Classification

How does courtship sequence provide evidence to support claim that the two species are (a) closely related (b) separate species

(a) similar sequence (b) additional actions in sequence for species A

Suggest two advantages of male snakes courting with longer females

1. Produce more/larger offspring 2. Better predators/fitter/more successful at gaining food/less likely to be eaten 3. More sexually mature/fertile 4. Have more food stores for offspring/eggs

Fruitflies evolving

1 Variation in beak shape present in original population; 2 No gene flow between islands/geographical isolation; 3 Selection of individuals with beaks suitable for eating small seeds on one island/selection of beak suitable for eating large seeds on another; 4 Those with the most suited beaks (survived) to reproduce/pass on their alleles/genes for beak shape; 5 Allele frequency changed on each island / populations became genetically different; 6 So that individuals from different islands unable to reproduce to produce fertile offspring;

These two species may have evolved from 1 species, explain how

1 Variation in beak shape present in original population; 2 No gene flow between islands/geographical isolation; 3 Selection of individuals with beaks suitable for eating small seeds on one island/selection of beak suitable for eating large seeds on another; 4 Those with the most suited beaks (survived) to reproduce/pass on their alleles/genes for beak shape; 5 Allele frequency changed on each island / populations became genetically different; 6 So that individuals from different islands unable to reproduce to produce fertile offspring;

Explain what caused the DNA to separate at a higher temperature.

1. Relationship is closer/more complementary bases/more base pairs; 2. More hydrogen bonds; 3. More heat energy needed (to separate bonds);

Scientists can use protein structure to investigate the evolutionary relationships between different species. Explain why KEYWORD = PROTEIN STRUCTURE! ALWAYS THINK PRIMARY STRUCTURE

1. Amino acid sequences/primary structure 2. Closer the amino acid sequence, closer the relatationship 3. Protein structure related to DNA/base sequence

Courtship behaviour

1. Attracts/recognises same species 2. Attracts/recognises mates of the opposite sex. 3. Indication of sexual maturity/fertility = synchronise mating. 4. Stimulates release of gametes. 5. Form a pair bond

Explain why it was important that they made samples of hybrid DNA from the same gene.

1. Base sequence will be similar/some bases in common; 2. These bases will bind together/hydrogen bonds/complementary pairs;

Importance of using the same gene in DNA hybridisation

1. Base sequence will be similar/some bases in common. 2. These bases will bind together/hydrogen conds/comp base pairs.

Mutations pay produce multiple alleles of a gene, explain

1. Change in base sequence 2. In different places within the gene

Describe how comparisons of biological molecules in these two species could be used to find out if they're closely related.

1. Compare DNA = look at similarities in base sequences = more bases similar = more closely related, as base sequence is the resultof DNA. 2. Compare proteins = look at similarities of amino acids. 3. DNA hybridisation - Separate DNA strands, use heat to break H bonds - Mix strands together, allow h bonds to reform - Heat up 50% marked hybrid strands - More complementary base pairs = more H bonds reform - Greater num of comp base pairs, greater num of H bonds, stronger the strand = more heat energy needed to sep the bonds. - Higher temp needed to separate strands, larger num of bases in common, more closely related. 4. Immunological comparison of proteins - Extract blood plasma from seahorse, which cont proteins - Inject this into another animal, will produce antibodies specific to antigen sites of seahorse proteins - Extract serum cont antiboides - Extract serum from animal you want to compare seahorse with - Mix these serums - Antibodies respond to corresponding antigen sites of proteins in C, response is precipitate formed - Greater num of similar antigens, more precipitate formed, more closely related. - Less precipitate = more distantly related.

Courtship Q

1. Courtship behaviour is SPECIES SPECIFIC 2. Greater the similarity in courtship behaviour, the closer the relationship between species.

Explain why biologists could use calls to investigate relationships between different species of crane

1. Courtship is species specific, allows recognition of same species 2. GREATER SIMILARITY IN CALLS, CLOSER THE RELATIONSHIP BETWEEN SPECIES.

The biologists who studied these shrimps wanted to know if the shrimps living in the cave were the same species as those living in the open. They used breeding experiments to investigate this. Describe how the biologists should carry out these breeding experiments.

1. Cross shrimps from two sites/watch courtship; 2. Breed young together/observe mating; 3. Allow 1 mark for any method of improving quality of results e.g. carry out reciprocal crosses/large number of crosses/isolate beforehand; = If same species the shrimps would breed, producing fertile young/courtship species specific

DNA hybridisation process

1. DNA from 2 species is extracted, purified, cut into pieces. 2. DNA from one species is labelled by attaching a radioactive or fluorescent marker to it, mixed with unlabelled. 3. Mixture of both sets of strands heated to separate strands (break H bonds). 4. Mixture is cooled to allow strands to combine with other strands that a have a COMPLEMENTARY SEQUENCES OF BASES (allow H bonds to reform). 5. Some of the double strands that reform = one strand from each species, hybrid strands = identified because they are 50% labelled. 6. Hybrid strands separated out, temp increased in stages. 7. At each temp, degree to which two strands are linked together is measured. 8. Relationship is closer = more complementary bases , more base pairs. 9. Therefore more H bonds linking them together in the hybrid strnad. 10. The greater the number of hydrogen bonds, the stronger the hybrid strand. 11. The more heat energy required to separate the bonds. 12. The higher the temperature at which the strand splits = the more closely related. 13. Lower the temp at which it splits = more distantly related.

Suggest one new source of info that has contributed to changes in classificatio

1. DNA hybridisation 2. Fossils 3. Immunology 4. DNA + AMINO ACID BASE SEQUENCES

What is this type of variation?

1. Discrete 2. Only two discrete classes

Taxnomy = The science behind classifcation

1. Each group within a natural biological classification = a taxon. 2. Taxonomy is the study of these groups and their position in hierarchical order = taxonomic marks. 3. Based upon the evolutionary line of descent. 4. Order: - Kingdom - Phylum - Class - Order - Family - Genus - Species

Disadvantage of using cytochrome C to construct a phylogenetic tree?

1. Extinct species not considered 2. No timing of events available 3. Only limited number of aa sequences 4. ONLY EUKARYOTIC CELLS, CAN'T INCLUDE PROKARYOTIC SPECIES.

Describe two other pieces of evidence scientists could use to classify cheetahs and leopards as being in diff genera.

1. Fossil record 2. Evolutionary history 3. DNA BASE/AMINO ACID SEQUENCE

Other than DNA base sequences, give two types of evidence that can be used to determine evolutionary relationships

1. Fossils 2. Courtship behaviour 3. Anatomy

Hierarchy

1. Groups within groups 2. No overlap between groups 3. Big groups are divided into smaller and smaller groups

Describe the principles scientists use to classify organisms into taxonomic groups

1. Hierarchical - groups within groups, no overalp 2. Based on similarities of characteristics 3. Evolutionary relationships, common ancestry, phylogenetic

Explain why these temperatures could be used to find the percentage of DNA hybridisation.

1. Higher temperature / more energy (required) the higher the percentage DNA hybridisation /more bases are similar/complementary / more base pairings; 2. Correct reference to breaking hydrogen bonds / more/less hydrogen bonds being present;

What does the phylogenetic tree show about the evolutionary relationship between fungi and insects

1. Insects + fungi have a common ancestor 2. They diverged a long time ago = BEFORE OTHERS, AT START OF TREE.

Comparing base sequences provides more evolutionary info than comparing STRUCTURE of proteins

1. Introns/non coding DNA 2. Degeneracy of code = more than one code for ea amino acid. 3. More bases than amino acids

Explain change in beak sizes

1. Lack of food for birds with smaller beaks 2. Only birds with large beaks survive 3. These breed + pass on alleles for larger beaks 4. INCREASED FREQUENCY OF ALLELES FOR LARGER BEAKS

Biologists can also use protein structure to investigate the relationship between different species of crane. Explain why

1. More closely related (species) have more similarities in amino acid sequence/primary structure; 2. In same protein / named protein e.g. albumin; 3. Amino acid sequence is related to (DNA) base/triplet sequence;

They found that hybrid DNA from a leopard and a cheetah separated into single strands at a higher temperature than hybrid DNA from a leopard and a puma. These results suggest that leopards are more closely related to cheetahs than to pumas. Explain why.

1. More hydrogen bonds form 2. More complementary bases 3. More similar DNA sequences

Male grouse vary in how aggressive they are, suggest two possible causes of variation in this aggressive behaviour.

1. Mutation produces new alleles for aggression 2. Independent seg/crossing over/random fertilisation = new alleles combos for increased aggression. 3. increased population density of males/ =decreased food supply/fewer females; = causes increased aggression to secure resources

Suggest an explanation for this relationship

1. Natural selection 2. In their habitat they are better camouflaged 3. Less predatation 4. In these habitats higher proportion survive 5. To pass on their alleles

Explain how these results suggest that animal A is the most closely related to humans

1. Only one amino acid different 2. Similar amino acid sequences 3. So similar DNA/base sequence

Binomial system

1. Organisms are identified by two names. 2. First name = generic name, denotes genus. 3. Second name = specific name, denotes species. 4. First name is capitalistic, second one isn't. 5. If specific name is not known, it can be written sp.

How does a phylogenetic system differ from a simple hierarchy

1. Phylogenetic based on evolutionary history 2. Shows ancestry of groups 3. Shows point of divergence (like reptiles and birds separated after reptiles and mammals). 4. Hierarchical based on SHARED CHARACTERISTICS, seen today

Suggest how the variety of colour patterns helps to maintain fish as different species

1. Selection of mate is dependent on colour pattern, species specific. 2. Prevents interbreeding, keeps gene pools separate

Immunological comparison of proteins

1. Serum from species A is injected into species B 2. Species B produces antibodies specific to all the antigen sites on species A 3. Serum is extracted from species B, this serum contains antibodies specific to antigens in the serum of A 4. Serum is extracted from species C (the animal you want to find out how closely related Species A is with). 5. Species B + C serum is mixed. 6. The antibodies respond to their corresponding antigens in the serum of species C. 7. The response is the formation of a precipitate. 8. Greater the number of similar antigens, the more precipitate is formed, the more closely related the species are. 9. The fewer the number of similar antigens, less precipitate formed and more distantly the species are related.

Species

1. Similar to one another but different from members of other species. 2. Capable of breeding to produce living, fertile offspring

Natural classification, what is it based upon. = Classification is the act of arranging organisms into groups based on their similarities and differences.

1. Similarity of characteristics 2. Evolutionary relationships between organisms 3. Arranges groups into a hierarchy

During courtship, wing vibration creates a sound. = sound is diff between two species of fruitfly = how doe this prevent mating between diff species?

1. Sound (acts as) sign stimulus 2. Fruit fly responds only to species-specific sound;

What do the results suggest about the evolutionary relationships?

1. State most closely related 2. State least closely related

Phylogeny

1. The evolutionary relationship between organisms is known as phylogeny. 2. Phylogenetics: the study of the evolutionary history of groups of organisms. 3. Tells us who's related to whom and how closely related they are. 4. Phylogenetic group: grouped according to evolutionary links/history/relationships/common ancestry. 5. All organisms have evolved from shared common ancestors. 6. Represented by a phylogenetic tree. 7. Closely related species diverged away from each other most recently. 8. Diverged longer ago, more distantly related. 9. Shows the fact that species have evolved over time. 10. Whether or not animals are extinct. 11. Closely linked to classification: members of one genus must be more closely related to each other than they are to organisms of a different genus.

Suggest how info on amino acid sequences is used to construct a phylogenetic tree

1. Those with similar sequences put in the same groups/more closely related 2. Greater difference in amino acid sequence, the longer ago the groups diverged

All organisms

1. have cytochrome C 2. (Cytochrome c structure) is more conserved / less varied (between organisms);

Comparison of base sequences = How could base sequences provide evidence that 2 animals are different.

1.We expect species that are more closely related to show more similarity in their DNA base sequences than those who are distantly related. 2. Different species would have different amino acid sequences. 3. Amino acid sequence is the result of the base sequence. 4. More closely related species have more similarities in amino acid sequences/primary structure. 5. Closer the amino acid sequence, closer the relationship.

Courtship, remember

Birds don't mate/pair bond with/recognise other species

Explain how comparing parent + baby beak lengths provides evidence for the role of genetic factors

Correlation between beak sizes in parents and offspring

If it states different species

DON'T TALK ABOUT CLOSE RP = Different species would have different amino acid sequences = Amino acid sequence is the result of DNA/alleles//base sequence

What is a species

Group of organisms with similar features/genes that reproduce to produce fertile offspring

Describe one way scientists could find out whether two diff populations belong to the same species

Interbreed If fertile offspring produced, same species

Explain what is meant by a phylogenetic relationship

Shows evolutionary relationship;

Why would they replace snakes in each courtship trial?

To avoid change in (courtship) behaviour (due to past experience);