellulose)

They make their own organic nutrients/food, using energy from sunlight, through photosynthesis

characteristics of fungi

usually multicellular

have nuclei, cell wall not made of cellulose

they feed via

parasitic nutrition

saprophytic nutrition - feeding on dead material

don’t photosynthesise

characteristics protoctists

most unicellular, but some r multicellular

all have a nucleus, but some have a cell wall and chloroplasts

some get their nutrition by photosynthesise, and some feed on organic substances made by other living thing

characteristics of prokaryotes

often unicellular

cells have cell walls not made of cellulose, cytoplasm, no nucleus or mitochondria

circular chromosome of DNA that floats in the cytoplasm instead of a nucleus

vertebrate

include: mammals, birds, reptiles, amphibians, fish

mammal features

• have fur or hair

• young feed on milk from mammary glands

• external ears/pinna visible

• heart has four chambers

bird features

• have a beak

• lay eggs with hard shells

• have wings instead of forelimbs

• have feathers

reptile features

* have scaly skin
* lay eggs with rubbery shell

amphibian features

* moist skin without scales * lay eggs in water * larvae live in water so have gills * adults usually live on land so have lungs

gas exchange occurs through skin an lungs.

fish features

• gills

• fins, which are streamlined

• loose and wet scales

• almost all live in water except one or two

• cold-blooded

• lay soft eggs without shells in water

• external fertilisation

arthropods

invertebrates with joined legs

include:

arachnids

myriapods

insects

crustaceans

myriapod features

• body has segments

• each segment has a pair of jointed legs

• exoskeleton

• many legs

• many segments

• elongated bodies

insect features

* body divided into three segments - head thorax abdomen
* three pair of jointed legs
* two pair of wings

arachnid features

• four pair of jointed legs

• breath through structures called book lungs

• body divided into two parts: cephalothorax and abdomen

• no antennae

crustacean features

• four pairs of jointed legs

• not millipedes or centipedes

• breathe thru gills

• chalky exoskeleton made of calcium

fern features

have leaves called fronds

do not flower

reproduce via spores

flowering plant features

* they reproduce through flowering and seeds
* their seeds are produced in the ovaries, in the flower

monocotyledons

• fibrous roots

• veins run in parallel to one another

• petals/flower parts in multiples of three

• narrow and elongated leaves

dicotyledonous plants

• contain a tap root system

• broad leaves

• petals or flower parts in multiples of 4-5

• network of veins on leaves

viruses

* not considered living for they don't carry the seven life processes
* not part of any classification system
* they can only take over other cells to make more copies of themselves
* they are not made of cells they are just genetic material (either RNA or DNA) surrounded by a protein coat

classification systems aim to

reflect evolutionary relationships

sequences of bases in DNA are used as a means

classification

groups of organisms which share a more recent ancestor (are more closely related) have base sequences in DNA that are more similar than those that share only a distant ancestor

how does DNA help us identify people?

Individuals have different or unique DNA.

DNA has genes or alleles or sequence of bases.