Species, courtship, classification, and biodiversity Flashcards
What is a species?
can interbreed to produce fertile offspring, and will be similar to each other while being different to other species
When can hybrid offspring be produced?
when different species (rarely!) can interbreed to produce hybrid offspring, but these are infertile- such as a mule, from a horse and a donkey
Why are hybrid offspring infertile?
they have an odd diploid number
What is courtship?
animal activity that results in mating and reproduction. it may involve chemical, visual, or auditory stimuli
Why is courtship important?
-enables animals to recognise own species
-allows animals to approach each other without triggering aggression
-enables choice of a strong and healthy mate that is capable and ready for breeding
What is a sign stimulus?
something that indicates that an animal is ready to mate
What is the classification system we use?
the phylogenetic system
What is phylogeny?
the study of how closely related organisms are in terms of evolution
Why is the phylogenetic system described as a hierarchy?
-it has groups contained within larger groups
-with NO OVERLAP between groups
What are organisms grouped according to?
-common features
-common ancestors
Why do we need a system?
to understand relationships between organisms and to keep track of changes
What are some evidences for classification?
evolutionary history, similar features, biochemical differences, number and form of chromosomes, fossil records
What is the order of the taxa?
(Domain)
Kingdom
Phylum
Class
Order
Family
Genus/genera
Species
How do you know the scientific/binomial name of an organism?
the Genus species
-should be italicised/underlined and the genus should always have a capital letter
If organisms are part of the same order, what other taxonomic groups are they also all part of?
anything ABOVE order- domain/kingdom/phylum/class
What is a phylogenetic group?
a group that has common ancestors and common features
Explain genome sequencing to classify evolutionary relationships
-you can determine entire base sequences of an organisms DNA, which you can then compare to the DNA base sequence of another organism to see how closely related they are
-closely related organisms will have a higher % of similarity in their DNA base sequence
Explain comparing amino acid sequences in classifying evolutionary relationships
-proteins are made from amino acids
-the sequence of amino acids in a protein is coded for by the base sequence in DNA
-therefore more closely related organisms have similar DNA sequences so more similar amino acid sequences in their proteins
How can you test for DNA similarity?
by combining one DNA strand from each species-
-heat to break the hydrogen bonds between bases and separate strands
-mixing and cooling of the strands will let new hydrogen bonds reform between complimentary bases
-non-complimentary bases will not be able to join
-then you can measure the temperature required to separate the strands again
-this is because in hybrid strands where the two species are closely related, they have a more similar base sequence, so there are more bases that are complementary and form hydrogen bonds
-hence a higher temperature is needed to separate the two strands again
-hybrid strands where the two species are not closely related, they have fewer bases that are complementary so less hydrogen bonds so require lower temperatures to separate the two strands again
Explain immunological comparisons in classifying evolutionary relationships
-similar proteins will bind the same antibodies, just one is less efficient if they don’t fit quite as well
-proteins that bind antibodies will often form a precipitate in solution, so the more antibodies a protein binds, the more precipitate will form, so the density of the precipitate can be used to determine how similar the two proteins are, so how similar their base sequence DNA and ultimately how closely related the two species are
