3.1.2b - Classification Processes - Species Flashcards
define classification
Putting things into groups
define taxonomy
the identification and naming of organisms
define Heirarchy
a system of ranking where small gorups are nested within larger ones
describe the Linnaean system of classification
- large groups being divided up into progressively smaller groups by their physical characteristics
- a taxon is any group within a system of classification and is a collection of organisms sharing some basic features
what is the order of the Linnaean system?
Domain: three domains
Kingdom: Five kingdoms
Phylum: Grouping of classes that share common features
Class: Grouping of similar orders
Order: Grouping of related families
Family: Grouping of similar genera
Genus: Group of species that are very closely related
Species: A group of organisms that share many common characteristics and which can interbreed to produce fertile offspring
what is the mnemonic to remember linnaeus classification order
dirty - domain
king - kingdom
phillip - phylum
comes - class
over - order
for - family
good - genus
sex - species
describe the features of the Linnaean system of classification
- hierarchial rank-based structure of classifying organisms
- Three domains, divided into kingdoms, phyla, classes, orders, families, genus and species
- uses binomial nomenclature to name classified organisms at the Genus species level
- uses morphological features of organisms to create groups according to their similarities/features of the groups become more similar at each lower taxon
describe the features of Asexual reproduction
- Involvesone parent only
- Gametes are not produced
- Offspring are genetically identical to the parent
- the cell division are only mitotic
- large number of plants are produced in a very short time
describe the features of sexual reproduction
- Involves two organisms
- Gametes are produced by the organisms
- offspring show genetic variation
- Gametes are produced by meiotic divisions and zygote develops by mitotic division
- comparatively the number produced is less
what are the advantages of Asexual reproduction?
- does not require special cells or a lot of energy
- can produce offspring quickly
- in a stable enviornment creates large, thriving population
what are the disadvantages of Asexual reproduction?
- limited ability to adapt
- face massive die-off if environment changes
what are the advantages to sexual reproduction?
- lots of variation within a species
- able to live in a variety of environmental settings
- able to adapt to changes in the environment
what are disadvantages of sexual reproduction?
- needs time and energy
- produce small populations
what are the 2 methods of sexual reproduction?
- r-strategists
- k-strategists
what are the features of an r-strategist?
- short life
- rapid growth
- early maturity
- many small offspring
- little parental care
- little investment in individual offspring
- adapted to unstable environment
- pioneers, coloniziers
- niche generalists –> able to adapt to many locations
- prey
- regulated mainly by external factors
- lower trophic level
what is an example of an r-strategist?
- rabbit
- bacteria
- plants that growth annually
what does the population graph of r-stategists look like and why?
- controlled by density independent factors
- e.g. climatic events, fires
what are the features of a k-strategist?
- long life
- slower growth
- late maturity
- fewer large offspring
- high parental care and protection
- high investment in individual offspring
- adapted to stable environment
- later stages of succession
- niche specialists
- predators
- regulated mainly by external factors
- higher trophic levels
what are some examples of k-strategists?
- elephants
- humans
- trees
what does a K-strategist graph look like and why?
- relatively stable
- density independent
- limited by carrying capacity
what are the 4 species interactions that are used to classify?
- predation
- competition
- symbiosis
- disease
define predation
- species 1 benefits
- species 2 is harmed
define competition
species/individual 1 is harmed
species/individual 2 harmed
- individuals are competing for space, resources, mates tec.
define interspecific competition
between members of different species
define intraspecific competition
between members of the same species
what are the 4 types of symbiosis?
- mutualism
- commensalism
- amensalism
- parasitism
define mutualism
both species benefit from the interaction
- e.g. anemone protects clownfish, clownfish provides faecal matter for food
define commensalism
one species benefits, the other is unaffected
- e.g barnacles transported to plankton-rich waters by whales
define amensalism
one species is inhibited or destroyed and the other is unaffected
- e.g. barnacles transported to plankton-rich waters by whales
define parasitism
one species benefits to the detriment of the other species
- e.g. ticks or fleas feed on the blood of their canine host
what are the 4 organisms involved with disease?
- parasite
- pathogen
- host
- vector
define parasite
an organism that lives on or in another organism, causing it some harm
define pathogen
A biological agent that causes disease or illness
define host
An organism that harbours a parasitic, a mutualistic, or a commensalist guest (symbiont)
define vector
An organism that does not cause disease itself but which spreads by spreading pathogens from one host to another
define molecular phylogeny/cladistics
- comparing the sequence of DNA between species
what is the structure of DNA?
- made up of deoxyribose sugar and phosphate backbone, linked by four nitrogeneous bases
how do you compare DNA sequences of different species?
- the greater the difference in DNA sequences, more time is presumed to have passed since they shared a common ancestor
what is a molecular clock?
- used based on the assumption that differences in species are occurring at a regular time (i.e. 10 mutations every 10 000 years)
- the longer ago they shared a common ancestor, the more time there has been for substitution of genes to occur
how do proteins mutate based on molecular phylogeny?
- DNA is the recipe for building protein
- different amino acids make different proteins
what are the 3 different places DNA is found?
- plants: chloroplasts
- Mitochondria: nucleolus
- Eukaryotic cells: nucleus
recall by heart the 3 common assumptions of cladistics?
- Any group of organisms are related by descent from a common ancestor
- There is a bifuricating pattern of cladogenesis
- Change in physical characteristics occurs in lineages over time
explain what the cladistics assumption of ‘common ancestor’ means?
- no spontaneous spawning of species, meaning they all come from a descendant
explain what the cladistics assumption of ‘bifurcation’ means?
- when the lineage splits, it divides into exactly two groups
explain what the cladistics assumption of ‘physical change’ means?
- that characteristics of organisms change overtime
what does a phylogenic tree look like?
refer to photo
recall the 6 parts of phylogentic trees?
- node: where the lineages diverge
- branch: each line on a tree
- leaf: where the line ends (no new node follows)
- sister taxa: the closest relatives of another given unit in an evolutionary tree
- outgroup: a group that is less closely related than any one of the single ingroups are to each other
- root: the very first node that represents the common ancestor of all species
what does a clade visually look like on a phylogenetic tree?
refer to photo
what does extant vs extinct mean?
extant: living
extinct: dead
how do you read a lader-like tree vs a binary tree and interpret them?
- a ladder-like tree would be consistent with a group of HIGHLY divergent species
- a nearly complete binary tree would be consistent with a group of CLOSELY related species
how to you read a time rooted tree?
- look at the nodes and compare to the scale to determine the most recent common ancestor
- right to left = most recent to most distant
How do you read a genetic rooted tree?
- the horizontal branch lengths represent the difference in genetics between the different species
- need a ruler and measure ALL horizontal distances between the species
- most closely related = shortest distance
what is the morphological definition of a species?
- based on appearance
- e.g male vs female features
- e.g different stages of species life-cycle
- linneus system uses this
what is the biological definition of a species?
- the offspring of a species must be able to reproduce (i.e must be fertile)
what is the ecological definition of a species?
- the resources that the particular group of organisms uses, and depends on the specialised ecological niche the group occupies
