classification and evolution Flashcards
(46 cards)
1
Q
what are the 7 taxonomic groups
A
kingdom, phylum, class, order, family, genus and species
2
Q
who first proposed heirarchical classification
A
Carl Linnaeus
3
Q
why do scientisits classify organisms (3)
A
- to identify species
- to predict characteristics
- to find evolutionary links -species in the same group probably share characteristics because they have evolved from a common ancestor
4
Q
what are the three domains
A
- Archaea
- Bacteria
- Eukarya
5
Q
how do you name a species
A
binomial system
first part is the genus and has a capital letter
second part is the species and has a lower case letter
name are always written in italics (underlined if hand written)
6
Q
what are the five kingdoms and examples
A
Prokaryotae - bacteria
Protoctista - algae
Fungi - mushroom, yeast
Plantae - ferns, moss, flowering plants
Amimalia - fish, reptiles, birds, mammals
7
Q
what is phylogeny
A
- the study of the evoluntionary history of groups of organisms
- it tells use who’s related to whom and how closely related they are
- e.g. on a phylogenetic tree
8
Q
how did early classification systems work
A
only used observable features to place organisms into groups
9
Q
features of a prokaryotae
A
- unicellular
- no nucleus or other membrane-bound organelles - a ring of ‘naked’ DNA
- no visible feeding mechanism - nutrients are absorbed through the cell wall or produced internally by photosynthesis
10
Q
features of a protoctista
A
- (mainly) unicellular
- a nucleus and other membrane-bound organelles
- some have chloroplasts
- nutrients are acquired by photosynthesis, ingestion of other organisms, or both - some are parasitic
11
Q
features of a fungi
A
- unicellular or multicellular
- a nucleus and other membrane-bound organelles and a cell wall mainly composed of chitin
- no chloroplasts
- no mechanisms for locomotion
- nutrients are acquired by absorption - mainly from decaying material
- cells walls made from chitin
- reproduction by spores
12
Q
features of plantae
A
- multicellular
- a nucleus and other membrane-bound organelles and a cell wall mainly composed of cellulose
- all contain chlorophyll
- most don’t move
- nutrients are acquired by photosynthesis - they are autotrophic feeders
- store food and starch
13
Q
features of animalia
A
- multicellular
- a nucleus and other membrane bound organelles (no cell walls)
- no chloroplasts
- move
14
Q
advantages of phylogenetic classification
A
- confirms the classification groups are correct
- produces a continuous tree whereas classification requires discrete taxonomical groups
- Linnaean classification can be misleading as it implies different groups within the same rank are equivalent
15
Q
what was Darwins book called
A
on the origin of species
- the theory of evolution by natural selection
16
Q
evidence for evolution
A
- palaeontology - the study of fossils and the fossil record
- comparative anatomy - the study of similarities and differences between organisms anatomy
- comparative biochemistry - similarities and differences between the chemical makeup of organisms
17
Q
evidence provided by the fossil record
A
- ## fossils of the simplest organisms such as bacteria are found in the oldest rocks whilst fossils of more complex organisms such as vertebrates are found in more recent rocks
18
Q
what is a homologous structure
A
a structure that appears superficially different (and may perform different functions) in different organisms, but have the same underlying structure
19
Q
what are the two causes of variation
A
- an organisms genetic material (genetic variation)
- the environment in which the organism lives (environmental variation)
20
Q
what is discontinuous variation
A
a characteristic that can only result in certian values is said to show discontinuous variation
there can be no inbetween values
e.g. an animal’s sex
21
Q
what is continuous variation
A
- a characteristic that can take any value within a range is said to show continuous variation
- not controlled by a single gene but a number of genes
22
Q
when would you use Spearmans rnak
A
to work our whether there’s a correlation between a genetic or environmental factor and variation in a particular characteristic
23
Q
3 types of adaption
A
- behavioural adaptions
- physiological adaptions
- anatomical adaptions
24
Q
what are behavioural adaptions
A
ways that an organism acts that increase its chance of survival
e.g. scorpians dance before mating
possums sometimes play dead
25
what are physiological adaptions
processes inside an organism's body that increases its chance of survival
e.g. brown bears hibernate (lower their metabolism)
some bacteria produce antibiotics - kill other species of bacteria
26
what are anatomical adaptions
structural features of an organisms body that icrease its chance of survival
e.g.
otters have a streamlined shape - easier to glide through water
whales have a thick layer of blubber - helps them stay warm in the cold sea
27
explain natural selection
- variation within a population in their phenotypes, caused by mutations
- selection pressures (environmental factors such as predators, disease and competition) create a struggle for survival
- individuals with better adaptions are more likely to survive
- reproduce and pass on their advantageous alleles to their offspring
- overtime, allele frequency increases so the proportion of the population possessing the advantageous adaptions increase
- over generations this leads to evolution as the favourable adaptions become more common in the population
28
what is a students t test used for
to compare the mean values of two sets of data
data collected must be normally distributed and enough data should be collected to calculate a reliable mean
29
what are selection pressures
factors that affect the organisms chances of survival or reproductive success
30
how does drug resistance arise
- within a bacterial populaiton, there is variation caused by mutations
- a chance mutation might cause some bacteria to become resistant to an antibiotic
- when the population is treated with this antibiotic, the resistance bacteria don't die
- this means the resistance bacteria can continue to reproduce with less competition from the non-resistance bacteria, which are now dead
- therefore the genes for antibiotic resistance are passed on with a much greater frequency to the next generation
- overtime, the whole population becomes antibiotic resistance
31
what is genetic drift
random changes in allele frequency which has a greater effect on a smaller population
32
name and explain the two types of genetic drift
founder effect - the reduction in genetic variation when a small subsect of a large population is used to establish a new colony
bottle neck effect - the reduction in genetic variation and population size to to a chance event, e.g. a catastrophic environmental event
33
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what is artifical selection
humans choose organisms with desirable traits and selectively breed them together to enhance the expression of these desirable traits over time and over many generation s
34
what is selective breeding
- the population shows **phenotypic variation** (individuals with different phenotypes)
- a breeder selects an individual with the desired phenotype
- another individual with the desired phenotype is selected. the two selected individuals **should not be closely related to each other**
- the two selected individuals are bred together
- the offspring produced reach maturity and are tested for the desirable trait. those that display the desired phenotype are selected for further breeding
- the process continues for many generations: the best individuals from the offspring are chosen for breeding until all offspring display the desirable trait
35
what are problems with selective breeding
- can lead to inbreeding which occurs when only the 'best' animals or plants are bred together <-- this results in a **reduction in the gene pool** which is a reduction in the number of alleles in a population <-- **inbreeding depression**
- increased chance of organisms inheriting **harmful genetic defects**
- more vulnerable to **new diseases**
- ethically questionable - as some intensive artificial selection processes have resulted in conditions and diseases that are extremely damaging or deleterious
36
what are the 3 domains that Carl Woese suggested
- Eukarya
- bacteria
- Archaea
37
what is genetic isolation
- when does it occur
- when two poulations of the same species become reproductively isolated they can eventually become geneticallly isolated
-> if the two populations are no longer reproducing then they don't **interchange genes** in production of offspring
-> changes that occur in the allele frequencies of each group are not shared, so they evolve independently of each other, which can lead to the formation of the two populatoins that are no longer successfully able to interbreed
38
what is speciation
when the genetic differences of two populations of the same species lead to an ability of members of the populations to interbreed and produce fertile offspring
39
two types of speciation
- allopatric
- sympatric
40
what is allopatric speciation
- occurs as a result of a geographical isolation
- populations of a species are separated by a geographical barrier (natural e.g. river or man-made e.g. motorway)
- this creates two populations of the same species who are reproductively separated from each other so no genetic exchange occurs between them
- if there are sufficient selection pressures to change gene pools (and allele frequency) then eventually both populations diverge and form separate species
-
41
what is sympatric speciation
- takes place with no geographical barrier
- a group of the same species could be living in the same palce but in order for specation to take place there must exist two populations within that group and **no gene flow** occurs between them
- someonething has to separate two populations
- either **ecological** or **behavioural** separation
- ecological separation = populations are separated because they live in different environments within the same area
- behavioural separation = populations are separated because they have different behaviours
42
examples of animals that are selectively bred
- cows, goats and sheep that produce a **higher yield** of milk or meat
- chickens that lay large eggs
- domestic dogs that have a gentle nature
- sheep with good quality wool
- horses with fine feature and a very fast pace
43
examples of plants that might be selectively breed
- disease resistance in food crops
- increased crop yield
- hardiness to weather conditions
- better tasting fruits
- large or unusual flowers
44
what is interspecific variation
variation between different species
45
what is intraspecific varitiation
variation within a species
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