4.2.2 - classification Flashcards
classification
the process of grouping things based on their similarities
taxonomic hierarchy
an ordered series of progressively smaller categories
seven taxonomic categories
kingdom, phylum, class, order, family, genus, species
domain
a taxonomic category above the kingdom level
the three domains are archea, bacteria, and eukarya
reasons for classifying organisms
- to identify species
- to predict characteristics
- to find evolutionary links
species
a group of similar organisms that can breed and produce fertile offspring
binomial nomenclature
a system for giving each organism a two word scientific name that consists of the genus name followed by the species
reasons for binomial nomenclature
avoid mistakes, show organisms, give descriptive info, organized info
the five kingdoms
prokaryotes, protoctista, fungi, plantae, animalia
features of prokaryotae kingdom
- unicellular
- no nucleus or membrane bound organelles
- no visible feeding mechanism
features of protoctista kindgom
- unicellular
- nucleus and other membrane bound organelles
- nutrients aquired by photosynthesus or ingestion of other organisms
features of fungi kingdom
- eukaryotic
- cell walls of chitin
- lack chlorophyll
- heterotrophic
- consist of hyphae and mycelium
features of plantae kingdom
- multicellular
- nucleus and other membrane bound organelles
- chlorophyll
- autotrophic feeders
-store food as starch
features of anamalia kingdom
- multicellular
- a nucleus and other membrane bound organelles
- no chloroplasts
- move with the aid of cilia and flagella
- food stored as glycogen
- heterotrophic feeders
changes in classification system
scientists have been able to tests for new similarities so some organisms can fall under new or other pre existing categories
more study of genetics and biomols, studying evolutionary relationships
eukaraya
domain of all organisms whose cells have nuclei
archaea
domain of unicellular prokaryotes that have cell walls that do not contain peptidoglycan
bacteria domain
prokaryotes, cell walls have peptidoglycan
archaebacteria
can live in extreme environments
eubacteria
known as true bacteria found in all environments
phylogeny
evolutionary relationships between organisms
phylogenetics
evolutionary history of groups of organisms
phylogenetic tree
a family tree that shows evolutionary relationshops thought to exist among groups of organisms
evolution
change in a kind of organism over time
evidence for evolution - palaeontology
fossils are formed when animal and plant remains are preserved in rocks sediment is deposited on the earth to form layers of rock, which correspond to different geological ears
evidence provided by fossil record
fossils of simplest bacteria are found in oldest rocks, more complex are found in recent rocks
sequence in which organisms are found matches their ecological links
can show how closelt related organisms have evolved from the same ancestor
why the fossil record is incomplete
many early life forms were soft bodied, meaning they have left little or no traces behind
right conditons are rare
nowhere near all fossils have been found
comparative anatomy
the study of similarities and differences among structures of living species
homologous structures
structure that appears superficially different in different organisms but same underlying structures e.g vertebrate limbs
divergent evolution
when two or more species sharing a common ancestor become more different over time
comparative biochemistry
comparison of organisms protein (amino acid); if amino acid sequence is similar then the organisms are related
variation
any difference between individuals of the same species
interspecific variation
variation among members of different species
intraspecific variation
variation among members of the same species
causes of variation
genetic and environmental
genetic causes of variation
- alleles
- mutations
- meiosis
- sexual reproduction
- fertilisation (chance)
characteristic that is determined purely by genetic variations
blood group
environmental causes of variation
can be affected by climate, diet, accidents, culture and lifestyle
characteristics caused by both genetic and environmental
height, skin, colour
discontinuous variation
a characteristic that can only result in certain discrete values, e,g blood type - there are no in between factors
using a bar chart
continuous variation
variation measured on a continuum rather than in discrete units or categories
controlled by number of genes
normal distribution (bell curve)
mean, median, mode are all the same
bell shape
50% of values are less than mean, 50% are more
most values lie close to the the mean value
standard deviation
a computed measure of how much scores vary around the mean score
adaptation
inherited characteristic that increases an organisms chance of survival
3 types of adaptations
anatomical, behavoural and physiological
anatomical adaptations
structural features
- body coverings
- camoflague
- teeth
- mimicry
marram grass adaptations
rolled up leaves exposes the waterproof cuticle on the outside and means the stomata open into an inner humid space
behavioural adaptation
- survival behaviours
- courtship
-seasonal behaviours like migration and hibernation
innate behaviour
behaviour that an organism is born with and does not have to be taught - such as a reflex
learned behaviour
a behaviour that has been learned from experience or observation
physiological adaptation
- poison production
- antibiotic production
- waterholding
convergent evolution
process by whuch unrelated organisms independently evolve similarities when adapting to similar environments
examples of analogous structures
bird wing and insect wing, quills on a sea urchin, hedgehog and cactus
selection pressure
the environmental factors that favour certain phenotypes
steps of natural selection
- new alleles can arise through mutation
- organisms whose characteristics are best adapted to SP will have increased chance in survival and reproduction
- successful organisms pass on the allele for the advantageous characteristic
- continues until the frequency of the allele increases
- leads to evolution
modern examples of evolution
antibiotic resistant bacteria, peppered moths, sheep, blowflies and flavobacterium
how has molecular biology led to changes in the science of classification
RNA polymerase - similar in archaea and eukarya but not in eubacteria - suggesting relationship
nuclear DNA - genomes can be sequenced, meaning those that have similar genetic material are more closely related
RNA comparison - sequenced to see similarities
