diversity and classification C

Question 1

what is a species

Answer 1

A group of organisms that can (interbreed to) produce fertile offspring

Question 2

Suggest why 2 different species are unable to produce fertile offspring

Answer 2

-Different species have different chromosome numbers → offspring may have odd chromosome number
-So homologous pairs cannot form → meiosis cannot occur to produce gametes

Question 3

what is a hierarchy

Answer 3

-smaller groups placed within larger groups
-no overlap between each group

Question 4

groups are called…

Answer 4

taxa

Question 5

state the hierarchy

Answer 5

-domain
-kingdom
-phylum
-class
-order
-family
-genus
-species

Question 6

How is each species universally identified?

Answer 6

A binomial consisting of the name of its genus and species, eg. Homo sapiens

Question 7

Suggest an advantage of binomial naming

Answer 7

Universal so no confusion as many organisms have more than one common name

Question 8

what is phylogenetic classification

Answer 8

-arranges species into groups in the above hierarchy based on evolutionary relationships
-shows how closely related species are by looking at common ancestors

Question 9

what is courtship behaviour

Answer 9

-behaviour that organisms carry out to attract a mate
-specific to a particular species
-can be used to classify species

Question 10

Explain why courtship behaviour is a necessary precursor to successful
mating

Answer 10

● Allows recognition of members of same species → so fertile offspring produced
● Allows recognition / attraction of opposite sex
● Stimulates / synchronises mating / production / release of gametes
● Indicates sexual maturity / fertility
● Establishes a pair bond to raise young

Question 11

what are simple courtship behaviours

Answer 11

-releasing a chemical
-using sound
-visual displays

Question 12

what are complex courtship behaviours

Answer 12

-dancing
-building

Question 13

two ways to classify using DNA/ Proteins

Answer 13

-Genome sequencing=
. Compare the order of base sequence of whole genome of different species
. Higher % match = more closely related e.g. humans and chimps = 96%
-Immunology=
. tertiary structure of protein tells us about sequence of DNA
.If same antibody binds to a specific antigen then it is closely related

Question 14

how are gene technologies used to assess genetic diversity ?

Answer 14

comparing the base sequence of DNA,base sequence of mRNA or amino acid sequence of the proteins encoded by DNA and mRNA

Question 15

what are the advantages of using gene technologies rather than traditional methods to assess genetic diversity in a population?

Answer 15

-give more accurate estimates of genetic diversity and make comparisons of genetic diversity easier to carry out

Question 16

what is biodiversity

Answer 16

● Variety of living organisms (species, genetic and ecosystem diversity)
● Can relate to a range of habitats, from a small local habitat to the Earth

Question 17

What is a community?

Answer 17

All populations of different species that live in an area.

Question 18

what is a habitat?

Answer 18

is the place where an organism lives e.g. field

Question 19

What is species richness?

Answer 19

A measure of the number of different species in a community

Question 20

What does an index of diversity do?

Answer 20

Describes the relationship between:
1. The number of species in a community (species richness)
2. The number of individuals in each species (population size

Question 21

Suggest why index of diversity is more useful than species richness

Answer 21

● Also takes into account number of individuals in each species
● So takes into account that some species may be present in small or high numbers

Question 22

Describe how index of diversity values can be interpreted

Answer 22

● High → many species present (high species richness) and species evenly represented
● Low → habitat dominated by one / a few species

Question 23

Explain how some farming techniques reduce biodiversity

Answer 23

*Removal of woodland and hedgerows, monoculture, use of herbicides to kill weeds=
● Reduces variety of plants
● So fewer habitats and niches
● And less variety of food sources
*use of pesticides=
●Predator population of pest decreases

Question 24

Explain the balance between conservation and farming

Answer 24

● Conservation required to increase biodiversity
● But when implemented on farms, yields can be reduced, reducing profit for farmers
= Eg. by reducing land area for crop growth, increasing competition, increasing pest population
● To offset loss, financial incentives / grants are offered

Question 25

How can genetic diversity within or between species be measured?

Answer 25

● Comparing frequency of measurable or observable characteristics
● Comparing base sequence of DNA
● Comparing base sequence of mRNA
● Comparing amino acid sequence of a specific protein encoded by DNA and mRNA

Question 26

Explain how comparing DNA, mRNA and amino acid sequences can indicate
relationships between organisms within a species and between species

Answer 26

● More differences in sequences → more distantly related / earlier common ancestor
● As mutations (change in DNA base sequences) build up over time
● More mutations cause more changes in amino acid sequences

Question 27

Explain the key considerations in quantitative investigations of variation
within a species

Answer 27

● Collect data from random samples (use a random number generator) → removes bias
● Use large sample size (or sample until stable running mean) → representative of whole population
● Ethical sampling (where applicable) → must not harm organism / allow release unchanged
● Calculate a mean value of collected data and standard deviation of that mean
● Interpret mean values and their standard deviations (S.D