SECTION 12: CLASSIFICATION AND EVOLUTION

Question 1

4.3.1 CLASSIFICATION BASICS
What is classifcation?

Answer 1

The act of arranging organisms into groups based on their similarities and differences
this makes it easier for scientists to identify them and to study them

Question 2

4.3.1 CLASSIFICATION BASICS
What is taxonomy?

Answer 2

Is the study of classification

Question 3

4.3.1 CLASSIFICATION BASICS
What is the curretn system of classification?

Answer 3

Domain - Did
Kingdom - King
Phylum - Philip
Class - Came
Order - Over
Family - Food
Genus - Good
Species - sandwiches

• all capitalised from domain to genus until species that is lower case

Question 4

4.3.1 CLASSIFICATION BASICS
How are the names in animals written?

Answer 4

the first part is written in a genus name and the second part to the name is a species name
and it written in either italics or underlined

Question 5

4.3.1 CLASSIFICATION BASICS
What each of the five kingdoms?

Answer 5

Animal
Plant
Fungi
Protoctist
Bacteria

Question 6

4.3.1 CLASSIFICATION BASICS
Name the key features of an animal : domain, cellular structure, How it gains energy, examples

Answer 6

Domain: Eukaryotic
Cellular strucutre: no cell wall, DNA contained within a nucleus, multicellular
How it gains energy: heterotrophic
examples: pangolin, coral polyps, tsetse fly

Question 7

4.3.1 CLASSIFICATION BASICS
Name the key features of an plant : domain, cellular structure, How it gains energy, examples

Answer 7

domain: eukarytic
cellular structure: cellulose cell wall, dna contained within a nucleus, multicellular, contains chlorophyll
how it gains energy: autotrophic
examples: mosses, ferns, flowering plants

Question 8

4.3.1 CLASSIFICATION BASICS
Name the key features of an fungi : domain, cellular structure, How it gains energy, examples

Answer 8

domain: eukaryotic
cellular structure: chitin cell wall, saprotrophic (absorbs susbtances from dead or decaying organisms), single celled or multicellular organisms
how it gains energy: saprotrophic
examples: moulds, yeast, mushrooms

Question 9

4.3.1 CLASSIFICATION BASICS
Name the key features of an protoctist : domain, cellular structure, How it gains energy, examples

Answer 9

Domain: eukaryotic
cellular structure: unicellualr or simple multicellar
how it gains energy: autotrophic and heterotrophic
example: alagae, prtozoa

Question 10

4.3.1 CLASSIFICATION BASICS
Name the key features of an bacteria : domain, cellular structure, How it gains energy, examples

Answer 10

domain: prokatyatae
cellular structure: murein cell wall, circular DNA - no nucleus, unicellular
how it gains energy: autotrophic (photo or chemo) or saprotrophic (heterotrophic)
examples: bacteria, e.coli, salmonella

Question 11

4.3.1 CLASSIFICATION BASICS
What is phylogeny and what does it tell us?

Answer 11

is the study of the evolutionary history of groups of organisms
and this tells us who’s related to whom and how closely related they are

Question 12

4.3.1 CLASSIFICATION BASICS
What is cladistics?

Answer 12

classification systems now take into account phylogeny when arranging oraganisms into groups
classifying organisms in this way is known as cladistics

Question 13

4.3.2 THE EVOLUTION OF CLASSIFICATION SYSTEMS
How were animals classified in the early years?

Answer 13

• Originally, classification was based on morphology (physical features) as they were easily observable.
• All organisms fitted into two categories: animals and plants.

Question 14

4.3.2 THE EVOLUTION OF CLASSIFICATION SYSTEMS
What are the modern techniques to classify accurately?

Answer 14

Cytochrome C
DNA
Embryology

Question 15

4.3.2 THE EVOLUTION OF CLASSIFICATION SYSTEMS
How can cytochrome C be used to classify?

Answer 15

•A protein needed for respiration so is present in all living organisms. Variations in the amino acids have resulted over time. The similarities and differences between them help establish how closely related different species is to another

Question 16

4.3.2 THE EVOLUTION OF CLASSIFICATION SYSTEMS
How can DNA be used to classify?

Answer 16

All living things have genetic material, either DNA or RNA. Analysing the differences in the base sequence helps establish how closely related one species is to another.

Question 17

4.3.2 THE EVOLUTION OF CLASSIFICATION SYSTEMS
How can embryology be used to classify?

Answer 17

Comparing the similarities and differences in the stages of embryonic development can also be used to determine how closely related organisms are

Question 18

4.3.2 THE EVOLUTION OF CLASSIFICATION SYSTEMS
How do new technologies provide evidence that can alter existing classification groups?

Answer 18

New technologies (e.g. new DNA analysis techniques, better microscopes) can result in new discoveries being made. 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 19

4.3.2 THE EVOLUTION OF CLASSIFICATION SYSTEMS
What are the three domains?

Answer 19

Bacteria
Archaea
Eukarya

Question 20

4.3.2 THE EVOLUTION OF CLASSIFICATION SYSTEMS
What is the properties of archaea?

Answer 20

Unique rRNA
Membranes contain branched hydrocarbon chains
Cells walls no peptidoglycan
Flagella (archaella)
Proteins bound to genetic material
Circular chromosome

Question 21

4.3.2 THE EVOLUTION OF CLASSIFICATION SYSTEMS
What is the properties of bacteria?

Answer 21

Unique rRNA
Membranes contain
unbranched fatty acid chains
Cells walls peptidoglycan
flagella
No proteins bound to genetic material
Circular chromosome

Question 22

4.3.2 THE EVOLUTION OF CLASSIFICATION SYSTEMS
What is the properties of eukaryotes?

Answer 22

Unique rRNA
Membranes contain
unbranched fatty acid chains
Cells walls no peptidoglycan
No flagella (most)
Proteins bound to genetic material
Linear chromosomes

Question 23

4.3.3 VARIATION
What is variation?

Answer 23

Variation is the differences that exist between individuals. Every individual organism is unique — even clones (such as identical twins) show some variation.

Question 24

4.3.3 VARIATION
What is intraspecific?

Answer 24

Variation within a species is called intraspecific variation.

Question 25

4.3.3 VARIATION What is intraspecific variation?

Answer 25

The variation between different species is called interspecific variation.

Question 26

4.3.3 VARIATION What is continuous variation?

Answer 26

Continuous variation is when the individuals in a population vary within a range of- there are no distinct categories e.g Animals • Height — humans can be any height within a range (e.g. 139 cm, 175 cm, 185.9 cm, etc.), not just tall or short — see Figure 1. Mass - humans can be any mass within a range. • Milk yield - cows can produce any volume of milk within a range.

Question 27

4.3.3 VARIATION What is discontinuous variation?

Answer 27

Discontinuous variation is when there are two or more distinct categories — each individual falls into only one of these categories, and there are no intermediates.

Question 28

4.3.3 VARIATION How genetic factors a cause of variation?

Answer 28

Different species have different genes. Individuals of the same species have the same genes, but different versions of them (called alleles). The alleles an organism has make up its genotype. The differences in genotype result in variation in phenotype — the characteristics displayed by an organism. Examples: Variation caused by genetic factors includes: • Eye colour in humans (which can be blue, green, grey, brown), • Blood type in humans (O, A, B or AB), • Antibiotic resistance in bacteria.

Question 29

4.3.3 VARIATION How environmental factors a cause of variation?

Answer 29

Variation can also be caused by differences in the environment, e.g. climate, food, lifestyle. Characteristics controlled by environmental factors can change over an organism's life.

Question 30

4.3.4 INVESTIGATING VARIATION

Answer 30

LOOK AT THE TEXTBOOK AND NOTES PAGE 278-283

Question 31

4.3.5 ADAPTATIONS What are the three types of adaptations?

Answer 31

Behavioural Physiological Anatomical

Question 32

4.3.5 ADAPTATIONS What is behavioural adaptation?

Answer 32

These are ways an organism acts that increase its chance of survival.

Question 33

4.3.5 ADAPTATIONS What is anatomical (structural) adaptation?

Answer 33

These are structural features of an organism's body that increase its chance of survival.

Question 34

4.3.5 ADAPTATIONS What is physiological adaptation?

Answer 34

These are processes inside an organism's body that increase its chance of survival

Question 35

4.3.5 ADAPTATIONS What is convergent evolution?

Answer 35

When two species evolve similar characteristics independently of one another (because they've adapted to live in similar environments) it's called convergent evolution.

Question 36

4.3.5 ADAPTATIONS Compare marsupial mammals and placental mammals

Answer 36

MARSUPIAL - Have a short gestation period (pregnancy). - Don't develop a full placenta. - Are born early in their development and climb into their mother's pouch. Here they become attached to a teat and receive milk while they continue to develop. PLACENTAL - Develop a placenta during pregnancy, which allows the exchange of nutrients and waste products between the fetus and the mother. - Have a longer gestation period. - Are born more fully developed.

Question 37

4.3.6 THE THEORY OF EVOLUTION What is Darwin’s observations?

Answer 37

Darwin's observations: 1. Organisms produce more offspring than survive. 2. There's variation in the characteristics of members of the same species. 3. Some of these characteristics can be passed on from one generation to the next. 4. Individuals that are best adapted to their environment are more likely to survive.

Question 38

4.3.6 THE THEORY OF EVOLUTION What was Darwin’s theory on natural selection?

Answer 38

• Individuals within a population show variation in their phenotypes (their characteristics). • Selection pressures (environmental factors such as predation, disease and competition) create a struggle for survival. • Individuals with better adaptations (characteristics that give a selective advantage, e.g. being able to run away from predators faster) are more likely to survive and have reproductive success — in other words, they reproduce and pass on their advantageous adaptations to their offspring. • Over time, the proportion of the population possessing the advantageous adaptations increases. " Over generations this leads to evolution as the favourable adaptations become more common in the population.

Question 39

4.3.6 THE THEORY OF EVOLUTION How to answer questions on natural selection?

Answer 39

1. There is genetic variation within the population (use the phrase 'random mutation' here and reference the organism in the question) 2. There is some form of struggle for existence - this is sometimes called a selection pressure 3. The best adapted survive - these individuals contain beneficial alleles 4. These individuals breed/reproduce 5. The next generation inherit these beneficial alleles 6. Over many generations, the allele frequency changes

Question 40

4.3.6 THE THEORY OF EVOLUTION Example - peppered moth for natural selection

Answer 40

, Peppered moths show variation in colour — there are light ones (with alleles for light colour) and dark ones (with alleles for dark colour). • Before the 1800s there were more light moths than dark moths. • During the 1800s, pollution had blackened many of the trees that the moths lived on. Dark coloured moths were now better adapted to this environment — they were better camouflaged from predators, so would be more likely to survive, reproduce and pass on the alleles for their dark colouring to their offspring. During this time the number of dark moths increased and the alleles for dark colour became more common in the population.

Question 41

4.3.6 THE THEORY OF EVOLUTION How does fossils evidence provide support for evolution?

Answer 41

Fossils are the remains of organisms preserved in rocks. By arranging fossils in chronological (date) order, gradual changes in organisms can be observed that provide evidence of evolution. Example: The fossil record of the horse shows a gradual change in characteristics, including increasing size, lengthening of the limbs and hoof development.

Question 42

4.3.6 THE THEORY OF EVOLUTION How does molecular evidence - DNA provide support for evolution?

Answer 42

The theory of evolution suggests that all organisms have evolved from shared common ancestors. Closely related species diverged (evolved to become different species) more recently. Evolution is caused by gradual changes in the base sequence of organisms A So organisms that diverged away from each other more recently should have more similar DNA, as less time has passed for changes in the DNA sequence to occur. This is exactly what scientists have found.

Question 43

4.3.6 THE THEORY OF EVOLUTION How does molecular evidence - protein and other molecules provide support for evolution?

Answer 43

In addition to DNA, the similarities in other molecules provide evidence. Scientists compare the sequence of amino acids in proteins, and compare antibodies. Organisms that diverged away from each other more recently have more similar molecules, as less time has passed for changes in proteins and other molecules to occur.

Question 44

4.3.6 THE THEORY OF EVOLUTION What was Wallace’s contribution?

Answer 44

• Alfred Russel Wallace independently developed the theory of evolution by natural selection at the same time as Charles Darwin. • Wallace wrote to Darwin explaining his ideas about natural selection. • Wallace and Darwin published a joint paper on evolution in 1858, acknowledging each other’s work. • Wallace provided evidence for natural selection through observations in the natural world. • Example of evidence: • Warning colours in species (e.g. butterflies) deter predators. • This is an advantageous adaptation that increases survival and reproduction. • Wallace and Darwin did not agree on all mechanisms, but agreed on natural selection as the main process. • Darwin became more famous because: • He published On the Origin of Species. • The book included extensive evidence and detailed explanations. • Darwin described observations from South America and the Galápagos Islands. • Wallace’s contributions were important but less recognised because Darwin’s book gained more attention.

Question 45

4.3.7 MORE ON EVOLUTION What is the evolution of pesticide resistance?

Answer 45

Pesticides are chemicals that kill pests (e.g. insects that damage crops). Scientists have observed the evolution of pesticide resistance in many species of insect.

Question 46

4.3.7 MORE ON EVOLUTION How can natural selection explain the evolution of pesticide resistance?

Answer 46

• There is variation in a population of insects. Genetic mutations make some insects naturally resistant to a pesticide. • If the population of insects is exposed to that pesticide, only the individuals with resistance will survive to reproduce. The alleles which cause the pesticide resistance will be passed on to the next generation. Over many generations, the population will evolve to become more resistant to the chemical.

Question 47

4.3.7 MORE ON EVOLUTION What is the implications of pesticide resistance for humans?

Answer 47

Crop infestations with pesticide-resistant insects are harder to control - some insects are resistant to lots of different pesticides. It takes farmers a while to figure out which pesticide will kill the insect and in that time all the crop could be destroyed. If the insects are resistant to specific pesticides (ones that only kill that insect), farmers might have to use broader pesticides (those that kill a range of insects), which could kill beneficial insects. And if disease-carrying insects (e.g. mosquitoes) become pesticide-resistant, the spread of disease could increase. A population of insects could also evolve resistance to all pesticides in use. To prevent this, new pesticides need to be produced. This takes time and costs money.

Question 48

4.3.7 MORE ON EVOLUTION What are the implications of drug resistance for humans?

Answer 48

Infections caused by drug-resistant microorganisms are harder to treat — especially if the microorganism is resistant to lots of different drugs. It can take doctors a while to figure out which drugs will get rid of the infection, and in that time the patient could become very ill or die. There could come a point where a pathogen has become resistant to all the drugs we currently use against it. To prevent this, new drugs need to be developed. This takes time and costs a lot of money.