a3.2 HL classifications and cladistics

define classification

the process of grouping things based on their similarities

define speciation

forming of a new species

define taxonomy

the science of naming and classifying organisms

define cladogram

a tree diagram showing the similarities and differences between species with nodes (branching points) and where the longer lines show common ancestors

define terminal branches

ends that represent individual clades

define root/base

shows common ancestor

what are the benefits of a classification system

communication → biological information between scientists
predictions → if characteristics of taxonomic group is known, then information about the individual is also known
info about evolution

define morphological traits

physical characteristics of an organism

flaws of the system of classification based on only morphological traits

it doesn't take into account the evolutionary background of that organism and therefore the possible connections to other organisms

scientists taking a new approach to classification

rather than only basing it on morphology, similar diets, habitat, etc. scientists are using genetic analysis and discovering that some species were actually grouped incorrectly

what is wrong with a fixed ranking if taxa

its arbitrary → doesn't show gradation of variation

define cladistics

a method of classification of animals and plants that aims to identify and take account of only those shared characteristics which can be deduced to have originated in the common ancestor of a group of species during evolution

what does cladistics determine

evolutionary relationships by looking at nucleic acids and amino acid sequences

what are the advantages of cladistics

it shows evolutionary relationship

helps us understand the diversity of life

provides biologically meaningful way to group organisms

define the biological species concept

the idea that organisms are the same species when they have shared traits and can reproduce and produce fertile offspring

define binomial nomenclature

two terms that denote a species: the genus and specific species

what are the rules regarding binomial nomenclature

1. the genus name starts with a capital letter
2. species name starts with a lowercase
3. is always in italics, but when handwritten its underlined
4.after already being used once in a text, the Genus can be abbreviated to the first letter

what are the benefits of binomial nomenclature

it reflects evolutionary relationships (same genus: common ancestor) and enables scientists to talk in the same "language"

whats included in bacteria, eukaryota and archea

bacteria

cyanobacteria

heterotrophic bacteria

eukaryota

chromists

plants

animals

fungi

alveolates

rhodophytes

flagellates

basal protists

archea

halophiles

thermophiles