Biodiversity Flashcards
What is a species?
They are capable of breeding to produce living, fertile offspring.
This means that, when a species reproduces sexually, any of the genes of its individuals can be combined with any other.
What was the system before the binominal naming system?
Scientists gave new organisms a name that described their features, e.g. blackbird, or rainbow trout.
This resulted in the same names being used in different parts of the world for very different species.
So it was difficult for scientists to be sure they were referring to the same organism.
What is the binominal naming system?
It is a universal system based upon Latin or Greek names.
The generic name denotes the genus to which the organism belongs.
The specific name denotes the species to which the organism belongs.
What are the rules of the binominal system?
The names are printed in italics or, if handwritten, they are underlined to indicate that they are scientific names.
The first letter of the generic name is in upper case, but the specific name is in lower case.
If the specific name is not known, it can be written as ‘sp.’ (in italics), for example Felix sp. (italics)
What is courtship behaviour?
Members of the same species are physically and biochemically similar and can therefore distinguish members of their own species.
The behaviour of members of the same species is more alike than that of members of different species.
Individuals can therefore recognise members of their own species by the way they act.
The ability to display a behaviour is genetically determined.
It too has evolved and it influences the chances of survival.
How does courtship behaviour help achieve successful mating for survival?
They enable individuals to:
Recognise members of their own species, to ensure mating only happens in a species, as outside offspring are infertile.
Identify a mate that is capable of breeding because both partners need to be sexually mature, fertile and receptive to mating.
Form a pair bond that will lead to successful mating and raising of offspring.
Synchronise mating so it takes place when there is maximum probability of sperm and egg meeting.
Become able to breed by bringing a member of the opposite sex into a physiological state that allows breeding to occur.
What happens during courtship - females?
The females undergo a cycle of sexual activity in which they can only conceive during a very short time.
They are often only receptive to mating for a period around the time when they produce eggs.
Courtship behaviour is used by males to determine whether the female is at this receptive stage.
If she responds with the appropriate behavioural response, courtship continues and is likely to result in the production of offspring.
If she is not receptive, she exhibits a different pattern of behaviour and the male ceases to court her, turning his attentions elsewhere.
What happens during courtship - chains?
During courtship, animals use the signals to communicate with a potential mate and with members of their own sex.
Typically there is a chain of actions between a male and a female.
The chain of actions is the same for all members of a species but differs for members of different species.
Both individuals will recognise that their partner is of the same species and that they may be prepared to mate.
What is classification and taxonomy?
Classification is organising species into more manageable groups, which allows better communication between scientists and avoids confusion.
Taxonomy is the theory and practice of biological classification.
What is artificial classification?
It divides organisms according to differences that are useful at the time.
Such features may include colour, size, number of legs, leaf shape etc.
These are described as analogous characteristics where they have the same function but not the same evolutionary origins.
For example, the wings of butterflies and birds are both used for flight but originated in different ways.
What is phylogenetic classification?
It is based upon the evolutionary relationships between organisms and their ancestors.
It classifies species into groups using shared features derived from their ancestors.
It arranges the groups into a hierarchy, in which the groups are contained within larger composite groups.
What are the relationships in a phylogenetic classification?
Relationships are partly based on homologous characteristics.
Homologous characteristics have similar evolutionary origins regardless of their functions in the adult of a species.
For example, the wing of a bird, the arm of a human and the front leg of a horse all have the same basic structure and evolutionary origins and are therefore homologous.
What is a taxon?
Each group within a phylogenetic biological classification.
Taxonomy is the study of these groups and their positions in a hierarchical order, taxonomic ranks.
These are based upon the evolutionary line of descent of the group members.
What is a domain?
The highest taxonomic rank and there are three recognised: Bacteria, Archaea (prokaryotes), and Eukarya.
What is bacteria?
A group of single-celled prokaryotes with these features:
The absence of membrane-bound organelles, nucleus and mitochondria.
Unicellular, though cells may occur in chains or clusters.
Ribosomes are smaller.
Cell walls are made of murein.
Single loop of naked DNA made up of nucleic acids, no histones.
What are archaea?
A group of single-celled prokaryotes that were originally bacteria as they resemble in appearance.
Different from bacteria because:
Genes and protein synthesis are more similar to eukaryotes.
Their membranes contain fatty acids attached to glycerol by esther linkages.
There is no murein in their cell walls.
Have a more complex form of RNA polymerase.
What are eukarya?
A group of organisms made up of one or more eukaryotic cells.
Their cells possess membrane-bound organelles.
They have membranes containing fatty acid chains attached to glycerol by ester linkages.
Not all possess a cell wall, but have no murein.
Ribosomes are larger.
What is the classification of Eukarya?
The Eukarya domain is divided into Protoctista, fungi, plantae and animalia.
Within each kingdom the largest groups are known as phyla.
Organisms in each phylum have a body plan radically different from organisms in any other.
Diversity within each phylum allows it to be divided into classes.
Each class is divided into orders of organisms that have additional features in common.
Each order is divided into families and at this level the differences are less obvious.
Each family is divided into genera and each genus into species.
What is phylogeny?
The evolutionary relationship between organisms is known as phylogeny.
The phylogenetic relationships of different species are usually represented by a tree-like diagram called a phylogenetic tree.
The oldest species is at the base of the tree while the most recent ones are represented by the ends of the branches.
