Topic 4.1

Question 1

Biodiversity

Answer 1

Variety of living organisms in an area

Question 2

Species diversity

Answer 2

Number of different species (species richness) and the abundance of each species in an area (species abundance)

Question 3

Genetic diversity

Answer 3

Variation of alleles within a species

Question 4

Endemism

Answer 4

When a species is unique to a single place (isn’t naturally found anywhere else in the world)
-> endemic species are very vulnerable to extinction due to their limited range

Question 5

Variety of life

Answer 5

Natural selection leading to adaptation and evolution has increased biodiversity on earth over time, but human activities are reducing species diversity
-> some of these human activities include:
. Hunting
. Deforestation
. Climate change
. Agriculture
. Overexploitation

Question 6

Hábitat

Answer 6

Place where an organisms live
-> it is important to measure species adversity in order to compare different habitats or to study how a habitat has changed over time

Question 7

Measuring species diversity: 2 ways

Answer 7

1. Calculate species richness -> count number of different species in an area
2. Calculate species abundance -> count number of different species and the number of individuals in each species and then use index of diversity (D)

Question 8

Sampling

Answer 8

1. Choose area to sample randomly -> makes results more reliable (less bias)
2. Count number of individuals of each species in sample area
   . For plants: use a quadrant
   . For flying insects: use a sweep net
   . For ground insects: use a pitfall trap
   . For aquatic animals: use a net
3. Repeat the process as many times as possible -> makes results more representative of whole habitat
4. Use results to estimate total number of individuals or total number of different species (species richness) in the habitats studied

Question 9

Genetic diversity within a species:

Answer 9

Individuals of the same species vary because they have different alleles, so genetic diversity within a species refers to the variety of alleles in the gene pool

Question 10

Genetic diversity within a species: gene pool

Answer 10

Complete set of alleles in a species (or population) - the greater the gene pool, the greater the genetic diversity
-> its importante to measure genetic diversity to investigate how populations of the same species show different diversity or to show how the genetic diversity of a population change over time

Question 11

Measuring genetic diversity: phenotype

Answer 11

The larger the number of different phenotypes within a species, the greater the genetic diversity (greater variety in alleles present in species)

Question 12

Measuring genetic diversity: genotype

Answer 12

The larger the number of different alleles present within a species, the greater the genetic diversity.
-> to look at similarities and differences of alleles within a species you can sequence DNA of individuals of the same species

Question 13

Heterozygosity index

Answer 13

Heterozygotes are individuals that have two different alleles at a particular locus, and a higher proportion of heterozygotes in a population means that the population has a greater genetic diversity
-> this proportion of heterozygotes in the population can be found with the heterozygosity index (H)

Question 14

Niche

Answer 14

Role of a species within its habitat -> each species will have its own niche
-> this includes:
. It’s interactions with other living organisms
. It’s interactions with the non-living environment
-> if two species try to occupy the same niche they will compete with each other, and one species will be more successful than the other until only one of the species is left

Question 15

Adaptation

Answer 15

Features which increase the organisms chances of survival and reproduction
-> these features include
. Behavioural adaptations
. Physiological adaptations
. Anatomical adaptations
- Adaptations become more common in populations of species because of evolution by natural selctio

Question 16

Organism adaptations to their niche: behavioural adaptations

Answer 16

Ways an organism acts that increase its chances of survival
Examples:
-> possums ‘play dead’ to avoid being detected by predators and attract prey
-> scorpions dance before mating to attract the best partner of species

Question 17

Organism adaptations to their niche: physiological adaptations

Answer 17

Processes inside an organisms body that increase its chances of survival
Example:
-> brown bears hibernate in winter to slow down their metabolism to conserve energy as there’s less prey available

Question 18

Organism adaptations to their niche: anatomical adaptations

Answer 18

Structural features of an organisms body that increase its chances of survival
Example:
-> whales have thick layer of blubber to keep them warm in cold water where they can catch prey

Question 19

Evolution: mutations

Answer 19

These can introduce new alleles into a population causing individuals within a population to show their variation in their phenotypes
-> some of these alleles determine phenotypes that can make the individual more likely to survive

Question 20

Evolution: selection pressure

Answer 20

These are changes in the environment that create struggle for survival

Question 21

Evolution: competition

Answer 21

Individuals without advantageous allies don’t survive so there’s fewer individuals and less competition for resources

Question 22

Evolution: survival and reproduction

Answer 22

Individuals with better adaptations are more likely to survive, reproduce and pass on their advantageous alleles to offspring

Question 23

Evolution: over time

Answer 23

Number of individuals with advantageous alleles increase

Question 24

Evolution: over generations

Answer 24

Evolution happens as frequency of the advantageous alleles in the population increases and the favourable adaptations become more common

Question 25

Speciation

Answer 25

Development of new species -> species: group of similar organisms that can reproduce to give fertile offspring -> speciation occurs when populations of the same species become reproductively isolated due to random mutations or geographical isolation which prevent individuals from successfully breeding together

Question 26

Random mutations

Answer 26

Random mutations can produce new alleles, new phenotypes, and so the following changes - seasonal changes - mechanical changes - behavioural changes

Question 27

Random mutations: seasonal changes

Answer 27

Individuals from the same population develop different flowering or mating seasons (become sexually active at different times of the year)

Question 28

Random mutations: mechanical changes

Answer 28

Structural changes to the genitalia in some individuals prevent them from successfully mating with main population

Question 29

Random mutations: behavioural changes

Answer 29

Group of individuals develop courtship rituals that aren’t attractive to main population

Question 30

Geographical isolation

Answer 30

1. Population is divided by a physical barrier 2. There's different conditions and selection pressures on either side of the barrier 3. Natural selection takes place due to the different environments on either side to make advantageous characteristics more common -> Different characteristics will be advantageous so allele frequencies will change in each population -> Mutations will take place independently in each population changing the allele frequencies 4. Different allele frequencies will make the populations more genetically distinct and will lead to different phenotype frequencies arising on each side 5. New species is formed eventually as they aren't able to reproduce with one another to produce fertile offspring

Question 31

Allele frequency

Answer 31

How often an allele occurs in a population -> The frequency of an allele in a population changes over time due to gene mutations and this leads to evolution -> Hardy-Weinberg equations can be used to calculate allele frequencies and to see if a population has changed over time

Question 32

Hardy-Weinberg principle

Answer 32

Predicts that the frequencies of alleles in a population won’t change from one generation to the next -> this is only true under certain conditions: . Large population . No immigration . No mutations . No natural selection . Random mating -> if allele frequencies do change in a large population then immigration, emigration, mutations or natural selection have happened

Question 33

Hardy-Weinberg equations

Answer 33

P + q = 1 (P: frequency of dominant allele) (Q: frequency of recessive allele) P^2 + 2pq + q^2 = 1 (P^2: frequency of homozygous dominant genotype) (2pq: frequency of heterozygous genotype) (Q^2: frequency of homozygous recessive genotype)

Question 34

Taxonomy

Answer 34

Science of classification which involves naming organisms and organising them into groups based on similarities and differences

Question 35

Classification

Answer 35

Classification of organisms is based in their phenotypes, genotypes and how related they are to . Early classification systems: only used observable phenotypes to place organisms into groups . New technologies: organisms are classified based on their DNA base sequence

Question 36

The 8 taxonomic groups

Answer 36

. Domain . Kingdom . Phylum . Class . Order . Genus . Species

Question 37

Binomial system

Answer 37

First the genus with a capital letter and then the species with lower case in italics

Question 38

What are the 5 kingdoms

Answer 38

Prokaryotes, protoctista, fungi, plantae, animalia

Question 39

Prokaryotes

Answer 39

Prokaryotic cells, unicellular, no nucleus, less than 5 nanometres Eg. Bacteria

Question 40

Protoctista

Answer 40

Eukaryotic cells, usually live in water, single-celled or simple multicellular organisms Eg. Algae, Protozoa

Question 41

Fungí

Answer 41

Eukaryotic cells, chitin cell walls, saprotrophic Eg. Moulds, yeast, mushrooms

Question 42

Plantae

Answer 42

Eukaryotic cells, multicellular, cellulose cell walls, can photosynthesise, contain chlorophyll, autotrophic Eg. Mosses, ferns, flowering plants

Question 43

Animalia

Answer 43

Eukaryotic cells, multicellular, no cell walls, heterotrophic

Question 44

What is done to new scientific data

Answer 44

New data is evaluated by other scientists to change the classification system or how an organisms is classified -> the validity of of the research is checked through the study method/design, and then the research is published in scientific journals where its peer reviewed beforehand

Question 45

New three domain classification system proposed

Answer 45

This has been proposed after new data on molecular phylogeny . Phylogeny: study of the evolution of organisms . Molecular phylogeny: study of similarities and differences in DNA and proteins between different organisms

Question 46

Old classification VS new classification system

Answer 46

Old classification: all organisms were directly classified into 5 kingdoms New classification: all organisms are first classified into 3 domains . Organisms in prokaryote kingdom are separated into two domains: Bacteria and Archaea . The other four kingdoms are placed into the third domain: Eukaryota

Question 47

Conservation

Answer 47

Protection and management of endangered species -> methods of conservation of endangered species to prevent loss of genetic and biodiversity

Question 48

Methods for conservation of endangered species

Answer 48

. Seed banks . Captive breeding programmes . Reintroduction programmes . Zoos . Education . Scientific research

Question 49

seed banks

Answer 49

Store seeds from endangered plants -> these conserve genetic diversity by storing a range of seeds with different alleles and different phenotypes which increases survival chances

Question 50

Seed banks: conditions required

Answer 50

. Collect seeds, sterilise them and dry them out . Store in a cool (-20 degrees) and dry place -> prevents from germinating

Question 51

Advantages of seed banks

Answer 51

. Cheaper to store seeds than fully grown plants . Larger number of seeds can be stores as they need less space . Less work required to take care of seeds . Seeds can be stored anywhere as long as its cool and dry . Seeds are less likely to be damaged by disease, vandalism or natural disorders

Question 52

Disadvantages of seed banks

Answer 52

. Testing seeds for viability is expensive and time consuming . Very expensive to store all types of seeds and test them regularly for viability . Hard to collect seeds from species in remote collections

Question 53

Zoos and captive breeding

Answer 53

Zoos can breed endangered species in controlled environments to increase their numbers

Question 54

Zoos and captive breeding: captive breeding problems

Answer 54

. Difficult to recreate natural environment of organisms in a zoo . Inbreeding depression -> decreases reproduction and chances of survival . Ethical concerns surrounding keeping wild animals in captivity

Question 55

Reintroduction programmes

Answer 55

Organisms from zoos and seed banks can be reintroduced into the wild which increases the number of these organisms in the wild, helping to conserve numbers or bring them back from the brink of extinction

Question 56

Reintroduction programmes: advantages

Answer 56

. Increases food availability . Increases population and biodiversity . Habitats develop

Question 57

Reintroduction programmes: disadvantages

Answer 57

. Organisms act differently in the wild due to being raised in a zoo . New diseases . New competition

Question 58

Scientific research: seed banks advantages and disadvantage

Answer 58

Advantages: . Provide knowledge of conditions required for plant growth . Endangered species can be grown for medical research Disadvantages: . Data is limited to small, interbred populations which aren’t representative of wild plants

Question 59

Scientific research: zoos advantages and disadvantage

Answer 59

Advantages: . Increases knowledge about the behaviour, physiology and nutritional needs of animals . Easier to investigate animals in controlled environment Disadvantages: . Animals in captivity may act differently to animals in wild

Question 60

Education

Answer 60

Educating people about endangered species and reduced biodiversity helps to raise awareness and interest in conserving biodiversity . Zoos: let people get close to organisms increasing their enthusiasm for conservation work . Seed banks: provide training and set up local seed banks all around the world