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Wjec Biology Unit 2 > 2.1 > Flashcards

2.1 Flashcards

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1
Q

Identify some sources of error when investigating the biodiversity of animals

A
  • some easier to catch than others
  • misidentification
  • recounting
  • move around
  • camouflaged
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2
Q

What is classification

A

Organisation of every living thing into groups

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3
Q

Aim of classification

A

Group organisms to reflect how closely they are related in terms of their evolutionary relationships

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4
Q

What does it mean that classification is hierarchical

A

Large groups are split into groups of decreasing size

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5
Q

What does is mean that classification is phylogenetic

A

Organisms in the same group are more closely related

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6
Q

What does it mean that classification is discrete

A

An organism cannot belong to more than one group at the same taxonomic level

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7
Q

What is a group called

A

Taxon

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8
Q

List the hierarchy of taxa

A 
Kingdom
Phyla
Classes
Orders
Families 
Genera
Species
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9
Q

What are the three domains

A

Eubacteria
Archaea
Eukarya

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10
Q

Eubacteria

A

True bacteria

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11
Q

Archaea

A

Prokaryotic but extremophiles

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12
Q

Eukarya

A

Eukaryotic organisms

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13
Q

What is an extremophile

A

Lives where environmental conditions are harsh

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14
Q

Where does the evidence for the three lineages come from

A

Studies on ribosomal RNA

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15
Q

What is a species

A

Group of organisms with similar characteristics that can interbreed to produce fertile offspring

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16
Q

Why is a hybrid sterile

A

Gametes of the two species have different chromosome numbers so chromosomes cannot pair up at start of meiosis - cant make gametes

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17
Q

What are the two parts of the binomial name of a species

A

Generic name and species name

Italicized

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18
Q

Generic name

A

Capitalised

Gives genus

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19
Q

Species name

A

Lower case

Species

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20
Q

What is a phylogenetic tree

A

Diagram that represents the evolutionary pathways leading to different species

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21
Q

What is the axis and tree branches of a phylogenetic tree

A

Axis is time

Tree branches as time moves forward

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22
Q

What does a junction represent in a phylogenetic tree

A

Common ancestor of the organism that branch from it

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23
Q

What is a clade

A

Group of branches from one common ancestor

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24
Q

What biological polymers can be used to establish relatedness and why can they be used

A

DNA, RNA or protein

They have different subunits which can be compared and number of differences counted

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25
Q

How are mutations owing to differences in biological polymers

A

They lead to differences in the amino acid sequence of proteins

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26
Q

What can gel electrophoresis fo

A

Separate fragments of DNA and proteins
Allows small fragments to move further and electrical charge causes movement of negatively charged DNA fragments to positive electrode

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27
Q

What is produced when using gel electrophoresis

A

Banding pattern that can be used to compare

28
Q

What is morphology

A

Looking at the shape and form of an organism

29
Q

What used to be the main evidence that naturalists had to classify organisms and construct phylogenetic diagrams before biochemical analysis

A

Morphology

30
Q

What is convergent evolution

A

Ancestors have adapted themselves to same environmental pressure but from different developmental origins

31
Q

What is a homologous structure

A

Structures in different species with a similar anatomical position and development origin derived from a common ancestor
Similar structure different functions
Related organisms

32
Q

Example of homologous structure

A 
Pentdactyl limb
Mammals - grasping
Birds - flight
Whales and dolphins - swimming
Moles - digging
33
Q

What is an analogous structure

A

Corresponding function and similar shape but different developmental origin
Unrelated organsims

34
Q

What is biodiversity

A

Describes the species richness and species evenness in a given area

35
Q

What is species richness

A

Number of species

36
Q

What is species evenness

A

Number of individuals of each species

37
Q

What does it mean that biodiversity varies spatially

A

Increases going from poles towards the equator

38
Q

Why does biodiversity vary spatially

A

More UV light - higher rate of mutation so more rapid evolution
More species types - more habitats and niches
More stable temperature range and water availability- more favourable conditions for survival
More species and individuals so higher competition so narrower exploitation of niches so harder to move our the area

39
Q

Factors affecting biodiversity

A

Human activity
Natural selection
Succession

40
Q

What is succession

A

Composition of a community changes over time as different species colonise

41
Q

2 ways an area can be sampled

A

Gridding or by a transect

42
Q

When is gridding used to sample

A

Two areas are to be compared

43
Q

When is a transect used when sampling

A

Gradual change in the environment

44
Q

Why is random sampling important

A

Avoids unconscious sampler bias which increases reliability of data

45
Q

How is random sampling achieved?

A

Random number tables are used to generate rand co-ordinates for a gridded area and the quadrats placed at those co-ordinates only
Sampling along transect done at fixed distance

46
Q

What are the 5 kingdoms

A 
Plantae
Animalia
Fungi
Prokaryotes
Protoctista
47
Q

Technique used to sample terrestrial animals

A

Mark-release-recapture

Lincoln index

48
Q

Method used for Lincoln index

A

Animals captured and marked and then released
Once they have had a change to reintegrate with the population the traps are reset
Pop size = no in sample 1 x no in sample 2 / no in marked sample

49
Q

Important points when using Lincoln index

A
  • animals cannot be harmed or made more visible to predators

* assume that no births/deaths/immigration/ emigration have occured

50
Q

Technique used to sample freshwater invertebrates

A

Kick-sampling and Simpson’s index

51
Q

Method used to sample freshwater invertebrates

A

Collect and identify invertebrates from a given area using a quadrat and a net
Kick/ rake the area for a set period and collect invertebrates in a net downstream
Release invertebrates carefully
Use Simpsons index to calculate diversity

52
Q

Technique used to sample plants

A

Quadrats and transects

53
Q

Method used to sample plants

A

Estimate percentage area cover of different plants using quadrat divided into 100
Measure plant diversity by counting number of plants in a quadrat

54
Q

Main hazards in field work

A
  • biting and stings - can scratch or cause allergic reaction - wear insect repellent and protective clothing
  • slippery surfaces - strains and sprains - footwear with grip
55
Q

How can genetic biodiversity be assessed

A

Determining the number or alleles at different loci within a given species
Taking samples of DNA from individuals in the population and determining DNA sequences by using gel electrophoresis to produce genetic fingerprints

56
Q

What are alleles

A

Different forms of genes

57
Q

What are loci

A

Position of genes on a chromosome

58
Q

What is polymorphism

A

Species has a number of different forms

59
Q

What is genetic polymorphism

A

Many different alleles for the same gene leading to different forms of the same organism

60
Q

How can genetic polymorphism be assessed

A

Determining the number of alleles at any one gene locus and the proportion of the population that has a particular allele

61
Q

How does biodiversity arise

A

By natural selection

62
Q

Steps in natural selection

A
  1. Mutations cause variations in individuals that can be inherited
  2. Offspring are overproduced which leads to intraspecific competition
  3. The variation that give a selective advantage means the individual is better fitted to survive selection pressure
  4. Individuals that have selective advantage survive and reproduce which passes the alleles to offspring
  5. Over many generations the allele frequencies of favourable variation increases
63
Q

What is a selection pressure and give examples

A

Something that causes the death of an organism

Eg predation, disease or climate

64
Q

Three types of adaptations

A

Anatomical, physiological, behavioural

65
Q

Anatomical adaptation

A

Physical features

66
Q

Physiological adaptations

A

Internal body process to regulate and maintain homeostasis

67
Q

Behavioural adaptations

A

In response to some external stimulus to survive

Wjec Biology Unit 2 (5 decks)

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