species and taxonomy

Question 1

define species

or

How do you know if animals are the same species

Answer 1

If two organisms belong to the same species they are able to produce fertile offspring

Offspring from 2 different species mating may be infertile because they will have an odd number of chromosomes so can’t perform meiosis to produce (haploid) sex cells

Question 2

Explain how courtship behaviour is a necessary precursor to successful mating and its role in species recognition.

Answer 2

-Allows recognition of members of the same species because courtship behaviour is species specific
-Production of fertile offspring
-Indication of sexual maturity
-Recognition/attraction of opposite sex
-Stimulate release of gametes
-Establishes a pair bond to raise young
-Synchronise mating → maximum probability that sperm
will fertilise ovum

Question 3

Taxonomy

Answer 3

arranging organisms into groups based on similarities and differences.

Question 4

Phylogenetic classification system

Answer 4

Arranges species into groups based on their
evolutionary origins (common ancestors) and relationships

Question 5

What is a hierarchy

Answer 5

Smaller groups placed within larger groups
No overlap between each group
Each group = taxon

Question 6

What are the problems with classification

Answer 6

Defining a species is difficult when, reproductive behaviour cannot be observed because

-The organisms are extinct
-Reproduce asexually

Question 7

List the 8 taxa in their hierarchical order starting with the
largest group:

hint use acronym learnt in class

Answer 7

Domain (do)

Kingdom (keep)

Phylum (pans)

Class (clean)

Order (or)

Family (family)

Genus (get)

Species (sick)

Question 8

What 2 taxa make up the binomial system?

Answer 8

genus and species

Question 9

What is the advantage of the binomial system?

Answer 9

universal; no confusion as many organisms have more than one common name

Question 10

Describe the principles on which the system of
classification of living organisms is based.

Answer 10

Hierarchy of 8 taxonomic groups
no overlap between groups;
organisms placed in groups due to common structures
reflecting evolutionary history (phylogeny) of organisms within a group;

Question 11

How do scientists clarify evolutionary relationships between organisms

Answer 11

Genome sequencing
Immunology

Question 11

Explain how genome sequencing helps to clarify evolutionary relationships between organisms

Answer 11

Compares the order of base sequence of the whole genome of different species

Higher % match = more closely related

Question 12

Explain how Immunology helps to clarify evolutionary
relationships between organisms

Answer 12

DNA → mRNA → sequence of amino acids in polypeptide
So tertiary structure of protein tells us about sequence of DNA
If same antibody binds to a specific antigen then it is closely related

Question 13

DNA hybridisation

Also a way to clarify evolutionary relationship

Answer 13

DNA from 2 species is collected, heated and separated into single strands
The 2 separates species DNA is mixed and allowed to cool, this allows H-bonds to
reform between complementary base pairs. The more similar the base sequences the
more H-bonds that will form.