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Biology AS > Chao 6 > Flashcards

Chao 6 Flashcards

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1
Q

What is the taxonomic hierarchy used to classify species?

A

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

Drunk king Phillip came over good soup

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2
Q

What is the binomial naming system and why is it used?

A

A two-name system (Genus species) that ensures a universal, standardized classification of organisms.

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3
Q

What are the five kingdoms used to classify organisms?

A

Prokaryotae, Protoctista, Fungi, Plantae, Animalia.

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4
Q

What are the three domains of life and why were they introduced?

A

Bacteria, Archaea, and Eukarya—introduced due to genetic and molecular evidence showing major differences in prokaryotes.

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5
Q

What is phylogeny?

A

The study of evolutionary relationships between organisms.

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6
Q

What are the main pieces of evidence supporting evolution?

A

: Fossils, genomic DNA, and molecular evidence.
(characteristics are passed on to offspring in genes, The more similar the nucleotide sequence the more closely related the species are.)

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7
Q

What are the two types of variation?

A

Intraspecific (within a same species), allows natural selection to occur and interspecific (between different species).

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8
Q

What is the difference between continuous and discontinuous variation?

A

Continuous variation (e.g., height) is influenced by multiple genes, caused by genetics and the environment .represented by histograms. Different alleles have a small effect on the phenotype

Discontinuous variation (e.g., blood type) is controlled by a single gene.caused by genetic.factors represented by bar charts
Different alleles at a single gene have a large effect on the phenotype

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9
Q

What are the three types of adaptations in organisms?

A

Anatomical (structural), physiological (biochemical processes), and behavioral (actions).

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10
Q

How does natural selection lead to evolution?

A

Genetic variation + selection pressure (increase the chance of individuals with a specific (more advantageous) phenotype surviving and reproducing over others & Environmental factors)+ reproductive success = increase in advantageous traits over generation

-Random mutation can produce new alleles of a gene, leading to an increased chance of survival and increased reproductive success

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11
Q

Give an example of evolution affecting human populations.

A

Antibiotic resistance in bacteria due to natural selection.

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12
Q
A
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13
Q

What is ring rot

A

caused by bacterial pathogens

nfect the vascular tissue and prevent the transport of water, causing the plant to wilt and die

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14
Q
A
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15
Q

Viruses and examp,es

A

No cellular structure,

Tobacco Mosaic Virus (TMV), causes a distinct yellowing of the leaves which produces a mosaic pattern

Three different influenza viruses infect humans to cause the flu
Influenza A, influenza B and influenza C infect the cells that line the airways
They cause a high temperature, body aches and fatigue
Influenza A is the virus that causes the most cases of flu globally
It has a capsid that surrounds 8 single-stranded molecules of RNA

human immunodeficiency virus (HIV) infects specific cells of the immune system.

enveloped retrovirus,

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16
Q

Prptocista and examples

A

unicellular eukaryotes

causes malaria. parasite is spread by mosquitoes
Infected individuals experience fever, chills and fatigue

potato blight some fungal characteristics transmitted via spores The protist destroys potato and tomato crops leaving them completely inedible

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17
Q

Eg of fungi

A

Athletes foot is Black Sigatoka i n bananas

It spreads through the leaves of the plant, reducing its ability to photosynthesise parts of the leaf to die Eventually, the whole leaf dies

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18
Q

Endemic

A

a disease that is always present in a population (even if very low numbers)

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19
Q

Epidemic

A

there is a large increase in the number of cases in a population (an outbreak

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20
Q

Pandemic

A

an epidemic occurs on a large scale and crosses international boundaries

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21
Q

Plant Defences Against Pathogens

A

Passive defence:
-always present
-some are physical barriers that prevent pathogens from entering
-chemicals that reduce or prevent the growth of pathogens
-eg Waxy cuticle, Bark, Closed stomata

Active defence mechanisms are activated when pathogens invade
-Hypersensitivity deprives pathogens of resources
-formation of physical barriers by callose plays a major role in limiting the spread of pathogens
-eg Enzyme inhibitor

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22
Q

Hypersensitivity

A

rapid death of tissue surrounding the infection site, deprives the pathogens of host tissue, nutrients and energy

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23
Q

Blood clotting

A

break in the mucous membranes. Thrombositin -platelets trigger a chemical reaction cascade that results in the formation of fibrin, which forms a scab.

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24
Q

Animal defence mechanisms

A
  • non specific: same for all pathogen &rapid (eg:physical barrier) (eg: cell mediated response & humpral response & phagocyte )
    -specific: slower,specific to each pathogen
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25
Macrophages mode of action
initiating the specific immune response do not destroy pathogens completely; instead display the antigens of the pathogens on their surface Antigens are displayed as part of a structure called a major histocompatibility complex (MHC) So cell no w an antigen-presenting cell and can be recognised by lymphocytes
26
Structure of antibodies
-globular glycoproteins called immunoglobulins -quaternary structure, with two ‘heavy’ (long) polypeptide chains bonded by disulfide bonds to two ‘light’ (short) polypeptide chains -Each polypeptide chain has a constant region and variable region -constant region determines the mechanism used to destroy the antigens -variable regions found at the tips of the "Y” -variable region is where the antibody attaches to the antigen to form an antigen-antibody complex -end of the variable region is antigen-binding site. The sites are specific to the epitope (the part of the antigen that binds to the antibody) -The ‘hinge’ region (where the disulfide bonds join the heavy chains) gives flexibility to the antibody molecule which allows the antigen-binding site to be placed at different angles when binding to antigens
27
Define immunity
Ability of an organisms to resist infection
28
Define antigen
A protein that triggers an immune response
29
Types of immunity
**Active immunity ** when an antigen enters the body triggering a specific immune response (antibodies are produced) -antibodies produced by body. Slow for antibodies to appear/produce in blood -have memory cell -if induced by **natural** =exposure to pathogen -if induced by **artificial ** =vaccination **passive immunity ** the body is given the antibodies -if **natural**= antibodies revived from another organism (eg placenta) -if **artifical** = antibodies injected -no memory cell -immediately antibodies in blood
30
For a disease to be eradicated by vaccine, it shouldn’t…
Mutate Have a life cycle that includes other organisms Have symptoms that make it hard to diagnose or trace
31
Define classification
Grouping of organisms
32
Define Taxonomy
The study of biological classification
33
Define species
group of organisms that are able to reproduce to produce fertile offspring
34
Archaea
Slmetime known as extremophile prokaryotes no nucleus (and so are prokaryotic) No peptidoglycan in their cell walls Membrane lipids (unique) Ribosomal RNA (70s)
35
Kingdom fungi
eukaryotic cells Don’t have cilia Fungi are heterotrophs.( obtain this energy and carbon by digesting dead/decaying matter reproduce using spores that disperse onto the ground nearby
36
Kingdom plantae
multicellular eukaryotic organisms cell walls composed of cellulose Are able to differentiate into specialized cells to form tissues and organs They are autotrophs. (can synthesize their organic compounds and molecules for energy use and building biomass from inorganic compounds)
37
Kingdom animalia
multicellular eukaryotic organisms differentiate into many different specialised cell types that can form tissues and organs Have no cell walls heterotrophs, eats other plants or animals for energy and nutrients
38
Define variation
differences between living organisms
39
40
Natural selection
The process by which organisms better adapted to their environment survive and reproduce and pass on their advantageous alleles to the their offspring, whilst those less well adapted fail to do so
41
Standard Deviation
measures the spread of data around the mean value. comparing consistency between different data sets MUST GAVE MEAN
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https://cdn.savemyexams.com/cdn-cgi/image/f=auto,width=1200/https://cdn.savemyexams.com/uploads/2020/11/Calculating-Standard-Deviation.png
43
What is T test (variation)
compare the means of two sets of data determine they are significantly different or not
44
Degrees of freedom
calculated as the sample size minus one the degree of freedom is n−1 .
45
How to do T-test
1) need Null hypothesis . Eg there is no statistically significant difference between the means of sample 1 and sample 2 there is no statistically significant difference between the means of sample 1 and sample 2 2)Calculate the standard deviation for each set of data (6,1plot data,optn,3,sx) 3) Square the standard deviation and divide by n (the number of observations) in each sample, for both samples: 4) Add the values from step 3 together and take the square root: 5) Divide the difference between the two means (see step 1) with the value calculated in step 4 to get the t value 6) Calculate the degrees of freedom (v) for the whole data set: v = (n1 - 1) + (n2 - 1) 7) Look at a table that relates t values to the probability that the differences between data sets is due to chance to find where the t value for the degrees of freedom (v) calculated lies. LOOKING FOR LESS THAN 5%(0.005) 8) The greater the t value calculated (for any degree of freedom), the lower the probability of chance causing any significant difference between the two sample means: -If the t value is greater than the critical value then any difference between the means of the two data sets is said to be statistically significant & The null hypothesis can be rejected -If the t value is less than the critical value there is no significant **difference** , null hypothesis is accepted
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47
What is Convergent evolution
Shared adaptations between unrelated organisms arise due to convergent evolution occurs by natural selection
48
Fitness of Organisms
its ability to survive and pass on its alleles to offspring Organisms with higher fitness possess adaptations that make them better suited to their environment
49
Process of natural selection
Within a species, there is always variation and chance mutation Some individuals will develop a phenotype (characteristic) that gives them a survival advantage and this allows them to: -live longer -breed more -be more likely to pass their genes on Some individuals are better adapted to selection pressures than others. Those with advantageous alleles are more likely to reproduce and pass on the allele. Greater proportion of next generation inherit the allele. Allelic frequency of advantageous traits increase
50
How bacteria inherit antibiotic resistance
Vertical transmission: -Bacteria reproduce asexually by binary fission, very rapid. If one bacterium contains a mutant gene that gives it antibiotic resistance, all of its descendants will also have the antibiotic resistance. -only responsible for passing on antibiotic resistance within a single bacterial population Horizontal transmission: -Plasmids often contain antibiotic-resistant genes & frequently transferred between bacteria occurs during conjugation. -can spread antibiotic resistance within a single bacterial population, between two populations of the same species of bacteria, or occasionally between populations of different species of bacteria.
51
Define gene pool
Total information from all genes and alleles of the breeding individuals in a populations at particular time
52
What is molecular phylogeny?
Using DNA, RNA, or protein sequence comparisons to determine evolutionary relationship
53
What is adaptive radiation?
A single ancestral species evolves into several different species adapted to different environments
54
What is a cladogram?
A diagram showing evolutionary relationships based on shared characteristics or molecular data.
55
What is a clade
A group of organisms that includes an ancestor and all its descenda
56
What is meant by ‘selective breeding’?
Humans selecting organisms with desirable traits and breeding them to enhance those traits in future generations
57
What are the limitations of the fossil record?
Not all organisms fossilise • Fossils may be incomplete or destroyed • Gaps in the record
58
What are selection pressures
Environmental factors that affect an organism’s ability to survive and reproduce
59
What is stabilising selection?
Selection that favours the average phenotype and selects against extremes.
60
What is directional selection
Selection that favours one extreme phenotype, causing a shift in the population mean.
61
What is disruptive selection
Selection that favours both extremes of a phenotype and selects against the average.
62
What is speciation?
The formation of new species from an existing one due to reproductive isolation and accumulation of genetic differences.
63
What is allopatric speciation?
Speciation that occurs due to geographical isolation.
64
What is sympatric speciation
Speciation that occurs without geographical isolation, often due to behavioural or reproductive barriers.
65
What are the types of reproductive isolation?
Temporal isolation • Mechanical isolation • Behavioural isolation • Gametic isolation
66
Define genetic drift.
Random changes in allele frequency in a small population due to chance.
67
What is the founder effect?
When a new population is established by a small number of individuals, leading to reduced genetic diversity.
68
What is a genetic bottleneck
A sharp reduction in population size due to an event, reducing genetic diversity
69
What is a taxon?
A group of one or more populations of organisms seen by taxonomists to form a unit (e.g. species, genus).
70
How does molecular evidence support classification?
Similarities in DNA or amino acid sequences • More similarities indicate closer evolutionary relationships
71
What are the benefits of using DNA analysis in classification?
Objective • Can reveal evolutionary links not evident morphologically • Useful for classifying extinct or cryptic species
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Define biodiversity
The variety of living organisms in an area.
74
What are the three levels of biodiversity?
1. Habitat biodiversity – number of different habitats in an ecosystem. 2. Species biodiversity – number of species and abundance of each species. 3. Genetic biodiversity – variety of alleles within a species.
75
What is species richness?
The number of different species in an area.
76
What is species evenness?
The relative abundance of each species in an area.
77
How is species biodiversity measured?
By using both species richness and species evenness.
78
What does a low Simpson’s Index of Diversity (D) value suggest?
Low biodiversity; ecosystem is dominated by one or a few species; less stable.
79
What does a high Simpson’s Index (D) value suggest
High biodiversity; more stable ecosystem with better resilience to change.
80
Why is sampling used?
To estimate biodiversity without counting every individual.
81
What are two types of sampling?
• Random sampling – avoids bias. • Non-random sampling – includes stratified, systematic, and opportunistic.
82
Give three methods used in animal sampling
1. Pitfall traps 2. Sweep nets 3. Pooters
83
Give three methods used in plant sampling.
Quadrats 2. Transects 3. Point frames
84
Give two human activities that reduce biodiversity.
1. Deforestation 2. Agriculture (e.g. monoculture)
85
How does agriculture reduce biodiversity?
Removes habitats. • Selective breeding reduces genetic diversity. • Use of pesticides and herbicides.
86
What is climate change’s effect on biodiversity
• Alters species distribution. • Increases extinction rates. • Changes habitats.
87
What is conservation?
The maintenance of biodiversity through human action or management.
88
Difference between in situ and ex situ conservation
In situ: conservation within natural habitat (e.g. nature reserves). • Ex situ: conservation outside natural habitat (e.g. zoos, seed banks).
89
Give two advantages of in situ conservation
Maintains evolutionary adaptations. • Conserves entire habitat.
90
Give two disadvantages of ex situ conservati
May not survive reintroduction. • Doesn’t maintain natural behaviour.
91
What is the aim of CITES?
To regulate trade of endangered species to prevent extinction.
92
What does the Rio Convention on Biological Diversity aim to do?
Promote sustainable development and conservation of biodiversity.
93
What is niche
the role an organism plays within its ecosystem, encompassing its interactions with both living and non-living components

Biology AS (3 decks)

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