Classification and Evolution

Question 1

What are the 8 groups taxonomic groups?

Answer 1

Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species

Question 2

Why do scientists classify organisms?

Answer 2

• to identify species
• to predict characteristics
• to find evolutionary links

Question 3

What are the 3 domain systems?

Answer 3

Archae
Bacteria
Eukarya

Question 4

What is the definition of a species?

Answer 4

A species is defined as a group of organisms that are able to reproduce to produce fertile offspring.

Question 5

Why are cross species animals infertile ?

Answer 5

Because they have an odd number of chromosomes so they can’t produce sperm or eggs

Question 6

What is the binomial nomenclature?

Answer 6

naming system that allows scientists worldwide to discuss organisms despite different languages

Question 7

how does the binomial nomenclature work?

Answer 7

all species are given a name consisting of 2 parts:

• the 1st part indicates the organisms genus, and is always written with a capital letter
• the 2nd part indicates the organisms species. it is called the specific name. it is NOT written with a capital letter

Question 8

Who found the 5 kingdom classification system?

Answer 8

Robert Whittaker

Question 9

what are the 5 kingdoms?

Answer 9

Prokaryotae (bacteria)
Protoctist (the unicellular eukaryotes)
Fungi (e.g. yeasts, moulds, and mushrooms)
Plantae (the plants)
Animalia (the animals)

Question 10

how can scientists find how species are related?

Answer 10

by comparing the similarities in the DNA and proteins of different species, scientists can discover the evolutionary relationships between them

Question 11

what is phylogeny?

Answer 11

phylogeny is the name given to the evolutionary relationships between organisms. it reveals which group a particular organism is related to, and how closely related these organisms are

Question 12

what are some of the advantages of phylogeny?

Answer 12

• phylogeny can be done without reference to Linnaen classification. e.g. Dolphin and fish have many of the same characteristics, however phylogeny confirms a dolphins classification as a mammal
• phylogeny produces a continuous tree whereas classification requires discrete taxonomical groups

Question 13

what is evolution?

Answer 13

evolution is the theory that describes the way in which organisms evolve, or change, over many years as a result of natural selection

Question 14

what is the process of natural selection?

Answer 14

• each species shows variation
• there is competition within each species for food, living space, water, mates etc (selection pressures - things organisms compete for)
• the ‘better adapted’ members of the species are more likely to survive
• the survivors will pass on their advantageous alleles to their offspring, which will give them a better chance at survival, meaning the alleles are continually passed down generations

Question 15

what are some sources of evidence for evolution?

Answer 15

• -palaeontology - the study of fossils and the fossil record
• -comparative anatomy - the study of similarities and differences between organisms’ anatomy
• -comparative biochemistry - similarities and differences between the chemical makeup of organisms 0

Question 16

what is an anatomical adaptation?

Answer 16

physical features (internal and external) 
example: body covering such as fur or feathers

Question 17

what is a behavioural adaptation?

Answer 17

the way an organism acts. these can be inherited or learnt from their parents.
example: migration or hibernation

Question 18

what is a physiological adaptation?

Answer 18

processes that place inside an organism

example: poison production

Question 19

what is a homologous structure?

Answer 19

a homologous structure is a structure that appears superficially different (and may perform different functions) in different organisms, but has the same underlying structure.

Question 20

what type of evolution do homologous structures provide evidence for?

Answer 20

divergent evolution

Question 21

what is divergent evolution?

Answer 21

when species sharing a common ancestry become come more distinguished due to differential selection pressures which gradually leads to speciation over an evolutionary time period

Question 22

what is convergent evolution?

Answer 22

convergent evolution takes place when unrelated species begin to share similar traits

Question 23

what is interspecific variation?

Answer 23

the type of variation between members of different species

Question 24

what is intraspecific variation?

Answer 24

differences between organisms within a species

Question 25

what are the 2 factors that cause variation?

Answer 25

• an organisms genetic material

- the environment in which the organism lives

Question 26

what are the genetic causes of variation?

Answer 26

• alleles
• mutations
• meiosis

Question 27

what are the environmental causes of variation?

Answer 27

all organisms are affected by the environment in which they live.
an example of a characteristic that is determined purely by environmental variation is the presence of any scars on your body

Question 28

can variation be caused by environmental and genetic causes?

Answer 28

yes, in most cases variation is caused by a combination of both environmental and genetic factors.
example: if you have tall parents you have most likely inherited the genes to also grow to a tall height. however if you eat a very poor diet you may only grow to below average height

Question 29

what is an analogous structure?

Answer 29

structures that are similar in function but not necessarily similar in structure. they DO NOT derive from a common ancestor