Chapter 1 - Characteristics and Classification of Living Organisms Flashcards
what is an organism?
a living thing
what are the seven characteristics of living organisms? (MRS GREN)
movement, respiration, sensitivity, growth, reproduction, excretion, nutrition
growth
all organisms begin small and get larger by the growth of their cells and by adding adding new cells to their body (permanent increase in size and dry mass)
movement
all organisms are able to move to some extent, most animals can move their whole body from place to place and plants can slowly move parts of themselves (change of position or place)
sensitivity
all organisms pick up information about changes in their environment and react to these changes (internal or external environment)
excretion
the removal of waste products produced by metabolic reactions in excess of requeiments from the body
reproduction
organisms are able to make new organisms of the same species as themselves
nutrition
organisms take substances from their environment and use them to provide energy or materials to make new cells
respiration
all organisms break down glucose and other substances inside their cells to release energy that they can use (chemical reaction that breaks down nutrient molecules and release energy for metabolism)
metabolism
the chemical reaction that takes place in living organisms
species
a group of organisms that can reproduce to produce fertile offsprings
are donkeys and horses able to mate with one another? and if so is the offspring fertile?
even though they belong to two different species, they are able to reproduce with one another as they share the same genus, their offspring will be strong and healthy but infertile
binomial naming system
a system of naming species that is internationally agreed in which the scientific name is made up of two parts showing the genus and the species
genus
a group of species that are related to one another, share similar features and share a common ancestor
how is the binomial name written?
the genus comes first and is always written with a capital letter, the second name is the species it belongs to and is written with a small letter
dichotomous key
a way of identifying an organisms by working through pairs of statements (about its features) that lead you to its name
what is one piece of evidence that tigers and lions are related?
they share the same genus
what are two pieces of evidence that lions and tigers belong to different species?
they have different binomial names: panthera tigris and panthera leo as well as together they produce an infertile offspring
kingdom
one of the major groups into which all organisms are classified
what are the characteristic features of plants?
*their cells have a nucleus and cell walls made of cellulose and often contain chloroplasts
*they feed by photosynthesis
*they may have roots, stems, and leaves (some don’t have these organs)
what are the characteristic features of animals?
*their cells have a nucleus but no cell walls or chloroplasts
*they feed on organic substances made by other living organism
*they are multicellular
what are the characteristic features of fungi?
*they are usually multicellular but some such as yeast are unicellular
*they have nuclei and cell walls but the walls are not made of cellulose
*they don’t have chlorophyll
*they feed by digesting waste organic material and absorbing it into their cells
*spread or reproduce by spreading spores
*most have hyphae
what are the characteristic features of protoctists?
*they are multicellular or unicellular
*their cells have a nucleus and may or may not have a cell wall and chloroplast
*some feed by photosynthesis and others feed on organic substances made by other organisms
what are the main characteristic features of prokaryotes:
*they are usually unicellular
*they have no nucleus or mitochondria
*they have cell walls not made of cellulose
*they have a circular loop of DNA which is free in the cytoplasm
*they often have plasmid
what is a vertebrate?
animals that have a backbone
what are the characteristic features of fish?
*they have scaly skin
*they have gills throughout their life so they can breathe
*they have fins
*their eggs have no shell and are laid in water
what is metamorphosis?
changing from a larva with one body form to an adult with a different body form
what are the characteristic features of amphibians?
*smooth, moist skin
*their eggs have no shells and are laid in water
*the tadpoles live in water whilst adults often live on land
*tadpoles have gills for gas exchange and adults have lungs
what are the characteristic features of reptiles?
*dry, fixed scales on skin
*lay eggs with a soft shells on land
what are the characteristic features of birds?
*they have feathers and sometimes a few scales
*they have a beak
*their front two limbs are wings
*lay eggs with hard shells
*endothermic
what are the characteristic features of mammals?
*they have hair on their skin
*their young develop in the uterus attached to the mother by a placenta
*females have mammary glands which produce milk to feed their young
*different kinds if teeth: incisors, canines, premolars and molars
*pinna (ear flap) outside the body
*sweat glands in the skin
*they have a diaphragm
*endothermic
what are arthropods?
animals with jointed legs but no backbone (invertebrates)
what are the three standard features of arthropods?
*exoskeleton
*jointed legs
*segmented body
what are the characteristic features of insects?
*three pairs of jointed legs
*two pairs of wings (one or two may be vestigial)
*breathe through tubes called tracheae
*their body is divided into a head, thorax and abdomen
*one pair of antennae
*they are mainly land living
what are the characteristic features of crustaceans?
*more than four pairs of jointed legs
*two pairs of antennae
*chalky exoskeleton formed from calcium
*breathe through gills
*live in water
what are the characteristic features of arachnids?
*they have four pairs of jointed legs
*no antennae
*body divided into two parts - a cephalothorax (brain connected to thorax) and abdomen
what are the characteristic features of myriapods?
*body consists of many similar segments
*each of their body segments has jointed legs
*one pair of antennae
what are the characteristic features of ferns?
*plants with roots, stems and leaves (fronds)
*don’t produce flowers
*reproduce by spores produced on the underside of their fonds
what are the characteristic features of flowering plants?
*plants with roots, stem and leaves
*reproduce sexually using flowers and seeds
*their seeds are produced inside an ovary in the flower
*can be divided into two groups - monocotyledons (monocots) and dicotyledons (dicots)
what are the characteristic features of dicots?
*seeds with two cotyledons (seed leaves)
*usually have a main root with side roots coming from it
*leaves have a network of branching veins
*flower parts in multiple of four or five
*broad leaves
*vascular bundle in the stem arranged in a ring
what are the characteristic features of monocots?
*seeds with one cotyledons (seed leaves)
*roots grow out directly from the stem
*long narrow leads
*leaves have parallel veins
*flower parts in multiples of three
*vascular bundle in the stem arranged randomly
why are viruses considered a non-living organism?
as they cannot do anything other than just exist until they get inside a living cell, on their own they don’t display the seven characteristics of living things, they simply take over a host’s metabolic pathway in order to make multiple copies of themselves
what are spores?
tiny groups of cells with tough, protective outer covering
