classification and evolution Flashcards
Classification hierarchy - taxonomic
Dude, King Philip Came Over From Great Spain
Domain Kingdom Phylum Class Family Genus Species
Binomial Naming System
Genus - species
e.g. Homo sapiens
Genus always capitalised
species not capitalised
ALL underlined
no 2 species have the same generic and specific name, all species can therefore be distinguished from one another + this system is universal
Phylogenetic definition of species
a species is a group of organisms that are very similar in appearance, anatomy and genetics
Prokaryota
1 of 5 kingdoms
- both autotrophic and heterotrophic
- no nucleus
- no membrane-bound organelles
- small 70s ribosomes
- peptidoglycan cell walls
- smaller cells
e.g. E coli
Protoctista
1 of 5 kingdoms
- autotrophic AND heterotrophic feeding
- nucleus
- membrane-bound organelles
- 80s ribosomes
- some are sessile, some move by cilia and flagella
- mostly unicellular
e.g. Amoeba
Animalia
1 of 5 kingdoms
- heterotrophic feeding - ingestion
- nucleus
- membrane-bound organelles
- 80s ribosomes
- bigger cells
- store food as glycogen
- free movement - cilia, flagella, proteins
Fungi
1 of 5 kingdoms
- saprotrophic feeding (nutrients acquired by absorption from decaying material)
- nucleus
- membrane-bound organelles
- chitin cell wall
- uni/multicellular
- no mechanism for locomotion
Plantea
1 of 5 kingdoms
- autotrophic feeding
- nucleus
- membrane-bound organelles
- 80s ribosomes
- chloroplasts
- cellulose cell wall
- bigger cells
- store food as starch
Convergent evolution
- 2 unrelated species adapt to look similar
- 2 organisms with similar molecules will have evolved together
Cytochrome, C
- protein used in respiration
- protein is not identical in all species
- samples of C can show differences between species
DNA
- biological molecule found in ALL organisms
- provides a universal code for all organisms
- changes in the base sequence of DNA = mutations
- DNA and proteins, can be compared between different species to determine evolutionary relationships between them
3 Domains
- Bacteria
- Archaea
- Eukarya
Artificial vs Natural Classification
Artificial
- based on a few characteristics
- convenient
- X reflect evolutionary relationships
Natural
- based on many characteristics
- / reflect revolutionary relationships
Phylogeny
- study of evolutionary relationships between species
reveals which group an organism is related to and how closely related
reflected using phylogenetic trees
Natural Selection
Darwin’s observations:
- offspring similar to their parents
- no 2 individuals are identical
- organisms produce a large number of offspring
- populations remain stable
Theory
- competition within a population
- organisms best suited to the environment are more likely to survive
- their advantageous characteristic is determined by specific alleles
- these alleles passed onto offspring
- species changes over time to have more advantageous phenotypes for the environment in which it lives
Evidence for evolution
- mitochondrial DNA
- biological molecules
- fossil records
- comparative biochemistry
- comparative anatomy
Variation
intraspecific - between members of same species
interspecific - between different species
continuous - 2 extremes and intermediate values, regulated by more than 1 gene (polygenes), often influenced by environmental factors
discontinuous - distinct categories, no intermediate values, regulated by 1 gene, ONLY influenced by genetic factors
Genetic variation
- alleles; parental combination of genes can produce different outcomes
- mutations; physical and metabolic characteristics are affected
- meiosis; independent assortment of chromatids, crossing over
- sexual reproduction; mix of genetic information
Environmental variation
cannot be inherited e.g. scars, bruises
Antomical adaptations
physical features
- body coverings - hairs, scales, spines, shells, feathers
and waxy cuticle for plants - camouflage - hide from predators
- teeth - diet, meat (sharp canines) vs plant (molars)
- mimicry - fool predators
Behavioural adaptations
the way an organism acts (inherited or learnt from a parent)
- playing dead/ freezing
- courtship - attracting mates
- seasonal, migration, hibernation
Innate
through genes inherited
Learned
learned by observing other animals
Physiological adaptations
processes that occur inside an organism
- poison production
- antibiotic production
- water holding
- blinking
- temperature regulation
Evolution
all organisms exposed to selection pressures, the organisms better adapted are more likely to survive and reproduce, as a result of natural selection, these adaptations become more common in the population
Natural Selection
- organisms show variation in characteristics (alleles)
- organisms whose better adapted to the selection pressure has an increased chance of survival and successful reproduction
- less well-adapted organisms die or fail to reproduce
- successful organisms pass the allele which encodes for the advantageous characteristic, to their offspring
the proportion of individuals with advantageous characteristic, increases
frequency of allele increases in gene pool = evolution
Antibiotic resistance
- bacteria resis antibiotics due to mutations or when antibiotic courses are incomplete
- resistant bacteria survive and reproduce passing the resistant gene to offspring
this can lead to superbugs and bacteria resistant to a range of very strong drugs
bad for humans - reduced effectiveness of prescriptions
Variation
differences within a population/ between species
Domain vs kingdom
the domain is better - due to evidence it displays fundamental differences between bacteria and archaea which are both classified as prokaryotes in the kingdoms - specific
