Classification and Evolution (4.2.2)

Question 1

Why do scientists classify organisms?

Answer 1

To identify species
A clearly defined system allows the species an organism belongs to be easily identified.

To predict characteristics
If a number of individuals in a group have a specific characteristic, it’s likely that another species in the group will have the same characteristic.

To find evolutionary links
Species in the same group probably share characteristics as they have evolved from a common ancestor.

Question 2

What is phylogeny?

Answer 2

The study of the evolutionary history of groups of organisms.

Question 3

How have classification systems changed?

Answer 3

Once based on observable features.

Now includes:

Molecular evidence
Similarities in parts of DNA base sequences of genes.
Similarities in the sequence of amino acids in proteins. e.g. Cytochrome C - a short protein found in many species.

Embryological evidence (similarities in the early stages of development)

Fossil evidence

Question 4

How does the 3 domain system differ from the 5 kingdom system?

Answer 4

The 5 kingdoms were Prokaryotae, Protocista, Fungi, Plantae, Animalia

The Prokaryotae kingdom is now separated into Bacteria and Archaea domains.

Question 5

What observations were used in the original classification of organisms?

Answer 5

Anatomical e.g. number of legs

Behavioural e.g. whether an organism lives in groups

Question 6

What evidence led to the reclassification of Prokaryotae into two domains?

Answer 6

Molecular Evidence
RNA Polymerase is different in Bacteria and Archaea
Archaea, but not bacteria, have similar histones to Eukarya

Cellular Evidence
The bonds of the lipids in the cell membranes of Bacteria and Archaea are different.
The development and composition of flagellar are different.

Question 7

What two groups are used to define interactions between and within species.

Answer 7

Interspecific - Between species e.g. Robin and an Ostrich

Intraspecific - Within species e.g. Scarlet Robin and the European Robin

Question 8

Variation can be organised into two types. What are they? Provide examples for each.

Answer 8

Continuous - Individuals in a population that vary within a range,

Animals - Height / Weight / Cow Milk Yield

Plants - Surface area of leaves / Mass of seeds from a flower head

Microorganisms - Width / Length

Discontinuous - When there are two or more distinct categories.

Animals - Blood Group

Plants - Colour / Seed Shape

Microorganisms - Antibiotic resistance / Pigment production

Question 9

What can factors can cause variation?

Answer 9

Genetic factors

Environmental factors

Both

Question 10

Explain how genetic variation occurs.

Answer 10

Mutation - changes in the sequences of genes in DNA

Sexual reproduction - the creation of new combinations of genes. Independent assortment and crossing over.

Question 11

An individual’s observable traits, such as height, eye colour, and blood type is called what?

Answer 11

Phenotype

Question 12

What is an environmental factor?

Provide three examples of environmental factors.

Provide two examples of environmental variation.

Answer 12

Any factor that influences living organisms.

Climate
Diet
Culture and lifestyle

Accents
Pierced ears

Question 13

Genetic and environmental factors can influence how some characteristics develop.

Provide two examples.

Answer 13

Height - Genes determine how tall an organism can grow, but diet and nutrient availability can affect this.

Flagellum - Genes determine if a microorganism can grow a flagellum, but some will only grow in certain environments.

Question 14

What are adaptations?

Answer 14

Adaptions are changes to an organism that increase its chances of survival and reproduction.

Question 15

How does calculating mean help when investigating variation?

Answer 15

It can show if there is variation between samples.

e.g. Height of a species of a tree in different woodlands.

Question 16

Mean

Most samples include values on either side of the mean.

What sort of graph can you expect to see?

What do you call this?

Answer 16

Bell-shaped graph

Normal distribution

Question 17

How do you calculate standard deviation?

Answer 17

Question 18

What does the Spearman’s rank correlation coefficient show?

Answer 18

Whether the two variables are related, and if so, how strongly they are related.

Question 19

Before investigating correlations, what should you come up with and what does it tell you?

Answer 19

Null hypothesis.

There is no correlation between the factors you are investigating.

Question 20

Name, and give examples of three types of adaptations.

Answer 20

• *Behavioural**
• how an organism acts*

Possums play dead to increase their chance of survivial.
Scorpions dance before mating to attract a mate of the same species.

• *Physiological**
• processes inside an organism’s body*

Brown bears hibernate to lower their metabolism over winter to conserve energy.
Some bacteria produce antibiotics to kill other species of bacteria.

• *Anatomical**
• structural features of an organism’s body*

Otters have a streamlined shape. Easier to glide through water. Easier to catch prey and evade predators.
Whales have a thick layer of blubber. Keeps them warm in the sea. Increases chances of survival when food is scarce.

Question 21

Give an example of convergent evolution.

Answer 21

Marsupial and placental moles.

Evolved on different continents.

Live in the same conditions (underground):

1 - Small/non-existent eyes

2 - No external ears to keep a streamlined head

3 - Claws, specialised in digging

4 - Tube shaped body and cone-shaped head which makes it easier to push through sand or soil

Question 22

What was Darwin’s theory of evolution by natural selection?

(5 points)

Answer 22

Individuals within a population show variation in their phenotypes.

Predation, disease and competition create a struggle for survival.

Individuals with better adaptations are more likely to survive and pass on those adoptions.

Over time, the population with advantageous adaptations increases.

Over generations, favourable adaptations become more common in the population.

Question 23

Give a brief summary of Darwin and Wallace’s interactions.

Answer 23

Darwin read a geology book about fossils being evidence of animals living millions of years ago.

Darwin used observations of finches to identify adaptations that correlated to different food sources on the various Galapagos Islands.

Alfred Wallace sent his own independent observations to Darwin for peer review and they presented a joint presentation.

Question 24

What sources do scientists use to study the process of evolution?

Answer 24

Palaeontology - the study of fossils and fossil records

Comparative anatomy - the study of similarities and differences between organisms’ anatomy

Comparative biochemistry - similarities and differences between the chemical makeup of organisms

Question 25

What are the implications of pesticide resistance for humans?

Answer 25

Crop infestations with pesticide-resistant insects are harder to control.

Farmers may have to use broader pesticides that kill beneficial insects.

A population of insects resistant to all pesticides could evolve.

New pesticides need to be produced which costs time and money.

Question 26

What are the implications of drug resistance for humans?

Answer 26

Infections caused by drug-resistant microorganisms are harder to control.

It costs time and money to create new drugs.

Question 27

List the unicellular kingdoms.

How do Fungi, Plantae and Animalia store food?

What are two differences between fungi and plantae?

Answer 27

Prokaryote, Protoctista, Fungi (can be multicellular)

Glycogen, Starch, Glycogen

Fungi - no chlorophyll, saprotrophic / Plantae - Autotropic

Question 28

What are the advantages of phylogenic classification over the Linnaean system?

Answer 28

Shows evolutionary relationships that are not obvious when looking at characteristics.

A continuous tree so organisms do not have to be forced into groups.

It is clear where what the evolutionary position of a group is.

Question 29

List three important facts about fossils.

Answer 29

The sequence in which fossils are found match their ecological links. e.g. plants existed before animals.

Similarities in the anatomy of fossil organisms can help identify ancestors

Fossil records are not complete because of soft body creatures decomposing, and earth movements destroying them.

Question 30

What is a homologous structure?

Answer 30

One that appears superficially different but has the same underlying structure.

They provide evidence for divergent evolution. Where closely related species diversify and adapt to new habitats.

Question 31

What is comparative biochemistry?

Answer 31

Similarities and differences in proteins and molecules.

e.g. Changes in base sequences of DNA or the order of amino acids.

Question 32

What are 4 examples of anatomical adaptations?

Answer 32

Body covering - hair, scales, spines.

Camouflage

Teeth e.g. sheep have continually growing molars for munching.

Mimicry - copying the appearance of another organism to fool predators.

Question 33

Give 3 examples of behavioural adaptations.

Answer 33

Survival - playing dead

Courtship - scorpions dancing, peacocks flashing

Seasonal - migration / hibernation

Question 34

What two categories do behavioural adaptations fall into?

Answer 34

Innate behaviour - spiders build webs

Learned - otters using stones as hammers

Question 35

Give three examples of physiological adaptations.

Answer 35

Poison production - plants protecting themselves / venom in reptiles

Antibiotic production (bacteria killing other bacteria)

Water holding - cacti / water-holding frog

Question 36

All organisims are exposed to ______ ______ .

Answer 36

selection pressures