3.4- Chapter 10- Biodiversity

Question 1

Why is classification important?

Answer 1

Vast array of species- some undiscovered and some extinct- need to be named and classified- organised into groups. First need to be differentiated.

Question 2

What is a species?

Answer 2

• Organisms capable of breeding to produce fertile offspring- any of their genes can be combined in reproduction.
• Can be identified through variety of methods including courtship behaviour.

Question 3

How are species named?

Answer 3

• The binomial system which is a universal (standardised to avoid confusion) nomenclature (naming system) using Latin or Greek.
• First name- the genus name and starts with the capital letter like a surname. Shows closest relatives.
• Second name- lower case and species name- specific just like first name.
• Names are written in italics or underlined if handwritten.
• If the species is unknown sp. is written.

Question 4

Why are names of organisms not perminant?

Answer 4

• Names of organisms is in a constant state of change.
• Classification of organisms also changes with new evidence.

Question 5

How does courtship behaviour help to distinguish between species?

Answer 5

• Behaviour- helps to distinguish species as well as physical and biochemical resemblance.
• Species recognise each other based on behaviour and these are genetically determined and evolved- courtship and mates are essential for species survival.
• Species specific- only members of the same species for reproductive success- used to classify species- more closely related= more similar courtship behaviour.

Question 6

Why is reproduction important?

Answer 6

Ensures species survive over time- species adapted to ensure DNA passed on through preproduction e.g. females only produce eggs at certain times- important to ensure successful mating and that offspring have maximum chance of survival.

Question 7

Why is courtship behaviour important?

Answer 7

• Recognise members of the same species to produce fertile offspring.
• Identify mates capable of breeding- fertile and sexually mature.
• Pair bond- successful mating and raising of offspring.
• Synchronise mating- sperm and egg have most chance of meeting each other.
• Become able to breed- enter physiological state to allow breeding.
• Females- only fertile and receptive to mating when produce eggs- courtship behaviour allows males to see if females are fertile- response- offspring, not fertile- different response- male goes away.
• Species specific- only members of the same species for reproductive success-
• May also be done between same sexes in competition.

Question 8

How do animals perform courtship behaviour?

Answer 8

• Use signals in courtship behaviour- chain of actions- same for fertile members of the same species but different otherwise- enables recognition of the same species who is fertile.
• Simple behaviours- releasing hormones/ chemicals- pheromones, sound- roaring,, visual displays- feathers.
• Complex behaviours- dancing, building nests.

Question 9

What is classification?

Answer 9

Grouping species together into manageable groups- allows better communication.

Question 10

What is taxonomy?

Answer 10

Taxonomy- science of classification- naming and organising organisms to make them easier to identify. Study of groups and positions in hierarchy- taxonomic ranks.

Question 11

What is phylogeny?

Answer 11

Study of evolution of organisms.

Question 12

What are the different types of classification?

Answer 12

• Artificial classification- based on physical characteristics but may be analogous- same function but different evolutionary origin e.g. butterfly vs. birdwings- flawed.
• Phylogenetic classifications- based on evolutionary relationships between organisms.

Question 13

Describe the features of phylogenetic classification.

Answer 13

• Based on evolutionary relationships between organisms.
• Classified using shared features with ancestors arranged in hierarchy- groups in larger groups but no overlap.
• Tells which species are related and how closely.
• Based on homologous characteristics- similar evolutionary origin hierarchies or function e.g. bird wings, human arms and horse legs have the same evolutionary origin and basic structure- homologous.

Question 14

What are taxonomic ranks and what is their hierarchy based on?

Answer 14

• Taxonomic ranks- position in phylogenetic hierarchy
• Taxonomic ranks hierarchy- based on phylogeny- evolutionary line of decent.

Question 15

Describe phylogenetic (evolutionary trees).

Answer 15

• All organisms- shared common ancestors shown by phylogenetic- evolutionary- trees:
• Reflective of evolutionary branches species derived from- oldest species at the bottom and recent ones at the end.
• Closely related species diverge most recently and their branches are closer
• The first branch represents the common ancestor of all the species in the diagram- it may be extinct along with other older species.
• Divergences are represented by branches from common ancestors.