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snab biology > Topic 4 > Flashcards

Topic 4 Flashcards

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AP® Biology flashcards
1
Q

biodiversity

A

the variety of species or organisms in an area

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2
Q

species

A
  • a group of organisms with similar morphology, physiology, and behaviour
  • can interbreed to produce fertile offspring
  • reproductively isolated from other species
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3
Q

Habitat

A
  • A place within an ecosystem where a community of organisms are found
  • characterised by physical conditions and species of organisms present
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4
Q

population

A
  • a group of organisms
  • all same species
  • all live together in a particular habitat
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5
Q

community

A

the total of all populations living together in a particular habitat

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6
Q

Low biodiversity

A
  • is not necessarily a cause for concern
  • the artic and antarctic naturally have low biodiversity compared to a tropical rain forest
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7
Q

Loss of biodiversity

A
  • is a cause for concern
  • ecosystems rely on the interdependence of all organisms to maintain stability
  • can cause irreversible damage
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8
Q

species richness

A
  • no. of species present in a given habitat
  • takes no account of population size
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9
Q

species evenness

A
  • how close the no. of each species in an environment
  • high species evenness = similar no. of each species
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10
Q

species diversity

A
  • a measure of how many different species are present in an area
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11
Q

genetic diversity

A
  • a measure of how many variations there are in the gene pool of individuals of a particular species
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12
Q

habitat diversity

A
  • a measure of how many different habitats in an area
  • including biotic and abiotic factors
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13
Q

genetic diversity - phenotype

A
  • different alleles code for different versions of the same characteristic
  • by looking at the different phenotypes in a species we can get an idea of the different alleles
  • the larger the no. of different phenotypes the greater the genetic diversity
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14
Q

genetic diversity - genotype

A
  • measure the no. of different alleles a species has for one characteristic to see how genetically diverse the species is
  • the larger the no. of different alleles the greater the genetic diversity
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15
Q

heterozygosity index

A

number of heterozygotes/no. of individuals in the population

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16
Q

niche

A

the way an organism exploits (uses) it’s environment

  • interactions with other living things: eats/eaten by
  • interactions with non-living environments - shelter site
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17
Q

competition

A
  • when 2 or more individuals strive to obtain the same resources when they are in short supply
  • the more similar the two individuals are, the more intense the competition
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18
Q

anatomical adaptations

A

adaptations that can be observed or seen when an organism is dissected

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19
Q

behavioural adaptations

A

actions by the organism which help them to survive or reproduce

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20
Q

physiological adaptations

A

internal workings within an organism which help it to survive/reproduce

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21
Q

adaption

A

a characteristic of an organism which improves its chances of surviving/reproducing

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22
Q

selection pressure

A
  • such as predation, disease and competition - creates a struggle for survival
  • anything that affects an animals chance of survival or reproduction
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23
Q

endemism

A

when a species evolves in isolation and is only found in one part of the world

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24
Q

genetic drift

A

when the frequency of an allele varies over many generations - affects smaller populations more

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25
Q

gene pools

A

consist of all of the alleles of all the genes present in a population

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26
Q

Simpson’s index of diversity symbols
N =
n =
D =

A 
N = total no. of organisms of all species 
n = total no. of organisms of a particular species 
D = probability that two randomly selected individuals will belong to the same species
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27
Q

Hardy-Weinberg equation symbols
p =
q =
p^2 =
q^2 =
2pq =

A 
p = dominant 
q = recessive 
p^2 = homozygous dominant genotype 
q^2 = homozygous recessive genotype 
2pq = heterozygous genotype
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28
Q

Hardy-Weinberg equation meanings
p+q=1 ?
p^2+2pq+q^2=1 ?

A 
p+q=1 = frequency of all alleles 
p^2+2pq+q^2=1 = frequency of all genotypes
29
Q

speciation

A
  • the development of a new species
  • occur when populations of the same species become reproductively isolated
  • can be due to:
  • seasonal changes: different mating seasons
  • Mechanical changes: changes in genitalia prevent successful mating
  • Behavioural changes: different courtship rituals
  • geographical isolation
30
Q

Geographical isolation

A
  • can lead to speciation
  • when a physical barrier divides population of a species
  • flood, volcanic eruptions and earthquakes
  • different condition and therefore selection pressures can cause speciation
  • natural selection - different alleles may be more advantageous on one side than the other
  • mutations will only be passed on in one of the populations
31
Q

Taxonomy

A

science of classification

32
Q

classification

A
  • eight levels of groups
  • domain, kingdom, phylum, class, order, family, genus, species
  • naming and organising organisms based off of similarities and differences

DEAR KING PHILIP CAME OVER FOR GOOD SOUP

33
Q

5 Kingdoms

A

Prokaryotae e.g. bacteria
Protocista e.g. algae
Fungu e.g. mushrooms
Plantae e.g. mosses
Animalia e.g. mammals

  • based on general features
34
Q

3 Domains

A
  • based on molecular phylogeny: evolutionary history, looks at DNA to see how closely related species are

Eukaryota
Bacteria
Archaea

  • Prokaryote was split into bacteria and archaea because molecular phylogeny suggested that they are more distantly related than originally thought
35
Q

The work of seedbanks involves

A
  • conserve genetic diversity
  • creating the cool, dry conditions required for storage
  • allowing seeds to be stored for a long time
  • testing seeds for viability –> seeds are planted, grown and new seeds are harvested and put back into storage
36
Q

advantages of seedbanks

A
  • cheaper than storing fully grown plants
  • large numbers can be stored in less space
  • less labour is required to look after seeds than plants
  • seeds can be stored anywhere as long as conditions are cool and dry whereas plants need the conditions from their original habitat
37
Q

disadvantages of seed banks

A
  • testing the seeds for viability can be time-consuming and expensive
  • too expensive to store all types of seeds and regularly test each for viability
  • it is difficult to collect seeds from plants that only grow in remote locations
38
Q

captive breeding programmes

A
  • breed animals in controlled environments
  • for species that are endangered or extinct in the wild they can be bred in captivity to increase their numbers
39
Q

disadvantages of captive breeding programmes

A
  • animals sometimes have problems breeding outside of their natural habitat
  • cruel to keep animals in captivity
40
Q

reintroduction into the wild

A
  • the reintroduction of seeds from seedbanks or animals from captive breeding programmes can increase their numbers in the wild
  • can also help animals who rely on these animals or plants for food or part of their habitat
  • restoration of plants and animals also contributes to restoring lost habitats e.g. rainforests that have been cut down
41
Q

disadvantages of reintroduction to the wild

A
  • can introduce new diseases
  • animals may have trouble behaving as they would if they had been raised in the wild –> will have problems finding food or communicating with wild members of their species
42
Q

seedbanks contribution to scientific research

A
  • allows the study of how to successfully grow plants from seeds –> useful for reintroduction
  • can grow endangered plants from seeds to use for medical research or new crops –> they don’t need to be removed from their environment
  • limits the study to a small inbred population - research may not represent wild population
43
Q

zoos contribution to scientific research

A
  • increases knowledge of behaviour, physiology and nutritional needs of animals - contributes to conservation efforts in the wild
  • captive animals may act differently to wild animals
44
Q

xylem function

A
  • transport water and mineral ions up the plant
  • provide support
45
Q

xylem structure

A
  • long, tube-like structures formed from dead cells joined end to end
  • hollow lumen and no end walls
  • uninterrupted tube allows water and mineral ions to move through the middle easily
  • walls are strengthened by lignin - helps support the plant
  • water and mineral ions move into and out of the pits where there is no lignin
46
Q

sclerenchyma fibres function

A
  • provide support
47
Q

sclerenchyma fibres structure

A
  • bundles of dead cells that run vertically up the stem
  • hollow lumen and have end walls
  • wall thickened with lignin
  • no pits
  • contain lots of cellulose
48
Q

phloem function

A
  • transport organic solutes from where they’re made to where they’re needed
  • this is known as translocation
49
Q

phloem structure

A
  • cells arranged in tubes
  • sieve tube elements: live cells joined end to end to form sieve tubes
  • sieve part are the end walls which have lots of holes to allow solutes to pass through
  • sieve tubes have no nucleus so require a companion cell to survive
  • companion cells carry out the living functions for both themselves and their sieve cells
50
Q

vascular bundles

A
  • in the stem xylem vessels and phloem tissue group together
  • sclerenchyma fibres are also there
  • from outside to inside:
    sclerenchyma fibres –> phloem –> xylem
51
Q

starch: amylose

A
  • long, unbranched alpha glucose
  • coiled structure = compact so good storage molecule (more in small space)
  • insoluble - doesn’t swell through osmosis
52
Q

starch: amylopectin

A
  • long, branched alpha glucose
  • good for energy - branches allow enzymes to break down glycosidic bonds easily so glucose can be released quickly
  • insoluble - doesn’t swell through osmosis
53
Q

starch and plants

A
  • cells get energy from glucose
  • plants store excess glucose as starch - when they need more energy it breaks down starch and releases it as glucose
54
Q

cellulose

A
  • long, unbranched beta glucose
  • glycosidic bonds are straight so the chains are straight
  • between 50 and 80 cellulose chains are linked together by hydrogen bonds to form microfibrils
  • these strong threads mean that cellulose provide structural support for cells
55
Q

Why plant fibres are strong: arrangement of microfibrils

A
  • the cells wall contains microfibrils in a net-like arrangement
  • their strength and arrangement gives the plant fibres strength
56
Q

Why plant fibres are strong: secondary thickening

A
  • when structural plant cells such as sclerenchyma and xylem have finished growing they produce a secondary cell wall between the cell wall and the cell membrane
  • the secondary cell wall is thicker and contains more lignin than the normal cell wall
  • this growth is called secondary thickening, it makes plant fibres even stronger
57
Q

sustainability

A
  • using resources in a way that meets the needs of the current generation without using it up for future generation
  • in order to make something sustainably you must use renewable resources
58
Q

renewable resources

A
  • can be used indefinitely without running out
  • e.g. plants are a renewable resource because harvested plants can be regrown so there is enough for future generations
  • e.g. 2 fossil fuels are a finite resource and are unrenewable - once they’re all used up there is no more
59
Q

Plant Fibres sustainability

A
  • ropes and fabrics can be made from plastic (oil) but also from plant fibres
  • this is more sustainable since fewer fossil fuels are sued up and crops can be regrown for future generations
  • plants are biodegradable unlike most oil-based plastics
  • plants are easier to grow and process than extracting and processing oil –> cheaper
60
Q

Starch sustainability

A
  • plastics can be made from oil but also starch: bioplastics
  • less fossil fuel is used up and crops from which the starch came from can be regrown
  • vehicle fuel is also made from oil but can lose be made from starch: biofuel
  • less fossil fuel is used up and crops from which the starch came from can be regrown
61
Q

plants need water for…

A

… photosynthesis, to transport minerals, to maintain structural rigidity and to regulate temperature

62
Q

plants need magnesium ions for…

A

… the production of chlorophyll - the pigment needed for phtosynthesis

63
Q

plants need nitrate ions for…

A

… the production of DNA, proteins (including enzymes) and chlorophyll

They are required for plant growth, fruit and seed production

64
Q

plants need calcium ions for…

A

… plant growth

65
Q

William Withering: Drug testing in the past

A
  • chance observation that digitalis could treat dropsy
  • too much = poison
  • too little = no effect
  • trial and error until he found the right amount
66
Q

Modern Drug testing

A
  • tested on cells in the lab
  • Computer models may also be used to simulate the metabolic pathways that may be taken by the drug
  • tested on animals to see the effect on a whole organism
  • all new medicines in the UK have to have tests on 2 different animals by law
  • Efficiency, toxicity and dosage are tested at this stage

Then human trials:

Phase 1: testing on a small group of healthy individuals –> find out dosage, side effects and how the body reacts

Phase 2: larger group of this time patients –> find out effectiveness of drug

Phase 3: tested on hundreds of patients –> compared to existing drugs –> patients are randomly split into two groups: existing treatment vs new treatment

67
Q

Placebos

A

an inactive substance that looks exactly like the drug but does not contain the active ingredient so does not do anything

68
Q

Double-Blind trial

A
  • neither the doctor nor the patient knows if the patient is getting the active drug or the placebo (or old drug)
  • REDUCES BIAS

snab biology (11 decks)

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