4.1.3 - CLASSIFICATION AND EVOLUTION

Question 1

List the taxonomic hierarchy in order, starting at the top

Answer 1

Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species

Question 2

What are the five kingdoms? And give an example of each

Answer 2

Prokaryotae - bacteria
Protocista - algae
Fungi - moulds, yeasts, mushrooms
Plantae- mosses, ferns, flowering plants
Animalia - molluscs, insect, reptiles, birds, mammals

Question 3

What are the general features of the Prokaryotae kingdom?

Answer 3

• Unicellular
• no nucleus
• less than five micrometers

Question 4

What are the general features of the Protocista kingdom?

Answer 4

• eukaryotic cells
• usually live in water
• single-celled or simple multicellular organisms

Question 5

What are the general features of the Fungi kingdom?

Answer 5

• eukaryotic
• chitin cell wall
• saprotrophic (absorb substances from dead or decaying organisms)
• single-celled or multicellular organisms

Question 6

What are the general features of the Plantae kingdom?

Answer 6

• eukaryotic
• multicellular
• cellulose cell walls
• can photosynthesise
• autotrophic (produce their own food)

Question 7

What are the general features of the Animalia kingdom?

Answer 7

• eukaryotic
• multicellular
• no cell walls
• heterotrophic (consume plants and animals)

Question 8

How is an organism’s scientific name created using the binomial system?

Answer 8

• first part is the Genus (capital letter)
• second part is the species (lower case letter)

e.g. humans - Homo sapiens
Names are always written in italics or underlined if handwritten

Question 9

What is phylogeny?

Answer 9

The study of the evolutionary history of groups of organisms

Question 10

What does a phylogenic tree show?

Answer 10

The relationship between members of a family of species

Question 11

What evidence were the first classification systems solely based on?

Answer 11

Early classification systems only used observable features (things you can see) to place organisms into groups (e.g. whether they lay eggs, can fly)

Question 12

What is a disadvantage of basing early classification systems on observable features?

Answer 12

Scientists don’t always agree on the relative importance of different features and groups based solely on physical features may not show how related organisms are

Question 13

What other evidence is there showing how similar organisms are

Answer 13

• Observable features AND other evidence
• Molecular evidence - similarities in proteins and DNA
• Embryological evidence - similarities in the early stages of an organism’s development
• Anatomical evidence - similarities in structure and function of different body parts
• Behavioural evidence - the similarities in behaviour and social organisation of organisms

Question 14

What does new technology mean for new discoveries?

Answer 14

New technologies (e.g. new DNA techniques + better microscopes) can result in new discoveries being made and the relationships between organisms being clarified
Scientists can share their new discoveries in meetings and scientific journals. How organisms are classified is continually revised to take account of any new findings that scientists discover

Question 15

Describe one way in which scientists could use molecular evidence to determine how closely gibbons are related to humans.

Answer 15

Scientists can compare the sequence of DNA bases between humans and gibbons

Question 16

Describe three differences between organisms in the Bacteria and Archaea domains

Answer 16

The enzyme RNA polymerase is different in Bacteria and Archaea
Archaea have similar histones to Eukarya, and not Bacteria
The bonds of lipids in cell membranes of Bacteria and Archaea are different

+ development and composition of flagella are also different

Question 17

What is variation?

Answer 17

The differences that exist between individuals. Every individual organism is unique (even clones - like identical twins - show variation)

Question 18

What is continuous variation?

Answer 18

When the individuals in a population vary within a range - there are no distinct categories. E.g. humans can have any height within a range (139cm, 175cm, 185.9cm, etc) not just tall or short

Question 19

What is discontinuous variation?

Answer 19

When there are two or more distinct categories - each individual falls into only one of these categories, there are not intermediates

E.g. blood group in animals, plant colour and seed shape

Question 20

Explain how variation can be caused by genes.

Answer 20

• Different species have different genes
• Individuals of the same species have the same genes, but different versions (alleles)
• The genes and alleles of an organism is its genotype
• The differences in genotype result in variation in phenotypes - the characteristics displayed by an organism
• Examples of variation caused only by genetic factors include blood group in humans and antibiotic resistance in bacteria
• You inherit your genes from your parents. This means variation caused by genetic factors is inherited

Question 21

Explain how variation can be caused by the environment.

Answer 21

• Variation can be caused by differences in the environment, e.g. climate, food, lifestyle
• Characteristics controlled by environmental factors can change over an organism’s life
• Examples of variation caused only by environmental factors include accents and whether people have pierced ears

Question 22

Explain how variation can be caused by both genes and the environment.

Answer 22

• Genetic factors determine the characteristics an organism’s born with, but environmental factors can influence how some characteristics develop
• e.g. height - genes determine how tall an organism can grow (e.g. tall parents tend to have tall children) but diet or nutrients can accept how tall an organism actually grows
• e.g. flagellum - genera determine if a microorganism can grow a flagellum, but some will only start to grow them in certain environments (e.g. if metal ions are present)

Question 23

What is convergent evolution

Answer 23

The process whereby organisms that are not closely related independently evolve to have similar features as a result of having to adapt to similar environments

Question 24

Define adaptation

Answer 24

Variations or characteristics that enhance the survival of an organism in an environment

Question 25

What are the types of adaptation

Answer 25

• Physiological
• Anatomical
• Behavioural

Question 26

Define physiological adaptation

Answer 26

Biological processes within the organism

Question 27

Define anatomical adaptation

Answer 27

Structural or physical features

Question 28

Define behavioural adaptation

Answer 28

The way an organism behaves

Question 29

Define ecological niche

Answer 29

The match of a species to a specific environmental condition

Question 30

What is interspecific variation

Answer 30

• variation between species

e.g. the lightest species of bird is the bee hummingbird, which weighs approx. 1.6 g on average. Heaviest bird is ostrich, which can weigh up to 160 kg (x 100000)

Question 31

What is intraspecific variation?

Answer 31

• Variation within a species

e.g. individual European robins weigh between 16g and 22g and show some variation in many other characteristics including length, wingspan, colour + beak size