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Biology A level > 4.5 Species and Taxonomy > Flashcards

4.5 Species and Taxonomy Flashcards

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1
Q

What is species?

A

organsism with shared characteristics that interbreed to produce fertile offspring

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2
Q

Why doesnt the definition of species apply to single-celled orgs?

A

they are asexual = no interbreeding

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3
Q

How is interbreeding tested?

A
  • pops are isolated and interbred
  • orgs in fossil records
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4
Q

What is an example of the difficulties defining species?

A

mule = cross between a horse and a donkey
mules are sterile = infertile
mules have odd no. of chromosomes so cannot form homo pairs = no meiosis

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5
Q

Why is it difficult to distinguish different species using fossil records?

A

cant see all characteristics
difficult to test interbreeding

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6
Q

How is it difficut to distinguish a species?

A

variation within a species

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7
Q

What are courtship behaviours?

A

complex displays that help an individual attract a mate

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8
Q

What are the purposes of courtship behaviours?

A

helps individuals to recognise members of their own species
helps ensure both individuals are in the correct physiological state for breeding
forms a pair bond
synchronise mating for when the female is fertile

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9
Q

What is classification?

A

orgs are placed in groups = taxonomy

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10
Q

What are the 2 purposes of classification?

A

gives an idea of what species are related
predict characteristics of newly discovered orgs

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11
Q

What is a taxon?

A

the specific group a org is in

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12
Q

What is the 5 kingdom classification based on?

A

cell type and organisation of cells
nutrition

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13
Q

What are the 5 kingdoms?

A

Plantae
Fungi
Animalia
Protoctista
Prokaryota

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14
Q

What is the limitation of 5 kingdom classification?

A

doesnt show how diff prokaryotic bacteria are diff

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15
Q

What is hierachal classification?

A

large groups sub-divided into smaller groups

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16
Q

How is the hierachal classification discrete?

A

no overlapp in taxons

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17
Q

What does orgs with shared taxons tell you?

A

they have more shared and similar characteristics

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18
Q

What is humans full taxons?

A

kingdom = animalia
phylum = chordates (vertebrates)
class = mammals
order = primates
family = homondids
genus = homo
species = sapien

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19
Q

What are features of the bionomial naming system?

A

unambiguous = not open to interpretation
universal = understood by all
uses latin = recognised scholary language

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20
Q

What does the bionomial naming system show?

A

evolutionary relationships

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21
Q

How do you write a biomial name?

A

Genus species
capital for genus
lower case for species
underline

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22
Q

What do phylogenetic trees show?

A

provides an idea of evolutionary relationships and shared characteristics

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23
Q

What does the end of the branch in a phylogenetic tree show?

A

species that currently exist

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24
Q

How can you tell if species are more closely related from a phylogenetic tree?

A

they share a greater proportion of lines of decent

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25
What is homologous structures?
same fundamental structure but different function
26
What is an example of homologous structures?
pentadactile limbs - includes lizard, bird, human, whale bone structure is 1-2-5 from top of arm
27
What are homologous structures evidence of?
a recent common ancestor
28
What type of evolution results in homologous structures?
divergent evolution
29
What is divergent evolution?
a process in which closely related species or populations develop different traits over time, usually due to geographic separation or different selective pressures
30
What are analogous structures?
different structures but same fundamental function
31
What is the issue with analogous structures?
they are not from a common ancestor - causes problems for classification and phylogenetics due to similar structures
32
What are examples of analogous structures?
whale, turtle, fish, penguin
33
What type of evoltion leads to analogous structures?
convergent evolution
34
What is convergent evolution?
 biological process that occurs when organisms that are not closely related evolve similar traits or behaviors
35
What are the 3 domains?
Eubacteria Archaea Eukaryota
36
Which 2 domains include Prokaryotes?
Eubacteria and Archaea
37
Which 2 domains are most closely related?
Archaea and Eukaryota
38
What kingdoms is in the Eukaryota domain?
protoctista fungi plantae animalia
39
What type of bacteria is in the Archaea domain?
extremaphiles
40
What are extremaphiles?
bacteria which can survive in very harsh conditions
41
Why is there 2 seperate domains for prokaryotes?
extremaphiles part of archaea domain have a different rRNA base sequence to prokaryotes in Eubacteria domain
42
What is a phylogenetic group?
a group of organisms classified together based on common ancestors and shared characteristics
43
What is taxonomy?
classifying orgs based on characteristics and evolutionary relationships
44
What 6 common characteristics do all organisms share?
1. all have DNA or RNA as their genetic material 2. genetic code is universal = same codon on mRNA for an aa 3. proteins are formed from the same 20 aa 4. ATP = universal molecule for energy 5. all have phospholipid membranes 6. vital physiological processes follow very similar metabolic pathways
45
What are the 3 ways of investigating evolutionary relationships?
comparision of DNA base seqeunces - genetic fingerprinting and DNA hybridisation comparision of protein and amino acid sequences immunology
46
How does comparing DNA base sequences show evolutionary relationships?
provides a reliable indicator of similarity without the problem or morphological covergence (analogous structures)
47
What are the 2 methods of comparing DNA base sequences?
genetic fingerprinting DNA hybridisation
48
What are VNTRs?
variable number tandem repeats = found in introns, long sequences of DNA bases that repeat over and over
49
How can you tell if 2 people are related by VNTRs?
more similar VNTRs = more closely related
50
What is genetic fingerprinting?
the analysis of VNTR DNA fragments used to determine genetic relationships and the genetic variabiliy within a population
51
What is done to a small DNA ample to amplify the amount of DNA?
PCR = polymerase chain reaction
52
What is DNA hybridisation?
a process in which 2 complementary DNA/RNA strands bond together to form a double-stranded molecule
53
What is the process of DNA hybridisation?
1. compares DNA base seq od two species 2. DNA from both species extracted and cut into fragments 3. fragment of 2 species are mixed together 4. complementary base seq hybridise (bond) together
54
How is comparisions of protein and amino acid seq be used to test evolutionary relationships?
1. changes in DNA base seq will alter a.a seq in a protein 2. comparisons of a.a seq of common proteins used to estimate relatedness between species
55
What is the issue with using comparison of protein amino acid sequences to find evolutionary relationships?
the number of common proteins is limited as most of the new studied use RNA or DNA sequence
56
How is immunology used to test for evolutionary relationships?
mix antigens of one species (blood plasma proteins) with specific antibodies of another so that a precipitate will form the closer the evolutionary advantage = more precipitate will form
57
What is used to work out evolutionary relationships?
homologous structures and biochemical analysis
58
Why is taxonomy known as dynamic?
diff opinions about whether morphology or genetics are more central for the basis of classification
59
How do scientists classify species based on comparing genetic characteristics?
the base sequence of DNA the base sequence of mRNA the amino acid sequences of proteins
60
What does the same genus mean in a phylogenetic classification?
same evolutionary origin and common ancestor
61
What is an advantage of having a higher species richness?
more orgs for the food web
62
What is the advantage of having more mass of carbon stored?
less CO2 in the atmosphere

Biology A level (36 decks)

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