Classification and evolution Flashcards
1
Q
What is classification?
A
The organising of living things into groups based on similarities and differences
2
Q
Why do scientists classify organisms?
A
- to identify species
- to predict characteristics
- to find evolutionary links
3
Q
What is the order of the 7 taxonomic groups?
A
Kingdom
Phylum
Class
Order
Genus
Species
4
Q
Why is universal naming using Latin important?
A
- All biologists use the same names for organisms
- so that language barriers between scientists do not affect communication/ research
5
Q
Define species
A
- a group of organisms that share particular characteristics that can interbreed to produce fertile offspring
6
Q
Who made the binomial name system and what are the features?
A
- Carl Linnaeus
- Genus then species
- Genus is capitalised, species is italicised and underlined
7
Q
What are disadvantages of this system?
A
- Used to be descriptive and based on characteristics
- common names and appearence don’t show relationships
8
Q
What are the 5 kingdoms?
A
- Prokaryotes
- protocista
- Fungi
- Plantae
- Animalia
9
Q
Describe features of the prokaryota kingdom
A
- no nucleus or membrane bound oranelles
- unicellular
- small ribosomes (70s)
- no visible feeding mechanism
10
Q
Describe features of the protocista kingdom
A
- nucleus and membrane bound organelles
- unicellular
- some have chloroplasts
- some are autotrophic (make own food), some are heterotrophic, some are parasitic
(amoeba, algae)
11
Q
Describe features of the fungi kingdom
A
- nucleus and membrane bound oranelles
- cell wall of chitin
- unicellular or multicellular
- saphrocytic (absorb nutrients from decay)
- store food as glycogen
12
Q
Describe features of the plantae kingdom
A
- eukaryotic
- multicellular
- chlorophyll
- cellulose cell wall
- autotrophic
- store food as starch
13
Q
What did carl Woese introduce?
A
- He divided prokaryotes into archaebacteria (kingdom) and eubacteria (domain)
14
Q
What are the features of the domain bacteria?
A
- 70S ribosomes
- RNA polymerase has 5 proteins
- true bacteria
15
Q
What are the features of the domain archaea?
A
- 70S ribosomes
- RNA polymerase contains between 8-10 proteins
- ancient bacteria, can live in extreme conditions
16
Q
What are the features of the domain eukaryota?
A
- 80S ribosomes
- RNA polymerase contains 12 proteins
17
Q
Summarise contributions of Darwin
A
- Observations of finches on Galapagos islands
- beaks and claws different sizes
- the design of the beak was linked to food available
18
Q
Summarise contributions of Wallace
A
- Noticed characteristics and links that Darwin didn’t
- sent ideas to Darwin for peer review, they proposed the theory of evolution through a joint presentation
- published ‘ on the origin of species’ (natural selection)
19
Q
What are the four observations Darwin made?
A
- Offspring are generally similar in appearence
- no two organisms are individual
- organisms produce a lot of offspring
- populations stay stable in size
20
Q
What conclusions did Darwin draw from his observations?
A
- Organisms that are better adapted to survive will reproduce and pass on characteristics
- over time changes can give rise to a new species
- some species struggle to survive
21
Q
Why did people not believe Darwin?
A
- Not well known
- Religion
- insufficient evidence
- couldn’t explain how characteristics were passed on
22
Q
Describe some evidence provided by the fossil record
A
- Fossils of simplest organisms are found in oldest rocks, complex organisms are found in recent rocks. Shows that simple life forms gradually evolved over a long period of time
- Fossils allow relationships between extinct and living organisms to be investigated
- by studying similarities in the anatomy of fossil organisms, scientists can show how closely related organisms have evolved from the same ancestor
23
Q
What are advantages of the fossil record?
A
- Scientists can show how cloesly related organisms evolve from the same ancestor
- allow relationships between extinct and living organisms to be investigated
24
Q
What are disadvantages of the fossil record?
A
- not complete, soft bodied organisms decompose before fossilisation
- fossils may have been destroyed by earth’s movements
25
What is a homologous structure?
- A structure that appears superficially different in different organisms but has the same underlying structure
26
What is divergent evolution?
- From a common ancestor different species have evolved with a set of adaptive features.
- Occurs when closely related species diversify to adapt to new habitats
27
What is comparitive anatomy?
The study of similarities and differences in the anatomy of different living species
28
What is comparative biochemistry?
The study of similarities and differences in the proteins and other molecules that control life processes
29
What is intraspecific variation?
Variation within a species
30
How does meiosis/ sexual reproduction lead to variation?
- crossing over
- mutations
- independent assortment
- random fertilisation of gametes
31
What are examples of environmental variation?
- light intensity
- water content in soil
32
How does an environment lead to variation in phenotype?
- Having a genotype that is not expressed in the phenotype due to interaction with the environment
33
What is convergent evolution?
Two unrelated species adapt in similar ways to their environment and look very similar
34
How is cytochrome C used to determine evolutionary links?
- Cytochrome c is a protein used in respiration
- Every organism has it but it isn't identical
- Protein made from amino acid chains, the amino acids in CC can be identified
- CC samples from two species can be compared
- If the sequences are the same they are closely related
35
How is DNA used to determine evolutionary links?
- DNA is a genetic code
- code is universal
- Changes in sequences are called mutations
- Comparison of DNA sequences provides another way to classify species
36
What is artificial classification?
- its based on only a few characteristics
- does not reflect evolutionary relationships
- provides limited info
- its stable
- Done for convenience of grouping things together
37
What is natural classification?
- uses many characteristics
- reflects evolutionary relationships
- provides useful info
- may change with advancing knowledge
- Involves detailed study of individuals in a species
38
What is continuous variation?
- Where there are two extremes and a full range of intermediate values
- Most individuals are close to the mean value
- Regulated by more than one gene and can be influenced by environment
- Histogram
39
What is discontinuous variation?
- Two or more distinct categories with no intermediate values
- members of a species may be evenly distributed
- Regulated by a single gene and not influenced by environment
- Bar chart
40
How does gene expression affect organisms?
- Not all our genes are active at any one time
- changes in the environment can affect directly which genes are active
41
What is an adaptation?
A variation in a characteristic that increases an organisms chance of survival and reproduction
42
What are anatomical adaptations?
Physical features
43
What are physiological adaptations?
Processes taking place inside an organism/ an organism's biochemistry
44
Describe adaptations of maram grass
1. Leaf is rolled longitudinally, humid inside, less water lost
2. thick waxy cuticle on the outer side of rolled leaf
3. stomata are in pits which are folded and covered by hair, reduces air movement, less loss of water vapour
4. spongy mesophyll is dense with few air spaces, less SA for evaporation
45
What are analogous structures?
They have adapted to perform the same function but have a different genetic origin
46
Briefly describe natural selection
- Advantageous alleles mean these individuals are more likely to survive and reproduce
- As they reproduce, the frequency of the AA increases as it is passed onto offspring
- mutations lead to genetic variation or new alleles over time
- selection pressures mean some individuals have an advantage over others
- more likely to reach reproductive age and breed successfully
47
How has MRSA become antibiotic resistant?
1. Bacteria reproduce rapidly and evolve in short time
2. Mutations in some S. aureus arose that produced resistance to methicilin
3. resistant individuals survived and reproduced, passing the allele for resistance onto offspring
4. the number of resistant individuals increase over time
5. eventually leading to a new reistant strain
48
Describe pesticide resistance involving Diazinon
1. Used to kill blowflies and prevent flystrike in sheep as they would lay eggs in their skin and infection
2. Blowflies developed high resistance
3. Resistant individuals survived and reproduced to pass on this characteristic
49
What is phylogeny?
- The study of the evolutionary relationships between species. It involves studying how closely different species are related.
50
What does monophyletic mean?
- Organisms that have all evolved from the same species
51
What are some physiological/ biochemical adaptations of marram?
- Ability to roll its leaf due to hinge cells in the lower epidermis
- Hinge cells lose when water is scarce which rolls leaf more tightly
- Marram is not very salt tolerant but it maintains a cell WP lower than other plants, enables it to survive in salty conditions (around sea)
- Leaves contain many lignified cells that provide support when turgidity is lost, keeps leaf upright when water is not available
