Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

AH Biology > Evolution > Flashcards

Evolution Flashcards

1
Q

What is evolution?

A

The change over time in the proportion of individuals in a population differing in one of more inherited traits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is an allele?

A

A different forms a gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

During evolution, changes in allele frequency occur due to…

A

Non-random processes of natural and sexual selection and random process of genetic drift

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Selection results in the non-random…

A

Increase in frequency of advantageous alleles
Decrease in frequency of deleterious alleles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What does natural selection act on?

A

Genetic variation within a population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does variation in traits arise as a result of?

A

Mutation- the original source of new DNA sequences

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are novel alleles?

A

New versions of genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

New DNA sequences can be…

A

Novel alleles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Most mutations are…

A

Harmful or neutral but in rare cases can be beneficial to the fitness of the individual

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Stages of natural selection

A
  1. Population produces more offspring than the environment can support
  2. Individuals with variations that are better suited to their environment tend to survive longer and produce more offspring
  3. Breeding passes on those alleles that confer an advantage to the next generation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is sexual selection?

A

Non-random process involving the selection of alleles that increase an individuals chances of mating and producing offspring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Sexual selection can be due to…

A

Male-male rivalry or female choice

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is male-male rivalry?

A

When size, strength or weaponry increases males’ access to females through conflict, large size and weaponry often go hand in hand
e.g. elephant seal (large size) and stag (weaponry)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Alleles that increase an individual’s chances of mating and producing offspring are…

A

Species specific

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Larger, stronger and greater weaponry leads to a…

A

Successful male as these are fitness characteristics that will be advantageous to offspring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Female choice involves…

A

Females assessing the fitness of males during rutting season and lekking

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is rutting season?

A

A recurrent period of sexual excitement and reproductive activity in certain male ruminants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is lek-mating?

A

A lek is an aggression of male animals gathered to engage in competitive displays to entice visiting females surveying prospective partners for fitness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Females assess… of the fitness of males

A

Honest signals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What do honest signals indicate?

A

Favourable alleles that increase the chances of offspring survival
Low parasite burden suggesting a healthy individual

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What do many species exhibit as a product of sexual selection?

A

Sexual dimorphism (distinct differences between sexes, typically size and colouration)

22
Q

Females are generally…
Males are usually more…

A

Inconspicuous
Conspicuous

23
Q

Reversed sexual dimorphism occurs in certain species such as…

A

Birds of prey e.g. peregrine falcon, males are smaller in size than females to be better adapted for hunting small prey for young during breeding season

24
Q

Genetic drift occurs when…

A

Chance events cause unpredictable fluctuations in allele frequencies from one generation to the next

25
What is a population bottleneck?
Event that drastically reduces population size
26
Bottleneck effect may be caused by...
Environmental disaster Overhunting (hunting species to the point of extinction) Habitat destruction that results in the death of organisms e.g. deforestation, coral bleaching Disease e.g. devil facial tumour disease, an aggression cancer
27
What is the founder effect?
Occurs when a few members of the population are isolated from the larger population so the gene pool of the new population is not representative of the original one
28
Genetic drift has a greater effect in... as...
Small populations, alleles are more likely to lost from the gene pool
29
How is a gene pool altered by genetic drift?
Under or over-representation of certain alleles and allele frequencies change
30
What are selection pressures?
Environmental factors that influence which individuals in a population can pass on their alleles
31
Selection pressures are either...
Biotic- competition, predation, disease, parasitism Abiotic- changes in temperature, light intensity, pH or salinity
32
What increases the rate of evolution?
Strong selection pressures
33
The Hardy-Weinberg principle states that...
in the absence of evolutionary influences allele and genotype frequencies in a population will remain constant over the generations, this stability is known as the Hardy-Weinberg equilibrium
34
Name evolutionary influences
Natural selection Sexual selection Genetic drift Mutation
35
What are the conditions for maintaining the Hardy-Weinberg equilibrium?
No natural selection No mutation No gene flow (through migration in or out of population) Random mating Large population size
36
The HW equilibrium can be used to...
Determine whether a change in allele frequency is occurring in a population over time, changes suggest evolution is occurring
37
Equation to calculate allele genotype ad phenotype frequencies in populations
p2 + 2pq + q2 =1 p2= frequency of homozygous dominant genotype 2pq= frequency of heterozygous genotype q2= frequency of homozygous recessive genotype
38
What is fitness?
An indication of a individual's ability to be successful at surviving and reproducing, refers to the contribution made to the gene pool of the next generation by individual genotypes
39
What is absolute fitness?
Ratio between frequency of individuals of a particular genotype after selection to those before
40
What is relative fitness?
Ratio of number of surviving offspring of a particular genotype to the number of surviving offspring per individual of the most successful genotype
41
Equation for absolute fitness
frequency of particular genotype after selection frequency of particular genotype before selection
42
Equation for relative fitness
no. of surviving offspring of particular genotype no. of offspring surviving per individual of most successful genotype
43
What is co-evolution?
The process by which two or more species evolve in response to selection pressures imposed by each other
44
What is the Red Queen hypothesis?
When a change in traits of one species acts as a selection pressure on the other species, species in these relationships must adapt to avoid extinction
45
What is symbiosis?
Co-evolved intimate relationship between members of two different species, impact for individuals can be positive, negative or neutral
46
3 types of symbiotic interactions
Mutualism Commensalism Parasitism
47
Co-evolution is often seen in pairs of species that have...
Symbiotic interactions
48
What is mutualism?
Both species involved in interaction are interdependent on each other for resources or other services, both species gain from relationship Often generates a structural compatibility between mutualistic partners +/+ interaction
49
What is commensalism?
Only one of the species (commensal) benefit (nutritional) and host is unaffected, usually involves commensal utilising dead parts/waste of host or taking advantage of disturbances caused by host 0/+ interaction
50
What is parasitism?
One species (parasite) benefits in terms of energy and nutrients while the other (host) is harmed as it loses energy and resources, incurs further costs for the host in defending it's tissues from parasitism attack +/- interaction

AH Biology (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions