Module 4- classification and evolution Flashcards

1
Q

What is taxonomy?

A

identifying, naming and sorting organisms into groups

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2
Q

What are taxa?

A

groups where closely related organisms are put into

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3
Q

What is the phylogeny of organisms?

A

evolutionary relationships that helps determine which taxa an organism is part of

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4
Q

Name the taxas

A

domain, kingdom, phylum, class, order, family, genus, species

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5
Q

Define species

A

group of organisms that is able to reproduce to produce fertile offspring

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6
Q

Name an describe each kingdom

A

animalia- largest kingdom with over 1 mil species, multicellular, has nucleus and other membrane bound organelles, no cell walls or chloroplast,moves with the aid of cilia/flagella/contractile proteins, nutrients are acquired by ingestion, food is stored as glycogen

plantae-2nd largest kingdom, multicellular, has a nucleus and other memrane bound organelles, cell wall composed of cellulose, all contain chlorophyll, most don’t move, nutrients are acquired by photosynthesis, store food as starch, 250000 species

protoctista- mainly unicellular, a nucleus and other membrane bound organelles, some have chloroplasts, some are sessile but others move by cilia/flagella/amoeboid mechanisms, nutrients are acquired by photosynthesis (autotrophic feeders) and ingestion of other organisms (heterotrophic organisms)

fungi- can be unicellular or multicellular, has a nucleus and other membrane bound organelles, cell wall mainly composed of chitin, no chloroplasts or chlorophyll, no mechanism for locomotion, nutrients are acquired by absorption mainly from decaying material (saprophytic feeders), most store their food as glycogen

prokaryotae- unicellular, no nucleus or other membrane bound organelles, no visible feeding mechanism, nutrients are absorbed through the cell wall or produced internally by photosynthesis

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7
Q

Name the 3 different domains

A

archaea, bacteria, eukarya

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8
Q

Who was the first to propose the classification system?

A

Carl Linnaeus

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9
Q

Why do scientists classify organisms?

A

to easily identify species, to predict characteristics and to find evolutionary links through common ancestors

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10
Q

Why are mules infertile?

A

as their cells contain an odd number of chromosomes which means meiosis and gamete production can’t take place correctly as all chromosomes must pair up

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11
Q

What is the classification of humans?

A

D= eukarya
p= chordata
c=mammalia
o=primates
f=hominidae
g=homo
s=sapiens

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12
Q

How do you write the binomial name?

A

consists of genus and species of an organism
-must be put in itallics if typed and underlined if written

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13
Q

What have been the recent changes to classification systems?

A

-originally classification systems were based on observable characteristics/features
-through the study of genetics and other bio molecules scientists are now able to study evolutionary relationships between organisms
-when organisms evolve their DNA changes
-DNA determines the proteins that are made which in turn determines the organisms characteristics

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14
Q

What is the current classification system used by scientists?

A

3 domain system

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15
Q

who and when was the 3 domain system proposed by?

A

Carl Woese in 1977

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16
Q

How does the 3 domain system group organisms?

A

using differences in the sequences of nucleotides in the cells ribosomal RNA (rRNA) as well as the cells membrane lipid structure and their sensitivity to antibiotics

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17
Q

Describe each of the 3 domains

A

eukarya- have 80S ribosomes, organisms possessing complex sub-cellular structures
archaea- have 70S ribosomes, primitive bacteria
bacteria- have 70S ribosomes, true bacteria

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18
Q

What is a phylogenetic tree used for and what do they show?

A

-represent evolutionary relationships between organisms
-the point organisms join together is the common ancestor
-shows how different species have evolved from a common ancestor

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19
Q

Where has much of the evidence for phylogenetic trees come from?

A

fossils

20
Q

How are phlogenetic trees produced?

A

by comparing species genetic make up and physical characteristics

21
Q

What are 3 advantages of phylogenetic trees?

A

-can be done without reference to linnaean classification
-provides a continuous tree whereas classification requires discrete taxinomial groups
-scientists are not required to put organisms into specific groups that they don’t quite fit into

22
Q

What did Darwin observe and conclude?

A

-finches on the Galapogos islands all had different shaped beaks and claws
-he realised this was due to the types of food present on different islands
-the birds with the most well suited beaks to the food on their island were more likely to survive longer and reproduce passing on this characteristic
-overtime all the birds on the island will share the same beak

23
Q

What did Darwin do when he came back?

A

-sent specimens back to the UK for other scientists to preserve and classify which enabled them to see first hand the links between characteristics within organisms that Darwin had not
-carried out an experimental breeding of pigeons to gain direct evidence that his ideas may work
-Darwin and Wallace presented their ideas of evolution by natural selection together

24
Q

Describe the process of natural selection

A

1)random mutation occurs- in the gene sequence of DNA which can arise spontaneously. new mutations can result in new alleles of a gene

2)variation in mutations- by chance some mutations might confer a beneficial trait. an individual with a beneficial mutation will be more likely to survive and reproduce than an individual without the mutation

3)inheritance- when an individual with an advantageous mutation reproduces, the characteristic is inherited by their offspring

4)change in allele frequency- individuals in the next generation who have the advantageous mutation are also more likely to reproduce and pass on the allele. over many generations the allele will increase in frequency in the population (evolution)

25
Q

Describe how fossils provide traces of evolution

A

-fossils are remains or traces of ancient life
-are found in rocks that have been preserved by natural processes
-show gradual changes in organisms over vast periods in time
-different layers correspond to different ecological eras
-not all organisms leave behind a fossil when they die which is why their are huge gaps in fossil records as they are all soft bodied and decompose quick
-allow relationships between extinct and living organisms to be investigates

26
Q

How does DNA provide evidence for evolution?

A

-genomes of different species can be sequenced and compared to see how similar they are to each other
-the more similar the genomes are the more closely related they are
-in eukaryotes we can also sequence mitochondrial DNA which has been used to examine human evolutionary relationships through the maternal line

27
Q

How is molecular evidence used in evolution?

A

-some proteins like cytochrome c (used in respiration) are highly conserved across organisms
-by looking at small changes in highly conserved proteins, we can work out relatedness of different taxa and at which point they last shared a common ancestor
-look at the order of amino acids in a protein
-the number of differences that exist are plotted against the rate the molecule goes under neutral base pair substitutions

28
Q

What is intraspecific variation?

A

variation within species
individuals in the same species have different genotypes (unless they are clones) and this is what causes intraspecific variation

29
Q

What is interspecific variation?

A

variation between species
-tends to include characteristic variation which are enough to make one species different from another

30
Q

What is continuous variation?

A

-describes and graphed using a scale
-where values are consecutive within a range
-normal distribution shows most individuals close to a mean value
-characteristics that show continuous variation are usually controlled for by more than 1 gene and there may also be environmental interactions affecting phenotypes
-e.g height

31
Q

What is discontinuous variation?

A

-described and graphed using discrete categories with no intermediate values
-characteristics showing discontinuous variation are often controlled by one polymorphic gene with little environmental effect e.g blood type

32
Q

Name and describe 3 genetic causes of variation

A

-mutations-changes in the DNA sequence and therefore to genes can cause changes in the proteins that are coded for. if a mutation occurs in gametes it may be passed onto offspring however if the mutation happens in a body cell only the individual will be affected

-meiosis-gametes are produced by meiosis, each gamete receives half the genetic content of a parent cell. independent assortment and crossing over leads to the gametes of an individual showing variation

-alleles- genes have different alleles so with a gene for a particular characteristic different alleles produce different affects

33
Q

Name and describe 3 environmental causes of variation

A

-length of sunlight hours affects growth of a plant and the amount of photosynthesis that takes place

-presence of a scar on your body which would’ve occurred through an accident or a disease and won’t have any genetic origin

-insufficient nutrients for a plant and animal can mean stunted growth, fragility and loss of colour

34
Q

What is expected of a normal distribution curve?

A

-usually produce a bell shaped curve
-mean, median and mode are the same
-symmetrical about the mean
- most values lie close to the mean value (number of individuals at extremes are low)
-68% of values are within 1 SD of the mean
-95% of values are within 2 SD of the mean, 99.7% are within 3 SD of the mean

35
Q

What does standard deviation measure?

A

how spread the data is
high SD= high spread of data

36
Q

What does a T test measure?

A

-compares mean of data values within 2 populations which must be normally distributed

37
Q

What does a spearmans rank correlation measure?

A

considers the relationship between 2 sets of data
positive relationship= as one increases so does the other

38
Q

What are adaptations?

A

characteristics that help increase an organisms chance of survival and reproduction in its environment

39
Q

What are anatomical adaptations?

A

-physical structures that have evolved to increase the chance of survival
-walruses have a thick layer of blubber that insulates them and helps prevent heat loss

40
Q

What is convergent evolution?

A

where some organisms show similarities in their anatomy even though they aren’t closely related as features evolve independently where the selection pressure on those species are similar e.g marsupial mole and placental mole

41
Q

What are physiological adaptations?

A

-processes within the body that have evolved to increase the chance of survival e.g mammals shiver in cold temperatures to keep body heat at an optimum

42
Q

What are behavioural adaptations?

A

actions that have evolved to increase the chance of survival. they can be learnt or inherited. e.g cheetahs have evolved to stalk their prey

43
Q

What are 2 implications of evolution to humans?

A

antibiotic resistance and pesticides resistance

44
Q

Describe antibiotic resistance and how it affects humans

A

-within a population of bacteria some will have random mutations which are resistant to antibiotics and so survive whilst the non resistant bacteria die
-the resistant bacteria can reproduce rapidly because their competition has been destroyed by the antibiotic
-when the resistant bacteria reproduce by mitosis they produce genetically identical copies
-this puts a strain on health care systems

45
Q

Describe pesticide resistance

A

-pesticides are sprayed onto agricultural land to control the population sizes of pests that are reducing the yield of their crops
-harmful insects can evolve to become resistant to these pesticides
-losing pesticides as a form of pest control would decrease yields farmers can attain