Classification And Evolution Flashcards
Why do we classify animals
- to make it more convenient
- to make the study of living things more manageable
- to make it easier to identify organisms
- to help us see relationships between species
What are the 8 taxonomic levels
- domain
- kingdom
- phylum
- class
- order
- family
- genus
- species
What are the different domains
- archaea
- eubacteria
- eukaryotae
What are the different kingdoms
- plantae
- animalia
- fungi
- protoctista
- prokaryotae
What is the binomial naming system
A system that uses the genus name and the species name to avoid confusion when naming organisms
- same in all languages
Why do scientists use the binomial naming systems
- ensures all species are named the same globally
Biological definition of a species
Two organisms that can breed together to produce fertile offspring
Phylogenies definition of a species
Group of individual organisms that are very similar in appearance, anatomy, physiology, biochemistry and genetics
What features are used in classification
- observable features
- detailed evidence
What further groups did Aristotle classify animals and plants into
- live or more in water
- live or more on land
- move through the air
Description of prokaryotae
- no nucleus
- loop of DNA that is not arranged in linear chromosomes
- naked DNA
- no membrane bound organelles
Smaller ribosomes than in other groups - free-living or parasitic
Description of protoctista
- eukaryotic
- most single-celled
- show a wide variety of forms
- show various plant or animal-like features
- mostly free-living
- autotrophic or heterotrophic nutrition
Description of fungi
- eukaryotic
- either single-celled or have mycelium
- walls made of chitin
- cytoplasm that is multi nuclear
- mostly free-living and saprophytic
Definition of plantae
- eukaryotic
- multicellular
- cells surrounded by cellulose cell walls
- autotrophic (build simple molecules into larger organic molecules)
- contain chlorophyll
Description of animalia
- aukaryotic
- multicellular
- heterotrophic (break large molecules into smaller ones)
- usually able to move
What is autotrophic
Absorb smaller molecules and turn them into larger organic molecules
Wha is heterotrophic
Break larger organic molecules into smaller molecules
What is cytochrome c
A protein used in respiration
- all organisms that respire contain it
When comparing two amino acid sequences from different species what can we conclude
- if same, two species are closely related
- if different, two species are not as closely related
- more differences = less closely related
Structural differences between bacteria and the other domains
- different cell membrane structure
- flagella have different internal structure
- different enzyme for synthesising RNA
- no proteins bound to their genetic material
- different mechanisms for DNA replication for RNA synthesis
Features archaea share with eukaryotes
- similar enzyme for RNA synthesis
- similar mechanisms for DNA replication and RNA synthesis
- production of some proteins that bind to their DNA
What is classification
The process of sorting organisms into groups
What are artificial classifications
- based on only a few characteristics
- does not reflect any evolutionary relationships
- provides limited information
- is stable
What does natural classification do
- uses many characteristics
- reflects evolutionary relationships
- provides a lot of useful information
- may change with advancing knowledge
What is phylogeny
The study of the evolutionary relationships between species
- studying how closely relation different species are
What is natural selection
The term used to explain how features of th environment apply a selective force on the reproduction of individuals in a population
- those who are better suited to the environment are more likely to survive
What were the main observations Darwin made
- offspring generally appear similar to their parents
- no two individuals are identical
- organisms have the ability to produce large numbers of offspring
- populations in nature tend to remain fairly stable in size
What can we conclude from Darwin’s discoveries
- there is a struggle to survive
- better-adapted individuals survive and pass on their characteristics
- over time, a number of changes may give rise to a new species
What did the fossils discovered by Darwin show us
- in the past, the world was inhibited by species that were different from those present today
- old species have died out and new ones have arisen
- the new species that have appeared are often similar to the older ones found in the same place
How are biological molecules providing evidence for evolution
- certain molecules are found throughout the living world
- if two species have only separated recently, their biological molecules are very similar if not identical
- if species took separate evolutionary paths, their biological molecules are likely to differ
- molecules like cytochrome c show the patterns in change
What is interspecific variation
The difference between species
What is intraspecific variation
The variations between members of the same species
What is continuous variation
Variations where there are two extremes and a wide range of values in between
Examples of continuous variation
- height in humans
- length of leaves on an oak tree
- length of stalk of a toadstool
- number of flagella on bacterium
What is discontinuous variation
Where there are distinct categories and nothing in between
Examples of discontinuous variation
- gender
- flagella in bacteria (some or none)
- human blood groups
What are the types of variation
- continuous
- discontinuous
What are the causes of variation
- genetic
- environmental
What is genetic variation
Variation caused by possessing a different combination of alleles
What is environmental variation
Variation causes by response to environmental factors like light resistance
Characteristics caused by both environmental and genetic variation
- becoming taller due to a better diet, can’t grow tall if rest of family is small
- puberty effects which genes are active
- changes in environment can effect what genes are active
What is the definition of adaption
A characteristic that enhances survival in the habitat
What is a well-adapted organism able to do
- find enough food or photosynthesise well
- find enough water
- gather enough nutrients
- defend its self from predators and disease
- survive the physical conditions of its environment
- respond to changes in its environment
- have sufficient energy to allow to successful reproduction
What are the different types of adaptations
- anatomical
- behavioural
- physiological
What are anatomical adaptations
Changes in structural features
What are behavioural adaptations
Ways the organism has changed its behaviour to help it survive
What are physiological adaptations
Changes that affect the way that processes work
Examples of physiological adaptations
- being able to roll up leaves
- being able to close and open the stomata
- lignified cells in leaves to help with support
Characteristics of moles
- cylindrical body
- small eyes
- strong front legs
- large claws
- short furr
- short tail
- tough skin on nose for protections
What is convergent evolutions
Distantly related organisms evolve similar traits to adapt to similar necessities
Examples of convergent evolution
- fins to swim
- wings to fly
What are the steps of natural selection
- mutations creates an alternate version of an allele
- creates genetic variation between individuals in the species
- those with the advantageous characteristic survive and reproduce
- they pass on their advantageous characteristic
- next generation has a higher allele frequency of that characteristic
What is the mnemonic for natural selection
S - selective pressure
M - mutation
A - advantageous characteristics
S - survival
H - hanky panky (reproduction)
I - inheritance
T - time
What is stabilising selection
An average phenotypes is selected for
- the mean characteristic
Examples of stabilising selection
- number of eggs layed
- human birth weight
What is directional selection
Populations genetic variation shifts towards one phenotype
examples of directional selection
- colour of pepper moth
- length of giraffe neck
What is a gene pool
The number of genes and different alleles presenting in an interbreeding population
What are the causes of genetic variation
- random assortment
- crossing over
- random fertilisation
- mutations
What is geographical/allopatric isolation
When a species is separated by a physical barrier
What is speciation
The formation of a new species
What are the steps of speciation
- reproduction isolation (allopatric or sympatric)
- allele frequency changes
- different mutations
- different species are now unable to breed
What is sympatric isolation
When organisms aren’t able to breed but are in the same place
What are polymorphic genes
Influenced by the environment
What does polygenic mean
When multiple genes code for one phenotype
Genetic variation is p… and p…
Polygenic
Polymorphic
What are the two different types of reproductive isolation mechanisms
- prezygotic
- postzygotic
What are the different prezygotic mechanisms
- geographic isolation
- ecological isolation
- temporal isolation
- behavioural isolation
- mechanical isolation
What are the different types of postzygotic mechanisms
- hybrid in viability
- hybrid sterility
