Classification and evolution Flashcards
1
Q
Binomial system
A
A system that uses the genus name and the species name to avoid confusion when naming organisms
2
Q
Classification
A
The process of placing living things into groups
3
Q
Why do we classify living things
A
-convenience
-makes study of living things more manageable
-makes it easier to identify organisms
-helps see the relationships between species
4
Q
What were the first organisms classified into
A
Air, water, soil
5
Q
What is the modern classification hierarchy
(taxonomic groups)
A
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Daddy King Philip Came Over For Good Spaghetti
6
Q
Who devised the first system of classification and how did they do it
A
Carl Linnaeus
-grouped organisms based on similarity in their features
-divided into taxonomic groups, originally Kingdom, Class. Order, Genus, species but has been modified and expanded
7
Q
What is a domain
A
the highest taxonomic rank
three domains: archaea bacteria. eubacteria, eukaryote
8
Q
What is a kingdom
A
five kingdoms:
plantae, Animalia, fungi, protoctista - eukaryotes
prokaryote
9
Q
What is a phylum
A
group of organisms that all have the same body plan i.e. possession of backbone
chortada - nervous system protected by vertebal column
Arthropoda - hard exoskeleton and jointed limbs i.e insects and spiders
10
Q
What is a class
A
a group of organisms that possess all the same general traits
i.e. the same number of legs
11
Q
What is an order
A
sub-division of class using additional info about the organisms
i.e. mammal is divided into Carnivora and herbivore
12
Q
What is a family
A
a group of closely related genera
i.e. within Carnivora there is dogs and cats
13
Q
What is a genus
A
A group of closely related species
14
Q
What is a species
A
the basic unit of classification
- show some variation but are essentially the same
15
Q
What happens as you decrease in taxonomic groups
A
Becomes increasingly difficult to separate closely related species and to place accurately
16
Q
What is the binomial system (devised by Carl Linnaeus)
A
a system that uses the genus name and the species name to avoid confusion when classifying organisms
i.e. Homo sapiens
Homo - genus (always given uppercase first letter)
sapiens - species (written in italics/ underlined)
17
Q
Why does grouping organisms with a common name not work
A
- same organisms may have different common names in different parts of one country
- different names are used in different countries
- translations of languages may give dialects different names
-same common name may be used for same species in different parts of the world
18
Q
What is the universal language Linnaeus used
A
Latin
19
Q
What is the biological definition of a species and what’s wrong with it
A
’ a group of organisms that can freely interbreed to produce fertile off spring’
-does not work for organisms that can reproduce asexually/ fossils
20
Q
What is the phylogenetic definition of a species
A
’ a group of individual organisms that are very similar in appearance, anatomy, physiology, biochemistry, genetics ‘
21
Q
What do similar species all occupy
A
the same niche in an ecosystem
- this allowed for easier classification
- mistakes could still be made only could get even more accurate classification with microscopes
22
Q
What organisms did not fit into their kingdoms with the 2 kingdom classification
A
fungi - roots but do not photosynthesise
euglena - can move and photosynthesise
23
Q
What are the characteristics of an organism in the prokaryote kingdom
A
- have no nucleus
- loop of DNA that is not arranged in linear chromosomes
- naked DNA
- no membrane bound organelles
- smaller ribosomes then in other groups
- cells smaller than eukaryotes
- may be free living or parasitic
24
Q
What are the characteristics of an organism in the protoctista kingdom
A
- eukaryotic
- single celled (many algae are multicellular though)
- variety of forms ( only common feature is don’t belong to any of the other four kingdoms)
- show various plant/ animal features
- mostly free-living
- autotrophic/ heterotrophic nutrition - some photosynthesize, some ingest prey, some feed using extracellular enzymes, some are parasites
25
What are the characteristics of an organism in the plantae kingdom
- eukaryotic
- multicellular
- cells surrounded by a cellulose cell wall
- autotrophic (absorb simple molecules and build them into larger organic molecules)
- contain chlorophyll
26
What are the characteristics of an organism in the Animalia kingdom
- eukaryotic
- multicellular
- heterotrophic ( digest large organisms to form smaller molecules for absorption)
- usually able to move around
27
What is convergent evolution
two organisms can adapt in the same way and look very similar
- could be grouped in the same taxonomic group based on observable characteristics
28
How are biological molecules used in classification
- two organisms with similar are closely related as they have not evolved separately for long
- differences reflect the evolutionary relationships - backed up scientific research and clarify
29
What is cytochrome C
used in respiration - in all living organisms that respire
30
How can cytochrome C be used to classify organisms
- not identical in all living species
- different sequences of amino acid allows scientists to draw conclusions:
If sequences are the same must be closely related
If different not so closely related
More differences the less closely related the species
31
How does cytochrome C differ in humans and different organisms
humans and chimpanzees identical - close
Humans and rhesus monkey, one difference - close
Humans and dogfish, 11 differences - not close
32
What is DNA
- provides the genetic code, the instruction for producing proteins
- universal - particular sequence of DNA codes for same sequence of amino acids in all living organism
33
How can DNA be used in classification
- DNA can contain mutations
- compare DNA sequences- more similar the more closely related the two species
34
What is the three Domain classification
Carl Woese
- based ideas on RNA gene
- divided prokaryote into eubacteria and archaea bacteria
35
How is archaea bacteria similar to eukaryotes
( another fundamental difference to eubacteria)
- similar enzymes ( RNA polymerase) for synthesising RNA
- similar mechanisms for DNA replication and synthesising RNA
- production of some proteins that bond to their DNA
36
What did Woese argue about DNA and RNA
RNA and DNA are basic mechanisms that translates genes into visible characteristics
- differences between bacteria therefore fundamental
37
What are the two different types of classification
Artificial/ Natural
38
What is artificial classification and benefits
Done for convenience so easy to remember:
- based on a few characteristics
- doesn't reflect evolutionary relationships
- provides limited information
- stable
39
What is natural classification
taxonomic groups:
- uses many characteristics
- reflects evolutionary relationships
- provides lots of useful information
- may change with advancing knowledge
40
Why is natural classification between different organisms in the modern world useful
If you want to find out more about endangered species, research can be carried out on a similar species that is not endangered
- helps make conservation more successful
41
What is phylogeny
the study of evolutionary relationships between organisms
42
How does a phylogenetic tree work
-any two living species today had had a common ancestor alive in the past
-the time at which the two species start to evolve separately is a branch in the tree
- the more recent the common ancestor, the more closely related the two species
43
What did Darwin come up with
Natural Selection - features of the environment apply a selective pressure on the reproduction of individuals in an environment
44
What were Darwin's observations
- 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 stay the same size
45
What were Darwin's conclusions
- there is a struggle to survive
- better adapted individuals survive and pass on their characteristics
- over time a number of species gives rise to a new species
46
How are fossils used as evidence for evolution
They showed that modern species had similarities to the fossils, but had variations to adapt to their environment
47
How are biological molecules used as evidence for evolution
- biological molecules are in all living species, if one species gives rise to another suggests the same - all have one common ancestor
-more closely related, more similarities in biological molecules
- cytochrome c e.g.
48
How is mitochondria used in evolution
- mDNA is passed on through the mother during sexual reproduction
- mutates more as doesn't have the same proof reading systems as DNA
- lots of variations in mDNA in people in different parts of the world
- can be used to find origins of different races
49
What is standard deviation
A measure that spreads out the mean
-low means data has a low range and are grouped closely to the mean = reliable
-high means data has a large range and are less well grouped = unreliable
50
How do you work out the spread of the data sheet
mean +/- the standard deviation
if leaves show a normal distribution
68 % lies within range of mean +/- SD x1
98% lies within range of mean +/- SD x2
- anything outside is viewed as anomalous
51
What is the T-test
Used to compare two means, whether the difference between the two means is a significant difference
52
What must you do before starting the T-test
State a null hypothesis - there is no significant difference between the two sets of means of data
- t test will test whether we can reject/accept this hypothesis
53
What is the number of degrees of freedom
(sample size - number of data sets)
i.e. ( n1- n2 ) -2 = 18
must be considered when calculating the t-tests significance
54
How do we know if we should accept/ reject the null hypothesis
Read off table the value of 18 has 2.1 freedom i.e.
If greater then 5% value then accept if below then reject
55
What is a correlation co-efficient
used to consider the relationship between two sets of data
Spearman's rank correlation tells us whether the two sets of data are correlated or not
56
How to do the spearman's rank correlation
D- difference between the values
state null hypothesis
if under critical value then no correlation
57
What is adaption
a characteristic that enhances survival in a habitat
58
What will a well adapted organism be able to do
- find enough food to photosynthesise well
- find enough water
-gather enough nutrients
-defend itself against predators and disease
-survive physical conditions of environment
- respond to changes in environment
- have sufficient energy to allow reproduction
59
What are the different ways an organism can adapt
anatomical/ behavioural/ physiological
60
How is Marram Grass adapted
It is adapted to living on sand dunes where there is little water available so adapted to take up as much water as possible
61
What does anatomical mean
structural features that enhances organisms survival
62
What are the anatomical adaptions of marram grass
1) long roots
2) Roots spread over wide area
3) Leaves are curled
4) Lower epidermis is covered in hairs
5) Lower epidermis is folded to create pits in which stomata are positioned
6) Low density of stomata
7) Leaf covered in thick waxy cuticle
63
How are long roots an advantage for Marram Grass
plant to reach water deep underground
64
How are roots spread over a wide area an advantage for Marram Grass
absorb water where its available, helps stabilise sand dune
65
How are curled leaves an advantage for Marram Grass
reduces SA exposed to the wind, traps air inside against lower epidermis so moisture can build up in enclosed space
66
How is the lower epidermis covered in hairs an advantage for Marram Grass
- reduces air movement so water retained close to lower epidermis
67
How is the Lower epidermis folded to create pits in which stomata are positioned - an advantage for Marram Grass
water vapour build up in pits reduces water loss
68
How is a low density of stomata - an advantage for Marram Grass
fewer stomata means less water lost
69
How is Leaf covered in thick waxy cuticle - an advantage for Marram Grass
reduced evaporation of water from the leaf
70
What are behavioural adaptions
behaviour aspect of organism that enhances survival in habitat i.e. earthworm is blind so contracts and hides in burrow, rapid withdrawal
- marram grass curls up leaves/ covered by sand grow more quickly to reach sunlight
71
What is a physiological/ biochemical adaption
Adaption that ensures correct functioning of cell processes
72
What are the physiological adaptions of marram grass
1) ability to roll up leaves due to specialised hinge cells in lower epidermis
2)guard cells work in a similar way to open and close the stomata
3) able to survive salty conditions of the sea
4) Leaves contain many lignified cells that provide support when turgidity is lost
73
How is the ability to roll up leaves due to specialised hinge cells in lower epidermis - an advantage for Marram Grass
-Cells lose water and turgidity when water is scarce curl up leaf
- water is available hinge cells become turgid opening leaf for easier access to CO2 and photosynthesis
74
How do guard cells work in a similar way to open and close the stomata
-non turgid cells close the stomata
-turgid cells open the stomata
75
How does marram survive the salty conditions of the sea
Marram is not very salt tolerant but maintains Cell water potential lower then other plants
76
How is Leaves containing many lignified cells - an advantage for Marram Grass
provide support when turgidity is lost
-keeps leaf upright when water is not available
77
What organisms show an example of convergent evolution
Moles / marsupial moles have:
- cylindrical body
- small eyes
- strong front legs
- large claws on front legs
- short fur
-short tail
78
What is variation
the presence of differences between individuals
79
What is intraspecific variation
the variation of individuals in the same species
80
the variation of individuals in the same species
the variation of individuals in the same species
81
Continuous variation
variation where there are two extremes and a range of values in between
- most individuals are close to the mean value at the extremes number of individuals showing that is quite low
- usually regulated by more than one gene and can be influenced by the environment in which the organism lives
e.g. height, length of a leaf, length of stalk
82
Discontinuous variation
where there are distinct categories and nothing in between
- may be evenly distributed or more then one type in one category than the others
- regulated by a single gene and not influenced by environmental factors
e.g. gender/ human blood groups
83
What are the two causes of variation
genetic and environmental
84
What is inherited/genetic variation
genes we inherit from parents have different combinations of alleles in each living organism
85
What is environmental variation
environment affects characteristics
i.e. Hawthorne tree constantly cut will become more bushy and stop growing as much
86
What are combined effects
Genetic and environmental variation being connected to perform variation
- humans have become taller as a result of a better diet
- not all our genes are active at the same time i.e. adolescence certain genes are being switched on/off
- changes in environment can affect genes that are active
87
How does natural selection work
1) In any population variation occurs as a result of mutations
2) if there are different varieties there will be competition for food/ space
3) selection pressure is exerted on the environment
4) Organisms most adapted to environment will survive as they have the most advantageous alleles
5) They reproduce and pass on genetic mutations to offspring
6) Over time this could give rise to a new species
88
What wont be passed onto offspring
Variation due to environmental factors such as a scar
89
Is evolution still happening today
Yes - whenever a species or group of organisms are placed under a new selection pressure (use of antibiotics/pesticides) different characteristics will be selected evolution will occur = most obvious in organisms with a short life cycle
90
How do bacteria develop resistance to antibiotics
1) mutation causes bacterium to develop that has resistance to a particular antibiotic - this causes variation in a population
2) mutation will give an advantageous allele to bacterium that allows it to develop resistance to the antibiotics and survive under a selection pressure
3) Resistant bacterium will survive, whilst those without advantageous allele will not, and pass on advantageous allele to next generation
4) This creates a new strain of bacterium resistant to antibiotics
91
Why has antibiotic resistance occurred
Because of the overuse of antibiotics in humans/ agriculture and people not taking the full course of antibiotics
92
What are the problems with antibiotics developing resistance to insecticides
Insecticide is designed to kill pests and exerts a strong selection pressure
- if individual has genetic mutation may survive and become more resistant as has advantageous allele
- Can cause problems in the food chain as when insect is eaten causes predator to receive more concentrated does of insecticide
-occurred with DDT insecticide causing thinning of eggs in bald eagle population
93
What happens if you don't take the full course of antibiotics
Resistant bacteria with advantageous alleles will survive selection pressure and reproduce in the blood creating a new strain resistant to the antibiotics
- some doctors now prescribe multiple antibiotics to reduce the chances of survival
94
How to selectively breed
1)cross / breed, with disease resistant variety 2)method to test offspring for disease resistance ; select , best offspring / offspring with resistance ;
3)(inter)breed, offspring with resistance / best offspring ;
4) (continue process) for (many) generations ;
5) idea of avoid breeding, closely related / AW , individuals to preserve genetic diversity ;
6) ora (regularly back) cross with, wild variety ; idea of preserving rare varieties in case they are needed in the future ;
95
Why might one island have more variation then another
Diff islands have diff selection pressures on the environment
96
How is DNA easily replicated
-Double stranded
-Each strand acts as a template
-Hydrogen bonds easily broken between bases
-Complementary base pairing
-purine (only able to) bind to pyrimidine ; (due to) different sizes of purines and pyrimidines
- hydrogen bonding different between A & T and C & G or 3 H bonds between C & G and 2 H bonds between A & T ;
97
What is it when a new species becomes known
Speciation
