unit 2 Flashcards
(141 cards)
1
Q
what is the definition of evolution
A
the change overtime in proportion of individuals in a population differing in one or more inherited traits
2
Q
What does natural selection act on
A
Genetic variation as a result of mutation
3
Q
What is the original sequence of DNA
A
Mutation
4
Q
What are selection pressures due to
A
when populations produce more offspring than the environment can support.
5
Q
how are advantageous alleles passed on to offspring
A
through beneficial variations of genetic material, allowing them to survive for longer allowing for more offspring to be produced.
6
Q
what does selection result in
A
non-random increase in frequency of advantageous alleles and non-random decrease in the frequency of deleterious alleles.
7
Q
what is sexual selection
A
non-random process involving selection of alleles that increase the individua;s chances of mating
8
Q
What can sexual selection lead to
A
Sexual dimorphism
(male-male rivalry, Female Choice)
9
Q
what is sexuaal dimorphism
A
where two sexes of the same species exhibit different characteristics, birds
(mating ritual)
10
Q
male-male rivalry
A
large size or weaponry increases access to females through conflict
11
Q
female choice
A
females assess male fitness, result in men preforming to attract them
12
Q
when does Genetic Drift occur
A
chance events cause unpredictable fluctuations in allele frequencies from one generatiion to the next.
13
Q
where is genetic drift important
A
In small populations, as alleles are more likely to be lost from the gene pool.
14
Q
what is the bottleneck effect
A
a population size is reduced for at least one generation. The reduce population can have lower genetic diversity
15
Q
What is the founder effect
A
the isolation of a few members of a population from a larger population. The gene pool of the new population is not representative of that in the original gene pool
16
Q
what is a gene pool altered by + why
A
genetic drift bc certain alleles may be under represented or over-represented and allele frequencies change
17
Q
what does it mean if selection pressures are strong
A
rate of evolution can be rapid
18
Q
biotic examples
A
competition, predation, disease parasitism
19
Q
describe Abiotic
A
changes in temperature, light, humidity,pH salinity
20
Q
What is the Hardy-Weinberg Principle
A
in the absence of evolutionary influences, allele and genotype frequencies in a population will remain constant over the generations
21
Q
what are conditions for the HW equilibrium
A
no selection
no mutation
no migration
large population
random mating
22
Q
what is the HW principle used for
A
to determine whether a change in allele frequency is occurring in a population over time. Changes suggest evolution is occuring.
23
Q
What does the equations stand for
p^2 + 2pq +q^2 = 2
A
P= of dominant allele
q= recessive allele
P^2= homozygous dominant genotype
2pq=frequency of heterozygous genotype
q^2=homozygous recessive genotype
24
Q
what is coevolution
A
when two or more species evolve in response to selection pressure imposed by each other
25
what is it called when co-evolution is frequently seen in pairs
symbiotic relationships
26
what is symbiotic/ symbiosis
co-evolved intimate relationships between members of two different species
27
what are different types of symbiosis
mutualism, commensalism and parasitism
28
describe mutualism
when both organisms are interdependent on each other for resources or other sources
29
describe commensalism
only benifets one of the organisms
30
parasitism
benefits in terms of energy or nutrients and host is harmed as the result of the loss
31
what is the red queen hypothesis
ina coevolutionary relationship, change in the traits of one species can act as a selection pressure on the other species. this means that species in theses relationships must adapt to avoid exctinction
32
what is sexual reproduction
production of new living organisms by combining genetic information from two individuals of different types
33
what are costs of sexual reproduction
males being unable to produce offspring,
only half of parents genome passed on, not all advantageous alleles are passed on
34
what does genetic variation provide in sexual reproduction
raw material required for adaptation, giving sexually reproducing organisms a better chance of survival under changing selection processes.
35
how does red queen hypothesis explain the persistence of sexual reproduct
Parasite pressure maintains sexual reproduction in the host population by selecting for the ability to produce rare genotypes are resistant to infection
36
when will hosts have a greater fitness
when they are able to resist and tolerate parasitism
37
when will parasites have a greater fitness
when they feed reproduce and find new hosts
38
what happens if hosts reporoduce sexually
the genetic variability in their offspring reduces the chances that they will be susceptible to infection by parasites
39
what is asexual reproduction
type of reproduction by which offspring arise from a single organism and inherit the genes of that parent only. it does not involve fusion of gametes
40
why is asexual reproduction successful
whole genomes are passed from parent to offspring
41
when is maintaining the genome an advantage
in narrow, stable nices or when recolonising disturbed habitats
42
what are examples of Asexual reproduction in eukaryotes
vegetative cloning and parthenogenesis that lack fertilisation
43
what is parthenogenesis
reproduction from female gamete without fertilisation.
44
where is parthenogenesis more common
in cooler climates,
bc they are disadvantageous to parasites or regions of low parasite density or diversity
45
what are Asexual reproducing populations unable to do
adapt easily to changes in their environment
46
what is horizontal gene transfer
prokaryotes can exchange genetic material horizontally resulting in faster evolutionary change than in organisms that only use vertica; transfer
47
what is meiosis
division of the nucleus that results in the formation of haploid gametes form a diploid gametocyte
48
hwat are homologous chromosomes
chromosomes of the same size, same centromere position and with the same sequence of genes at the same location
49
what is the stages of meiosis split into
meiosis I
meiosis II
50
what do the chromosomes replicated prior to meiosis I consist
two genetically identical chromatids attached at the centromere
51
how is sex determined
by the presence of sex chromosoems
52
What is a sex chromosome
a chromosome that participates in sex determination
53
what is the sex chromosomes in men and women
M=XY
W=XX
54
what is an sry gene
its on the Y-chromosome and determines the development of male characteristics.
55
what problems can arise when heterogametic males lack most of the corresponding homologous alleles on the shorter Y chromosome
sex linked patterns of inheritance as seen with carrier demales
56
what happens to one of the chromosomes in a homogametic female
one of the chromosomes present in each cell is randomly inactivated at an early stage of development
57
what does x chromosome inactivation do
prevents a double dose of gene products that could be harmful
58
what mutations are X carriers less likely to be affected by
deleterious mutations.
59
what is a hermaphrodite
a species that have high functioning male and female reporductive organs in each individual. They produce both male and female gametes and usually gave a partener with which to excange gametes
60
what is the benefit to individual organism being a hermaphrodite
there is more chance of finding a mate as there is no sex requirement
61
what is environmental sex determination
when the sex is dependant on the environmento
62
what can sex change within individuals due to
size, competition, parasitic infection
63
how can the sex ration of offspring be adjusted
in response to resource availability
64
what sex usually invests the most parental investment
the female
65
describe parental investment
It is costly but increases the probability of production and survival of young
66
what are the two parental behaviours
R-selected
k-selected
67
Describe R-selected species
small with short lifespan
short generation time
quick maturation time
Often only once
large amount of small offspring
limited parental care
small energy input by parents
low offspring survival probability
68
Describe k-Selection species
Large with long lifespan
Long generation time
Slow Maturation time
multiple times of amount of reproduction
small amount of large offspring
high level of parental care
large energy input by parents
high offspring survival probability
69
where do r-selection tend to occur
in unstable environments where the species has not reached its reproductive capacity
70
where do k-selection tend to occur
in stable environments
71
what is internal fertilisation
the process by which the sperm and egg neuclei fuse inside the female
72
what is external fertilisation
the process by which the sperm and egg nuclei fuse outside the female
73
what are benefits of internal fertilisation
benefits
increased chance of successful fertilisation
fewer eggs needed
offspring can be retained internally for protection and/or development
higher offsrping susvival rate
74
what are cons of internal fertilisation
a mate must be located which requires energy expenditure
requires direct transfer of gametes from one partner to another
75
what are benefits from external fertilisation
very large numbers of offsprings can be produced
76
what are cons of external fertilisation
NO or limited parental care
many gametes predated or not fertilised
few offspring survive
77
what is monogamy
the mating of a pair of animals to the exclusion of all others
78
what is polygamy
individuals of one sex have more than one mate
79
what do polygyny
one male have a group of females that breed exclusively
80
what is polyandry
one femal mates with a number of males in the same breeding season
81
what is a courtship ritual
A set of display behaviours in which an animal usually a male attempts to attract a male
82
what does successful courtship behaviour in birds and fish result in
species specific sign stimuli
fixed action pattern responces
83
what is sexual selection
selecting mates due to their looks, not for suvival benefit but in chances for mating
84
what is sexual dimorphism
physical difference between males and females of a species.
85
what sexual dimorphism do vultures have
reversed sexual dimorphism
86
what is female choice
females assessing honest signals of the fitness of males
87
what is an honest signal
signals and behaviours in animals that are a true representation of their biological fitness
88
what do honest signals indicate
favourable alleles that increase the chance of survival of offspring or low parasite burden suggesting a healthy individual.
89
what is Lekking
during a lek males will display for females in a communal display area then females will choose a mate
90
what increases access to females for mating
male on male rivalry through conflict
91
what is a niche
functional role that it plays within an ecosystem
92
what is an ecological niche
is a multi-dimensional summary of tolerances and requirements of a species
93
what does it mean if a species has a fundamental niche
there is an absence of any interspecific competition
94
what is a realised niche
is occupied in response to interspecific competition
95
what is a result of interspecific competition
competitive exclusion can occur, where the niches of two species are so similar that one declines to local extinction.
96
where can potential competitors co-exist with resource partitioning
where realised niches are sufficiently different
97
what interaction is parasitism
symbiotic
98
unlike predator-prey relationship what is the reproductive potential for parasites
parasites will have a greater reproductive potential than that of the host
99
what niche do parasites have and why
narrow/specialised niche
they are host-specific
100
why are parasites described as degenerate
and what does this mean
the host provides many of the parasites needs
it doesn't have organs or other structures
101
what does it mean if the parasite is ectoparasitic
it lives on the surface of the hostw
102
what does it mean if the parasite is endoparasitic
lives within the tissue of its host
103
what is a definitive host
the organism on or in which a parasite reaches sexual maturity
104
Intermediate host meaning
the host that the parasite might require in order to complete its life cycle
105
what is a vector
it plays an active role in the transmission of the parasite and may also be a host
106
what is a virus
parasites that can only replicate inside a host cell.
107
how do viruses contain genetic info
through DNA or RNA, packaged in a protective protein coat
108
wat can some viruses be surrounded by
phospholipid membrane derived form host cell materials
109
what does the outer surface of a virus contain
antigens,, that a host cell may or may not be able to detect as foreign
110
what does RNA retroviruses use to form DNA that is then inserted into the genome of the host cell
reverse Transcriptase
111
what does using reverse transcriptase
viral genes can then be expressed to form new viral particles
112
Transmission meaning
the spread of parasite to a host new viral particles
113
virulence meaning
the harm caused to a host species by a parasite
114
how are ectoparasites transmitted
through direct contact or by consumption
115
how are endoparasites transmitted
through vectors
116
what factors increase transmission
overcrowding of hosts when they are at high density
mechanisms such as vectors and waterborne dispersal stages allow parasite to spread
117
how is host behavior affected by parasites and why
exploited and modified
this maximises transmission
118
what can be affected by parasites in the host
foraging, movement, sexual behaviour, habitat choice or antipredator behaviour
119
what happens to the host behaviour once it is exploited
becomes part of the extended phenotype
120
what does the parasite do to benefit growth, production and transmission
suppress immune system
modify host size
modify reproductive rate
121
what does the immune response in mammals contain
non-specific and specific aspects
122
what is a nonspecific defence
attempt to prevent any parasite from infecting the potential host
123
what are examples of non-specific response
physical barriers (skin)
chemical secretions
inflammatory response
phagocytes
natural killer cells
124
what is the definition of specific cellular defences
used to prevent any parasite from entering the body with a particular method.
125
examples of specific cellular defences
antigens/ antibodies
126
what increases blood flow
cytokines
127
what does cytokines production result in
non-specific and specific WBC accumulating at the site of infection or tissue damage
128
how is a clonal population produced
by binding of antigen to a lymphocyte receptor selects that lymphocyte to divide
129
what will the selected lymphocytes do in immune evasion
Some produce antibodies
some induce apoptosis
130
what are the regions that antibodies posess
and what does that mean
amino acid sequences varies between different antibodies
allows for antibody specificity
131
what is formed when the antigen binds to the binding site, and what does it result in
Antigen-antibody complex.
inactivation of the parasite, rendering susceptible to a phagocyte
132
what happens during initial antigen exposure
memory lymphocyte cells can be produced which are specific for an antigen
133
what do endoparasites do
mimic host antigens to evade detection and modify host immune response to reduce chances of destruction
134
what allows parasites to change antigens during course of infection
antigenic variation
135
how do some viruses escape immune survaillance. what is this known as
by integrating their genome into host genomes, Latency
136
what is epidemiology
the study of the outbreak and spread of infectious disease
137
herd immunity
the resistance to the spread of contagious disease that results if a sufficiently high proportion of individuals are immune to the disease
138
what makes it difficult to find drug compounds that only target the parasite
similarities between host and parasite in metabolism.
parasites are difficult to culture in a lab increases difficultuy for vaccines
139
where are outbreaks of parasites most likely to occur
overcrowded areas (refugee camps, rapidly growing cities )
140
what can help reduce parasites
civil engineering projects to improve sanitisation and coordinated vector control may often be the only practical control strats
141
