Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Biology > Variation & evolution > Flashcards

Variation & evolution Flashcards

1
Q

What is variation?

A

-the differences in characteristics of individuals within a population

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

which two factors contribute to variation between organisms?

A

-the genes each individual inherits
-the environments each individual is exposed to

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

Who was Charles Darwin

A

-a 19th century biologist who developed and proposed the theory of evolution.

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

What is natural selection?

A

-the idea that in each generation, the individuals with the most favourable characteristics are most likely to survive and reproduce, therefore passing on their genes.

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

What is evolution?

A

-the process by which inherited characteristics of a population change over time due to natural selection
-this may result in the formation of a new species.

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

What does the phrase ‘survival of the fittest’ mean?

A

-the individuals with the most favourable characteristics are most likely to survive.

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

describe the process of natural selection

A

-In every population there is variation caused by mutation
-the mutation could lead to a beneficial characteristic
-the organism is better adapted to survive
-they’re going to reproduce
-the organism is going to pass the beneficial allele to offspring
-the allele frequency will rise.

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

why was Darwin’s theory controversial and only gradually accepted?

A

-a lot of people strongly believed God made all the animals and plants
-scientists felt that Darwin did not have enough evidence to back up his theory
-people did not understand how characteristics are inherited

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

What was Lamarck’s theory of evolution?

A

his theory suggested that organisms could acquire traits during their lifetime and pass these traits to their offspring

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

Why was Lamarck’s theory considered incorrect?

A

-acquired characteristics do not alter an organism’s DNA and thus cannot be inherited.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What key observation did Darwin make about species?

A

-that individual organisms within a species show a wide range of variation for specific traits.

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

What is the main difference between Lamarck’s and Darwin’s theories?

A

-Lamarck’s theory involved inheritance of acquired traits
-Darwin’s theory involved natural selection of existing variation.

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

What are four examples of selective breeding

A

-domestic dogs have been selectively bred to have a gentle nature
-food crops such as wheat has been selectively bred to be resistant to disease
-animals such as cows have been selectively bred to produce more meat or milk
-certain plants have been selectively bred to produce large or unusual flowers

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

describe the process of selective breeding

A
  • select the organisms with the desired characteristics
    -breed together
    -choose the offspring with desired characteristics
    -breed over many generations to create many organisms with desired characteristics
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is a disadvantage of selective breeding?

A
  • -if we breed together closely related animals or plants we can get inbreeding causing some breeds to be prone to disease or inherited defects
    -decreases the gene pool
    -the population as a whole will be more at risk
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is selective breeding?

A

-The process by which animals and plants are bred for desired characteristics.

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

Who was also working on the evolution theory other than Darwin?

A

-Alfred Russel Wallace

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

What is speciation?

A

-formation of a new species

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

What is the definition of species?

A

-a group of similar organisms that are able to interbreed to produce fertile offspring

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

How can scientists find out if two animals belong to the same species?

A

-by having them mate and produce fertile offspring

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

Describe the process of speciation

A

-geographical isolation separates the population
-There are different selection pressures in the two environments
-Mutations occur making the organisms better adapted to their own environment
-They are going to survive and reproduce
-They are going to pass the beneficial allele to the offspring.
-When we bring the two organisms together, they do not mate or produce fertile offspring.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what is genetic engineering?

A

-the process of cutting genes from the chromosomes of humans or other organisms and transferring them to cells of other organisms.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are genetically modified crops?

A

-GM crops are crops that have had their genes modified through genetic engineering to have specific characteristics.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are some examples of traits that GM crops might have?

A

-GM crops may be resistant to insect attacks or herbicides, and they generally show increased yields.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What are some concerns of GM crops?
-the effect on populations of wild flowers and insects -the uncertainty about the long-term effects of eating GM crops on human health
26
How is genetic modification being used in medical research?
-to explore the possibility of using genetic modification to overcome inherited disorders.
27
What is gene therapy?
-the treatment of an inherited disorder by giving the patient a healthy copy of the faulty gene.
28
How has genetic engineering played a role in the treatment of diabetes?
-bacterial cells have been genetically engineered to produce human insulin to treat diabetes
29
What are the steps of genetic engineering?
-identify the gene we want to transfer -use enzymes to isolate this gene -transfer the gene into a small circle of DNA called a plasmid or a virus both of which are vectors -the desired gene is transferred into the cells of the target organism e.g an animal, plant or bacterium at an early stage in the organism's development.
30
Why are genes transferred at an early stage?
-to make sure all of the cells receive the transferred gene so the organism develops with the characteristics we want.
31
What is tissue culture in plants?
-Using small groups of cells from part of a plant to grow identical new plants.
32
Why is tissue culture in plants important?
-for preserving rare plant species or commercially in nurseries.
33
What are cuttings in plant reproduction?
An older but simple method used by gardeners to produce many identical new plants from a parent plant.
34
What is the process of embryo transplants in animals?
Splitting apart cells from a developing animal embryo before they become specialised, then transplanting the identical embryos into host mothers.
35
What is adult cell cloning?
-A process where the nucleus is removed from an unfertilised egg cell, and the nucleus from an adult body cell (e.g., a skin cell) is inserted into the egg cell.
36
What are the steps involved in adult cell cloning?
-The nucleus is removed from an unfertilised egg cell. -The nucleus from an adult body cell (e.g., a skin cell) is inserted into the egg cell. -An electric shock stimulates the egg cell to divide and form an embryo. -The embryo cells contain the same genetic information as the adult skin cell. -When the embryo has developed into a ball of cells, it is inserted into the womb of an adult female to continue its development.
37
What happens when the embryo in adult cell cloning has developed?
-When the embryo has developed into a ball of cells, it is inserted into the womb of an adult female to continue its development.
38
What do the embryo cells in adult cell cloning contain?
-The embryo cells contain the same genetic information as the adult skin cell.
39
What is an advantage of cloning?
-the clones are genetically identical to the original plant so we know exactly what the clone's characteristics will be.
40
describe the method of cuttings (plants).
-a small piece of the plant is removed and dipped in rooting powder -rooting powder contains plant hormones which encourage the plant to develop roots
41
What are fossils?
-the remains of organisms from millions of years ago, which are found in rocks.
42
Why do many early forms of life leave few traces behind?
Many early forms of life were soft-bodied, which means they have left few traces behind. What traces there were have been mainly destroyed by geological activity.
43
Why can scientists not be certain about how life began on Earth?
Scientists cannot be certain about how life began on Earth because many early forms of life were soft-bodied (no shell or skeleton) , and their traces have been destroyed by geological activity.
44
What can we learn from fossils?
-how much or how little different organisms have changed as life developed on Earth.
45
Why is the fossil record incomplete?
-many organisms did not fossilize, and geological activity has destroyed many fossils.
46
Who was Gregor Mendel?
-a scientist and monk who, in the 19th century, carried out breeding experiments on plants
47
What organism did Mendel use for his genetic experiments?
-Pea plants -Mendel looked at their characteristics such as the shape of the pod or the colour of the flower
48
Why was the importance of Mendel's discovery not recognised until after his death?
-his findings were not published in a very well known journal. -scientists at the time didn't understand genetics and so couldn't properly appreciate/ contextualise his findings.
49
Who conducted breeding experiments in the mid-19th Century that led to foundational discoveries in genetics?
-Gregor Mendel.
50
What did Mendel propose about the inheritance of characteristics?
- each characteristic is determined by 'units' (now known as genes) that are passed on to descendants unchanged.
51
What significant observation about chromosomes was made in the late 19th Century?
-The behavior of chromosomes during cell division was observed.
52
What was discovered during the 20th century?
-'units', now called genes, were located on chromosomes. -the structure of DNA was determined and the mechanism of gene function worked out -this scientific work led to the gene theory being developed
53
When does extinction occur?
-when there are no remaining individuals of a species still alive
54
Why can bacteria evolve rapidly?
-they reproduce at a fast rate.
55
What do mutations of bacterial pathogens produce?
-new strains, some of which may be resistant to antibiotics.
56
What happens to bacteria that are resistant to antibiotics?
-Resistant bacteria survive and reproduce, leading to a rise in the population of the resistant strain.
57
Why do resistant strains of bacteria spread?
-people are not immune to them, and there is no effective treatment.
58
What is MRSA?
-MRSA is a type of bacteria that is resistant to antibiotics.
59
How can the development of antibiotic-resistant strains be reduced?
-Doctors should not prescribe antibiotics for non-serious or viral infections. -Patients should complete their full course of antibiotics to ensure all bacteria are killed. -The agricultural use of antibiotics should be restricted.
60
What are some cons of the development of new antibiotics ?
-costly and slow, and it is unlikely to keep up with the emergence of new resistant strains.
61
What are three ways fossils can be formed?
-when parts of organisms have not decayed which can happen when conditions needed for decay are absent -if parts of the organism are slowly replaced by minerals during the decay process -fossils can be the preserved traces of organisms
62
what are the reasons species can become extinct?
-due to a catastrophic event e.g asteroid -when the environment changes e.g changing weather patterns -a new disease or predator could kill all of the individuals of a species and make it extinct -if a new, more successful species evolves and competes with it
63
how do doctors treat bacterial diseases
-by using antibiotics such as penicillin
64
how is antibiotics used in farming?
-to prevent animals from developing bacterial diseases
65
describe how antibiotic resistance happens
-in every population there is genetic variation due to mutation -a mutation could make a bacterium resistant to antibiotics -an antibiotic would kill all other bacteria but the antibiotic resistant strain survives and reproduces without any competition from other bacteria -over time the population of the resistant strain rises -the resistant strain spreads as people are not immune to it and there is no effective treatment
66
What did Gregor Mendel discover from his experiments?
-that characteristics are not blended during inheritance e.g the shape of a pea pod has no effect at all on the colour of the flowers
67
what should the conditions for tissue culture be?
-sterile as we do not want to introduce any microorganisms such as bacteria or fungi
68
Who was Carl Linnaeus?
-an 18th century scientist who came up with the binomial system for naming organisms and the Linnaean classification system for classifying living organisms.
69
Describe the binomial naming system
-every species has a binomial name made up of two parts : the genus name & the species name -all letters should be lower case except the first letter of the genus name which should be upper case
70
What are three advantages of using a binomial system to name species
-each species has a new name which avoids confusion -allows scientists from different parts if the world to discuss species -can show how closely related organisms are ( close related organisms often have the same genus name )
71
What was the Linnaean classification system?
-Linnaeus classified living things into -kingdom -phylum -class -order -family -genus -species
72
Who was Carl Woese?
-a 20th century scientist who used microscopes and modern technology to develop the three-domain system to classify organisms
73
What are the three domains?
-Archaea -Bacteria -Eukaryota
74
What kingdoms does the domain eukaryota contain?
-Animals -Plants -Fungi -Protists
75
What is an evolutionary tree?
-a diagram that shows the evolutionary relationships between different organisms
76
How did Linnaeus classify the species into different categories?
-based on their structure and characteristics
77
What are Archae ?
-primitive bacteria often found in extreme conditions such as hot springs
78
What do scientists use to make an evolutionary tree?
-classification data on living organisms e.g their DNA -for extinct organisms scientists have to use fossils which can be a problem as fossil records of many species are incomplete

Biology (10 decks)

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