Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

A Level Biology Edexcel A > Biodiversity & Natural Resources Year 2 > Flashcards

Biodiversity & Natural Resources Year 2 Flashcards

1
Q

Define Biodiversity.

A

The variety of species and the range of taxa (species diversity) the variety of alleles within a species (genetic
diversity) and the
variety of ecosystems (ecosystem diversity) of which organisms are a part.

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

Define biodiversity hotspot.

A

An area with very high biodiversity.

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

Define species.

A

A group of organisms with homologous features (similar anatomy, physiology and behaviour), which can interbreed to produce fertile offspring and are reproductively isolated from other species in time, place or behaviour (geographical isolation results in reproductive isolation).

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

Define species richness.

A

The variety of different species present in a habitat at any one time.

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

Define species evenness.

A

The number of organisms (population size) of each species in a habitat.

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

What is the equation for calculating biodiversity index?

A

D = N(N-1)/ sum of n(n-1)

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

Define endemic species.

A

A species which is only found in one geographical location.

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

Define niche.

A

The role of an organism/ species within its habitat/ ecosystem.

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

Define competition.

A

The struggle between two organisms for the same limited resource within the environment.

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

List the possible niches of an organism.

A

• be a producer
• be a decomposer
• be a food source for another organism
• provide shelter for other organisms
• be a pollinator

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

What is adaptation?

A

Adaptation is when organisms have specialised features that increase their chance of survival and reproduction in the environment in which they live. This means they can then pass alleles /genes for these advantageous characteristics on to their offspring in the next generation.

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

What are the 3 types of adaptations?

A

• Behavioural
•Phsyiological
• Anatomical

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

Define behavioural adaptation.

A

How an organism behaves to increase its chance of survival. e.g birds mating dance

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

Define physiological adaptation.

A

Processes inside an organism that increase its chance of survival or reproduction. e.g venom produced by snake

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

Define anatomical adaptation?

A

Structural features of an organism that increase its chance of survival or
reproduction.

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

Define co-adaptation.

A

When two different species evolve together in tandem and become dependent on each other, making them more closely adapated.

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

Define evolution.

A

A change in allele frequency in a population over time.

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

Define allele frequency

A

The relative frequency with which an allele is found in a population.

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

Define selection pressure.

A

A change in the environment that can affect the organsims’s ability to survive in a given environment e.g. new predator, use of antibiotics.

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

What is meant by struggle for existence?

A

Competition between members of a species for resources for survival and reproduction.

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

Describe the process of natural selection.

A

• There is genetic variation in the population due to a random mutation which can be an advantageous allele which aids survival in the environment which has a specific selection pressure (e.g. allele for disease resistance)
• This increases the chance of survival and reproduction passing on the advantageous allele to the offspring.
• Therefore evolution has occurred as the allele frequency for the advantageous allies has increased over time.

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

The ability of a population to adapt quickly will depend on:

A

• strength of selection pressure
• the reproductive rate of the organism
• the size of the gene pool

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

How do you calculate allele frequencies?

A

p + q = 1

where p = frequency of dominant allele
q = frequency of recessive allele

24
Q

State the Hardy-Weinberg equation.

A

p² + 2pq + q² = 1

Frequency of homozygous dominant individuals + frequency of heterozygous individuals + frequency of homozygous recessive individuals = 1

25
Q

What is the Hardy-Weinberg equation used for?

A

Used to see whether there has been a change in allele frequencies over time. (if evolution has occurred). This can be done by comparing allele frequencies at two points in time, if the frequency has changed this indicates evolution has occurred.

26
Q

What does the Hardy-weinberg principle state in terms of the conditions for evolution not to occur.

A
  • The population size is large enough for genetic drift not to occur.
  • Mating is random
  • There is no gene flow
  • No mutations/ are rare
  • No natural selection

If any of these conditions are not met, a change in allele frequencies can occur.

27
Q

Define gene pool.

A

All the alleles of all the genes present in a population of a species.

28
Q

Define genetic diversity.

A

The number of different alleles in a population/ gene pool, and the frequency of different alleles in a particular species.

29
Q

How can genetic diversity be measured?

A
  • Can be observed in the external phenotype
  • DNA sequencing
  • Gel electrophoresis
  • Heterozygosity index can be calculated.
30
Q

Give the equation used to calculate the heterozygosity index.

A

H = number of heterozygotes/ number of individuals in the population.

31
Q

Why is genetic diversity important?

A

It increases the gene pool which increases the chance of a mutation which may be an advantageous allele so gives the organsim a selective advantage and aids the survival and reproduction in the environment with a specific selection pressure.

32
Q

Give the two types of speciation.

A
  1. Allopatric
  2. Sympatric
33
Q

What is allopatric speciation?

A

Speciation that occurs as a result of geographical isolation between populations.

34
Q

What is sympatric speciation?

A
35
Q

Give some methods of isolation.

A
36
Q

Describe the system for naming species.

A

Carl Linnaeus came up with the binomial system of nonmenclature, which gives every species a unique two part Latin name. First part of the name indicates the genus (upper-case letter) and second part indicates species (lowe-case letter).

37
Q

What is taxonomy?

A

Taxonomy is the science of classifying living organisms.

38
Q

Define taxonomic heirarchy.

A

A taxonomic heirarchy is a series of taxa where organisms share one or more common features and a common ancestor. Organisms are first divided into large groups, then subdivided into increasingly smaller groups.

39
Q

Give the taxonomic heirarchy.

A
  1. Kingdom
  2. Phylum
  3. Class
  4. Order
  5. Family
  6. Genus
  7. Species
40
Q

How do taxonomists classify living organisms?

A

Organisms are placed into groups (taxonomic groups) based on similarities in phenotype and genotype. Molecular phylogeny is used to identify similarities in DNA base sequences. Organisms that have features in common will be placed in the same taxonomic group.

41
Q

Classification is built around the species concept - what is this?

A

Organisms which have similar characteristics and DNA and can interbreed to produce fertile offspring are placed in the same species.

42
Q

State the 5 kingdoms.

A
  • Animalia
  • Planate
  • Fungi
  • Protists
  • Prokaryotae
43
Q

Define molecular phylogeny.

A

Using the sequence of DNA or RNA bases, sequence of amino acids in a protein, or structure of cell membranes to analyse evolutionary relationships and group organisms together based on shared/ similar features.

44
Q

Define phylogenetic tree.

A

A diagram that shows the evolutionary relationship between organisms based on molecular differences. They show where species shared and branched off from common ancestors.

45
Q

State the 3 domains.

A
  1. Prokaryotes
  2. Eukaryotes
  3. Archaea
46
Q

How did Woese come up with these domains?

A

Woese used molecular phylogeny (sequenced the RNA of bacteria) and found that there were differences between the bacteria and methanogens such as different RNA sequences, methanogens had no peptidoglycans in their cell walls, methanogens had different membrane lipids. Therefore, the methanogens were placed in a different group - archaea.

47
Q

Describe the process of critical evaluation.

A
  • Scientists communicate their research to the scientific community by publishing their findings in scientific journals and conferences.
  • Other scientists will then critically evaluate the evidence to ensure that is valid through peer review.
  • Other scientists repeat the experiments to check their reliability and validity. The theory may or may not be accepted by the scientific community.
48
Q

Define in-situ conservation.

A

When species are protected on the site of the threatened species and also includes protecting ecosystems and maintaining habitats.

49
Q

Define ex-situ conservation.

A

When species are protected away from the site of the threatened species. Populations can be supported in zoos + conservation centres.

50
Q

How do zoos use captive breeding programs to conserve rare species?

A
  • increasing population numbers of species at risk of extinction
  • protecting animals from predators/ poachers
  • Move animals between zoos and use studbooks to keep records of breeding and to maintain/ increase genetic diversity.
  • DNA profiling/ sequencing to monitor genetic diversity
  • Breeding can involve use of IVF, artificial insemination or surrogates.
51
Q

How do zoos use reintroduction programmes to conserve rare species.

A
  • Carefully select habitats/ reserves to release animals into
  • Preparing animals for reintroduction - need to reinforce wild behaviour
  • Raise awareness and educate local population to protect animals
52
Q

What is genetic drift?

A

Occurs in small populations and some alleles may not be passed onto offspring/ future generations and can be lost from a population. Allele frequency changes over time.

53
Q

What is inbreeding?

A

When closely related individuals interbreed/ reproduce. The offspring are likely to become homozygous recessive for more harmful recessive alleles and and can show inbreeding depression e.g. less fertile. Inbreeding depression affects small populations.

54
Q

What are the roles of a seedbank?

A
  • Storage of many seeds from each plant species to help conserve endangered species, conserve genetic diversity, protect plants from drought etc. Seeds may also contain alleles with medicinal properties
  • To conduct scientific research into seed storage, germination conditions
  • To work with governments to safeguard threatened species, they rely on local knowledge to identify seeds.
  • Educate people about importance of conserving plants.
55
Q

How are seeds prepared for storage and stored?

A

Seeds are:
* cleaned and dried
* sterilised to kill microorganisms which can cause decay
* x-rayed to make sure they are viable
* stored at -20 cold and dry conditions to prevent germination
* subjected to germination checks every 10 years.

56
Q

Describe the adavantages of storing seeds rather than plants.

A
  • seeds are more likely to survive for a longer time
  • seeds can be frozen but plants cannot
  • seeds are small so take up less space and more can be stored so greater genetic diversity
  • seeds need less maintenance so it is cheaper to store them than plants

A Level Biology Edexcel A (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions