1 Characteristics and classification of living organisms Flashcards
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 metabollism
sensitivity
the ability to detect and respond to changes in the internal or external environment
growth
permanent increase in size and dry mass
reproduction
the processes that make more of the same kind fo organism
excretion
the removal of toxic substances, waste production of metabolism, and substances in excess of requirement
nutrition
the taking in of materials for energy, growth and development
how are organisms classified into groups
organisms that share the same features can be classified into groups
species
a group of organisms that can reproduce to produce fertile offspring
binominal system of naming species
an internationally agreed system in which the scientific name of an organism is made up of two parts showing the genus and species
e.g. Homo sapiens
Homo = genus
Sapiens = species
what to classification systems aim to reflect?
evolutionary relationships
3 ways of classifying organisms
Comparing DNA base sequences
Comparing amino acid sequences
Comparing cellular structures
How do DNA sequences help classify organisms?
the more similiar 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)
DNA sequences of groups of organisms with a recent ancestor compaired to groups of organisms who share a distant ancestor
Recent ancestor group have base sequences in DNA that are more similiar than those who share only distant.
mnemonic to remember classification system
KING PHILLIP CAME OVER FOR GRAN’S SPAGHETTI
Classification system from general to specific
Kingdom
Phylum
Class
Order
Family
Genus
Species
Five kingdoms are:
Animals, Plants, Fungi, Protoctists, Prokaryotes
Main features of animals
- multicellular
- contain a nucelus but no cell walls or chloroplasts
- feed on organic substances made by other living things
main features of plants
- multicellular
- contains a nucleus, chloroplasts, and cellulose cell walls
- feed by photosynthesis
what do the cells of all living organisms contain?
cytoplasm, cell membrane, DNA as genetic material
With microscope: ribosomes and enzymes
main features of fungi
(e.g. moulds, mushrooms, yeast)
- usually multicellular
- cells have nuceli and cell walls (contains chitin not cellulose)
- feed by saprophytic (on dead or decaying material) or parasitic (on live material) nutrition
main features of protoctists
(e.g. Amoeba, Paramecium, Plasmodium)
- most are unicellular, but some are multicellular
- all have nucleus, only some have cell walls and chloroplasts
- some photosynthesis and some feed on organic substances made by other living things
main features of all prokaryotes
(bacteria, blue-green algae)
- unicellular
- have cell walls (not made from cellulose) and cytoplasm, but no nucleus or mitochondria
main features of mammals
- fur/hair on skin
- have a placenta
- young feed on milk from mammary glands
- external ears (pinna) visible
- endothermic / warm blooded
main features of birds
- skin covered in feathers
- 2 legs and 2 wings instead of forelimbs
- lay eggs with hard shells on land
- have a beak
- endothermic
main features of reptiles
- dry, fixed scales on skin
- lay eggs with rubbery shells on land
main features of amphibians
- smooth, moist skin
- adults usually live on land (so have lungs)
- larvae live in water (have gills)
- lay eggs without shell in water
main features of fish
- loose, wet scales on skin
- gills to breathe
- lay eggs without shells in water
what are the five vertebraes (animals with backbones)
reptiles, fish, amphibians, birds and mammals
what are the four invertebrates?
myriapods, insects, arachnids, crustaceans
main features of myriapods
- body consists of many segments
- each segment contains at least 1 pair of jointed legs
- 1 pair of antennae
(CENTIPEDE)
insects
- 3 part body (head, thorax and abdomen)
- 3 pairs of jointed legs
- 2 pairs of wings (1 or 2 can be non functional or undeveloped)
- 1 pair of antennae
(BUTTERFLY)
arachnids
- 2 part body (cephalothorax and abdomen)
- 4 pairs of jointed legs
- no antennae
(SPIDER)
crustaceans
- more than 4 pairs of jointed legs
- chalky exosheleton (formed from calcium)
- breathe through gills
- 2 pairs of antennae
(CRABS)
main features of ferns
- have leaves called fronds
- do not produce flowers but instead reproduce by spores produced on the underside of fronds
main features of flowering plants
- reproduce sexually
- seeds are produced inside ovary found at the base of the flower
- divides into two groups: monocotyledons and dicotyledons
monocotyledons in terms of flowers and leaves
contain petals in multiples of 3
leaves have parallel leaf veins
dicotyledons in terms of flowers and leaves
contain petals in multiples of 4 or 5
leaves have reticulated leaf veins (all interconnected and form a web like network)
virus
- non living (so not in classi system)
- do not carry out 7 life processes
- take over a host cell’s metabolic pathways in order to make multiple copies of themselves
- structure is simply genetic material (RNA or DNA) inside a protein coat
dichotomous meaning
branching into two
dichotomous key
used to identify organisms based on a series of questions about their features
