Life sciences unit 2 - taxonomy

why do we classify organisms?

one reason is to organize them to help make the process of scientific research easier

3 criteria for classifying organisms

physical characteristics

behavioural characteristics

evolutionary relationships

who created the binomial nomenclature system

carl linnaeus

what are the rules for the carl linnaeus nomenclature system

typically two words

always italics/underlined if handwritten

first word's first letter is capitalized —> genus

second word is all lower case —> species

what are the 7 taxons of the classification system

mnemonic: katie, please come over for great snacks

kingdom

phylum

class

order

family

genus

species

kingdom is the most broad and species is most specific d

what are the 6 kingdoms

eubacteria

archaebacteria

protista

plantae

animalia

fungi

what is a species

a group of species that can breed together to produce fertile offspring

what are evolutionary relationships determined by

determined by DNA and protein structures

what is a dichotomous key

a tool that allows users to determine the identity of organisms primarily based on physical characteristics

what are dichotomous keys made up of

series of choices that leads to the correct name of the given organism

dichotomous meaning

divided in two parts

always will be two choices in each step until the organism is identified

do dichotomous keys start with general or specific characteristics

general

work towards progressively more specific characteristics

what are the two types of dichotomous keys

forking/tree key (pictographic)

go to keys (written)

define phylogeny

evolutionary relationships

what is a phylogenetic tree or evolutionary tree

branching diagram showing evolutionary relationships

what are branching diagrams called

phylogenetic tree

evolutionary trees

are organisms that are closer together on a cladogram more closely related or does this have no significance

more closely related

because they share a common ancestor

what do nodes in cladograms/phylogenetic trees represent

"hypothetical" common ancestors

cladograms vs phylogenetic trees

both show the relationships between organisms with the common ancestor

cladograms don't tell time or genetic distance while phylogenetic trees do

cladograms focus on the order that organisms evolved

what are homologous structures

structures that have similar anatomy but perform different tasks (e.g. horse's hoof and human hand)

indicate evolutionary relatedness despite functional differences

what are analogous structures

structures that are anatomically (e.g. bone structure) but perform similar functions (e.g. shark fins and dolphin flippers)

not classified as closely related despite functional similarities

what are embryological relationships

organisms that look the same as embryos (early stages of life) likely came from the same ancestor

what are biochemical relationships

organisms with the same chemicals (e.g. proteins) that likely came from the same ancestor

how do genetics/DNA affect evolutionary relationships

the more similar the DNA in organisms the more closely related the organisms are and resemble each other

what are molecular clocks

show DNA mutations over time

the more time has passed the more mutations there are

may or may not affect the organism

what are extremophiles

organisms that can live in extreme environments (e.g. deep sea, hydrothermal vents, deep in the earth crust, lakes of acid)

what is the domain

categories of organisms

what are the three domains

bacteria

archaea

eucarya

what are autotrophs

self sustaining organisms (e.g. plants)

produce their own source of carbon

what are heterotrophs

obtain carbon from organic molecules such as sugar (e.g. humans, fungi, protists)

what are the oldest and youngest organisms

youngest eukarya —> eukaryotic cells

oldest bacteria/eubacteria

what is archaea

evolved of bacteria

what two types of organisms have no nuclei, no organelles, are single celled and are relatively small in size

bacteria and archaea

are archaea closer in age to eukarya or bacteria

eukarya

what do all three of the domains have/are

all are/have cells —> cell theory

outside membranes

DNA and RNA

ribosomes that synthesize proteins

what organism has peptidoglycan in the cell wall

bacteria

what organism can live in harsh environments

archaea

extremophiles

examples of bacteria

e. coli

streptococcus

examples of archaea

methanogens

halophiles

examples of eukarya protista

amoeba, paramecium, slime moulds, giant kelp

examples of eukarya fungi

mushrooms, yeasts

examples of eukarya animalia

sponges, worms, insects, fish, mammals

domain of eubacteria

bacteria

domain of archaebacteria

archaea

domain of protista

eukarya

domain of plantae

eukarya

domain of fungi

eukarya

domain of animalia

eukarya

kingdoms of the domain eukarya

plantae, fungi, animalia, protista

cell type of the domain bacteria

prokaryotic

cell type of the domain archaea

prokaryotic

cell type of the domain eukarya

eukaryotic

number of cells in the domain bacteria

unicellular

number of cells in the domain archaea

unicellular

what do colonial organisms mean

unicellular organisms that clump together to form colonies

number of cells in the domain eukarya and kingdom protista

most unicellular

some multicellular

some colonial

number of cells in the domain eukarya and kingdom plante

multicellular

number of cells in the domain eukarya and kingdom fungi

most unicellular

some multicellular

number of cells in the domain eukarya and kingdom animalia

multicellular

are kingdoms or domains more broad

domains

what is the method of obtaining energy for the domain bacteria

most heterotrophs

some autotrophs

what is the method of obtaining energy for the domain archaea

most heterotrophs

some autotrophs

what is the method of obtaining energy for the domain eukarya and kingdom plantae

autotrophs

what is the method of obtaining energy for the domain eukarya and kingdom fungi

heterotrophs

what is the method of obtaining energy for the domain eurkarya and kingdom animalia

heterotrophs