Organisms and Evolution Flashcards
1
Q
Sampling should be carried out in a manner that…
A
minimises impact on wild species and
habitats
2
Q
Consideration must be given to…
A
rare and vulnerable species and habitats that are protected
by legislation
3
Q
The chosen technique, point count, transect or remote detection must be
A
appropriate to
the species being sampled
4
Q
Quadrats
A
of suitable size and shape, or transects are used for plants and other sessile or
slow-moving organisms
5
Q
mobile species capture techniques…
A
Traps and nets
6
Q
Elusive species can be sampled directly using
A
camera traps or an indirect method, such as
scat sampling
7
Q
Identification of an organism in a sample can be made using…
A
classification guides,
biological keys, or analysis of DNA or protein
8
Q
Organisms can be classified by…
A
both taxonomy and phylogenetics
9
Q
Taxonomy
A
involves the identification and naming of organisms and their classification into groups based on shared characteristics
10
Q
Phylogenetics
A
is the study of the evolutionary history and relationships among individuals
or groups of organisms
11
Q
Phylogenetics is changing…
A
the traditional classification of many organisms
12
Q
Familiarity with taxonomic groupings allows…
A
predictions and inferences to be made about
the biology of an organism from better-known (model) organisms
13
Q
Model organisms are those that..
A
are either easily studied or have been well studied
14
Q
indicator species
A
Presence, absence or abundance of indicator species can give information of
environmental qualities, such as presence of a pollutant
15
Q
Susceptible and favoured species can be used to…
A
monitor an ecosystem
16
Q
Methods of marking animals
A
banding, tagging, surgical implantation, painting and
hair clipping
17
Q
The method of marking and subsequent observation must minimise the…
A
impact on the
study species
18
Q
Some of the measurements used to quantify animal behaviour are…
A
latency, frequency and
duration
19
Q
ethogram
A
behaviours shown by a species in a wild context allows the
construction of time budgets
20
Q
anthropomorphism
A
needs to be avoided as this can lead to invalid conclusions
21
Q
Evolution
A
is the change over time in the proportion of individuals in a population differing in
one or more inherited traits
22
Q
During evolution
A
changes in allele frequency occur through the non-random processes of
natural selection and sexual selection, and the random process of genetic drift
23
Q
Natural selection acts on…?
A
acts on genetic variation in populations
24
Q
Populations produce
A
more offspring than the environment can support
25
Individuals with variations that are better suited to their environment tend
to survive longer
and produce more offspring, breeding to pass on those alleles that conferred an advantage
to the next generation
26
Sexual selection
is the non-random process involving the selection of alleles that increase the individual’s chances of mating and producing offspring
27
Sexual selection may lead to
sexual dimorphism
28
Sexual selection can be due to
male-male rivalry and female choice
29
Genetic drift occurs when
chance events cause unpredictable fluctuations in allele
frequencies from one generation to the next
30
Genetic drift is more important in...
small populations, as alleles are more likely to be lost
from the gene pool
31
Bottleneck effect
The bottleneck effect in biology refers to a sharp reduction in the size of a population due to environmental events, such as natural disasters (floods, fires, earthquakes) or human activity (habitat destruction, overhunting). This reduction in population size drastically limits genetic diversity, as only a small, random subset of individuals survives to repopulate the species.
32
Founder effect
type of genetic drift that occurs when a small group of individuals from a larger population establishes a new population in a new area. Because the founding members are a small sample of the original population, they carry only a limited subset of the genetic diversity from the original population. This reduced genetic diversity can lead to a population that is genetically different from the original one, even if the new population grows in size over time.
33
A gene pool is altered by genetic drift because...
certain alleles may be under-represented or
over-represented and allele frequencies change
34
Where selection pressures are strong, the...
rate of evolution can be rapid
35
The Hardy-Weinberg (HW) principle states that...
in the absence of evolutionary influences,
allele and genotype frequencies in a population will remain constant over the generations. The HW principle can be used to determine whether a change in allele frequency is
occurring in a population over time
36
Fitness
an indication of an individual’s ability to be successful at surviving and reproducing. It refers to the contribution made to the gene pool of the next generation by individual
genotypes
37
Absolute fitness
the ratio between the frequency of individuals of a particular genotype before and after selection
38
Relative fitness
the ratio of the number of surviving offspring per individual of a particular genotype to the number of surviving offspring per individual of the most successful genotype
39
Co-evolution
the process by which two or more species evolve in response to selection
pressures imposed by each other
40
types of symbiotic interactions
Mutualism, commensalism, and parasitism
41
42
What is a cost of sexual reproduction?
Males unable to produce offspring
## Footnote
Only half of each parent’s genome is passed onto offspring, disrupting successful parental genomes.
43
What is the primary benefit of sexual reproduction?
Increased genetic variation in the population
44
How does genetic variation contribute to the survival of sexually reproducing organisms?
Provides the raw material required for adaptation
45
What hypothesis explains the persistence of sexual reproduction?
The Red Queen hypothesis
46
What type of interactions may select for sexually reproducing hosts?
Co-evolutionary interactions between parasites and hosts
47
How does sexual reproduction affect susceptibility to parasites?
Reduces the chances that all offspring will be susceptible
48
What is a key advantage of asexual reproduction?
Whole genomes are passed on from parent to offspring
49
In what situations is maintaining the parent's genome advantageous?
In very narrow, stable niches or when re-colonising disturbed habitats
50
What are examples of asexual reproduction in eukaryotes?
Vegetative cloning in plants and parthenogenesis in lower plants and animals
51
What is a benefit of asexual reproduction regarding offspring production?
Offspring can be reproduced more often and in larger numbers
52
Where is parthenogenesis more common?
In cooler climates or regions of low parasite density or diversity
53
What is a limitation of asexually reproducing populations?
Not able to adapt easily to changes in their environment
54
What allows some degree of variation in asexually reproducing populations?
Mutations can occur
55
What mechanisms do organisms that reproduce asexually often have?
Mechanisms for horizontal gene transfer
56
What are examples of organisms that utilize horizontal gene transfer?
Bacteria and yeasts
57
What is meiosis?
The division of the nucleus that results in the formation of haploid gametes from a diploid gametocyte
## Footnote
Meiosis is essential for sexual reproduction.
58
In diploid cells, how do chromosomes typically appear?
As homologous pairs
## Footnote
Homologous pairs consist of one chromosome from each parent.
59
What occurs during meiosis I?
The chromosomes condense, homologous chromosomes pair up, and chiasmata form.
## Footnote
Chiasmata are points of contact where genetic material can be exchanged.
60
What are chromatids?
Genetically identical copies of a chromosome attached at the centromere
## Footnote
Each replicated chromosome consists of two sister chromatids.
61
What is crossing over during chiasmata?
The exchange of sections of DNA between non-sister chromatids of a homologous pair
## Footnote
This process increases genetic diversity.
62
What is the significance of the random orientation of homologous chromosomes at the equator?
It contributes to genetic variation in gametes
## Footnote
This randomness is a key feature of meiosis.
63
What happens to homologous chromosomes during meiosis I?
They are separated and move towards opposite poles
## Footnote
This separation reduces the chromosome number by half.
64
What occurs after meiosis I?
Cytokinesis occurs and two daughter cells form.
## Footnote
Each daughter cell is haploid.
65
What happens during meiosis II?
The sister chromatids of each chromosome are separated
## Footnote
Meiosis II resembles mitosis but starts with haploid cells.
66
What determines the sex of birds, mammals, and some insects?
The presence of sex chromosomes
## Footnote
In mammals, the SRY gene on the Y chromosome is crucial for male development.
67
Which gene on the Y chromosome is responsible for male characteristics in most mammals?
SRY gene
68
What type of males lack most corresponding homologous alleles on the Y chromosome?
Heterogametic (XY) males
69
What can result in sex-linked patterns of inheritance?
The lack of homologous alleles in heterogametic males
## Footnote
Examples include carrier females (XBXb) and affected males (XbY).
70
What happens to one of the X chromosomes in homogametic females (XX)?
It is randomly inactivated at an early stage of development
71
Why is X chromosome inactivation important?
It prevents a double dose of gene products, which could be harmful to cells
72
Why are carriers less likely to be affected by deleterious mutations on X chromosomes?
Because of X chromosome inactivation
73
What is the result of random X chromosome inactivation in tissues?
Half of the cells will have a working copy of the gene in question
74
What are hermaphrodites?
Species that have functioning male and female reproductive organs in each individual
75
What do hermaphrodites produce?
Both male and female gametes
76
What is the benefit of being a hermaphrodite?
No requirement for a partner of the opposite sex if encountering a partner is rare
77
In some species, what factors determine sex and sex ratio?
Environmental factors rather than genetic factors
78
Can sex change within individuals of some species?
Yes, due to size, competition, or parasitic infection
79
How can the sex ratio of offspring be adjusted in some species?
In response to resource availability
80
81
What is the primary difference in investment between males and females in reproduction?
Greater investment by females
## Footnote
Females typically invest more energy and resources in producing eggs compared to males producing sperm.
82
How does parental investment affect the probability of young survival?
Parental investment is costly but increases the probability of production and survival of young
## Footnote
Investing resources in offspring can lead to higher chances of their survival and reproductive success.
83
What are r-selected organisms characterized by?
r-selected organisms are characterized by a high number of offspring and low parental investment
## Footnote
These organisms often thrive in unstable environments.
84
What are K-selected organisms characterized by?
K-selected organisms are characterized by fewer offspring and high parental investment
## Footnote
These organisms tend to thrive in stable environments.
85
In what type of environments does r-selection typically occur?
r-selection tends to occur in unstable environments
## Footnote
In these environments, species have not reached their reproductive capacity.
86
In what type of environments does K-selection typically occur?
K-selection tends to occur in stable environments
## Footnote
These environments allow for more investment in fewer offspring.
87
External fertilisation Benefits
Very large numbers of offspring produced.
88
External fertilisation costs
Many gametes are predated or not fertilised.
no/limited parental care
few offspring survive
89
Internal fertilisation costs
mate needed which requires energy expenditure
requires direct transfer of gametes from one partner to another
90
internal fertilisation benefits
increased chance of successful fertilisation
fewer eggs needed
offspring retained internally for protection
higher offspring surv rate
91
What are mating systems based off of?
how many mates an individual has during one breeding season
92
polygamy
individuals of one sex having more than one mate.
93
94
What are the two types of polygamy?
polygyny and polyandry
95
polygyny
one male mates exclusively with a group of females
96
polyandry
one female mates with a number of males in the same breeding season
97
monogamy
involves the mating of a pair of animals to the exclusion of anothers
98
What are courtship rituals?
a set of display behaviours which animals use to attract a mate. These are common in birds and fish
99
successful courtship in birds and fish can be a result of...?
species-specific sign stimuli and fixed action responses
100
What does sexual selection select?
characteristics that have little survival benefit for the individual , but increase their chance of mating.
101
Result of sexual selection
sexual dimorphism
102
sexual dimorphism
females are generally inconspicuous, with bland colours and lacking ornate structures.
103
Reversed sexual dimorphism
females are conspicuous and males are inconspicuous.
104
what does female choice involve?
females assessing honest signals of the fitness of males.
105
What are honest signals?
indicates favourable alleles that increase the chances of survival of offspring or a low parasite burden.
106
What is lekking?
some birds species display lekking behaviour. Involves males of the species gathering to display at a lek, where female choice occurs.
107
What area of a lek do satelite males occupy
fringes
108
how is access to females for mating increased.
success in male rivalry through conflict
109
Niche
a multi-dimensional summary of tolerances and requirements of a species
110
Fundamental niche
that it occupies in the absence of any interspecific competition.
111
realised niche
the range that they have been fittest in comparison to other organisms present.
112
What is competitive exclusion?
As a result of interspecific competition. Occurs where the niches of two species are so similar that one declines to local extinction.
113
When species realised niches are sufficiently different...
potential competitors can co-exist by resource partitioning.
114
Parasitism
A symbiotic interaction between a parasite and its host (+/-). A parasite gains benefit in terms of nutrients at the expense of its host.
115
Reproductive potential of a parasite
unlike in a predator-prey relationship, the reproductive potential of the parasite is greater than that of the host.
116
Most parasites have a narrow realised niche because...
they are host specific
117
As the host provides so many of the parasite’s needs, many parasites are degenerate...
they lack in structures and organs found in other organisms.
118
Ectoparasites vs endoparasites
ectoparasites live on the surface of their host, whereas an endoparasite lives within the tissues of its host.
119
What is a Vector?
plays an active role in the transmission of the parasite and may also be a host.
120
Malaria is caused by
Plasmodium.
121
Schistosomiasis is caused by
schistosomes
122
What are viruses
parasites which can only reproduce in host cells. some virsuses are surrounded by a phospholipid membrane derived from host cell materials.
123
What do viruses contain?
genetic material in the form of DNA or RNA, packaged in a protein coat.
124
What does the outer surface of viruses contain?
antigens that a host cell may or may not be able to detect as foreign.
125
Viral life cycle stages
infection of host cell with genetic material, host cell enzymes
replicate viral genome, transcription of viral genes and translation of viral proteins,
assembly and release of new viral particles
126
RNA retroviruses use which enzyme?
reverse transcriptase to form DNA, which is then inserted into the genome of the host cell
127
Viral genes can then be expressed to form...
new viral particles
128
What is transmission
the spread of a parasite to the host
129
what is Virulence
the harm caused to a host species by a parasite
130
How are ectoparasites transmitted
direct contact
131
How are endoparasites transmitted
Endoparasites of the body tissues are often transmitted by vectors or by consumption of intermediate hosts
132
Factors increasing transmission rates
-the overcrowding of hosts when they are at high density
- mechanisms, such as vectors and waterborne dispersal stages, that allow the parasite
to spread even if infected hosts are incapacitated
133
How do parasites maximise transmission rates?
Host behaviour is often exploited and modified by parasites to maximise transmission
134
The host behaviour becomes part of ...
the extended phenotype of the parasite
135
How do parasites benefit the parasite growth, reproduction or transmission?
Parasites often suppress the host immune system and modify host size and reproductive rate in ways that benefit the parasite growth, reproduction or transmission
136
examples of Non-specific defences
Physical barriers, chemical secretions, inflammatory response, phagocytes, and natural killer cells destroying cells infected with viruses are examples of non-specific defences
137
specific cellular defences
A range of white blood cells constantly circulates, monitoring the tissues
138
If tissues become damaged or invaded...
cells release cytokines that increase blood flow resulting in non-specific and specific white blood cells accumulating at the site of infection
or tissue damage
139
Mammals contain many different...
lymphocytes, each possessing a receptor on its surface,
which can potentially recognise a parasite antigen. Binding of an antigen to a lymphocyte’s receptor selects that lymphocyte to then divide and
produce a clonal population of this lymphocyte
140
Some selected lymphocytes will produce...
antibodies, others can induce apoptosis in
parasite-infected cells
141
Antibodies possess regions where...
the amino acid sequence varies greatly between different antibodies. This variable region gives the antibody its specificity for binding antigen
142
When the antigen binds to this binding site...
the antigen-antibody complex formed can result
in inactivation of the parasite, rendering it susceptible to a phagocyte, or can stimulate a response that results in cell lysis. Memory lymphocyte cells are also formed
143
Endoparasites mimic..
host antigens to evade detection and modify host immune response
to reduce their chances of destruction
144
Antigenic variation in some parasites allows them to change between...
different antigens
during the course of infection of a host. It may also allow re-infection of the same host with the new variant
145
Some viruses escape immune surveillance by?
integrating their genome into host genomes,
existing in an inactive state known as latency. The virus becomes active again when favourable conditions arise
146
Epidemiology
is the study of the outbreak and spread of infectious disease
147
herd immunity threshold
the density of resistant hosts in the population required to
prevent an epidemic
148
Why is it difficult to find a drug that only targets the parasite?
The similarities between host and parasite metabolism makes it difficult to find drug
compounds that only target the parasite
149
What has to be reflected in the design of vaccines?
Antigenic variation
150
Why is it difficult to make some vaccines?
The parasites are difficult to culture
151
Challenges arise where parasites spread most rapidly as a result...
overcrowding or tropical climates. These conditions make co-ordinated treatment and control programs difficult to achieve
152
Civil engineering projects to improve sanitation combined with co-ordinated vector control
may often be...
the only practical control strategies
153
improvements in parasite control reduce..
child mortality and result in population-wide improvements in child development and intelligence, as individuals have more resources
for growth and development
154
What enviroment is parthenogenesis most likely to occur in?
cool climates with low parasite density
