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
What is biodiversity?
a measure of how varied an ecosystem is
What is species diversity?
a measure of how many different species are present in an area, and how many individuals of these species there are
What is a population?
a group of organisms of the same species living in a habitat
What is a community?
all the populations of all the species within a particular habitat
What is species richness?
the number of different types of species in a particular area. the greater the number of species, the richer the area
What is species evenness?
this is a comparison of the size of the population of different species in a particular area
Species diversity within an area increases as…
both species richness and species evenness increases
What is Simpson’s index of diversity, and what does each part stand for?
D = N(N-1) / Σ n(n-1)
N = add all the members of all species together
n = number of organisms in a particular species
find out N by adding all species numbers together
find out Σ n(n-1) by adding a new column, finding n(n-1) for each species, then add them all to place on the bottom of the formula
What is the lowest possible value of D and what does this mean?
lowest possible value of D is 1, and the larger the value of D the greater the diversity
What is conservation?
the study and protection of biodiversity and natural resources
What two measurements are needed to calculate biodiversity index?
number of individuals of each species, total number of species
Why is protecting biodiversity important?
-prevents extinction of species
-some species may be useful for medicine or agriculture
What is the difference between the two measures of biodiversity?
species richness only measures the number of different species, not the number of individuals in each one
Why is the index of diversity more useful in measuring biodiversity?
-also measures the number of individuals in a species
-this is important as some species may be present but only in very low numbers
How does deforestation affect biodiversity?
-decreases variety of plants
-decreases habitats
-decreases variety of food sources
so the biodiversity is decreased
How can we reduce the impact of deforestation?
sustainable logging/ carefully choosing which trees to cut down and replacing trees cut down
How does planting hedgerows affect biodiversity?
-increased variety of plants
-more habitats
-increased variety of food sources
so the biodiversity is increased
How does monoculture affect biodiversity?
-decreases biodiversity as only one species of crop is being grown
-less variety of habitats and food sources
-more susceptible to being wiped out entirely by disease
so the biodiversity is decreased
How does the use of pesticides affect biodiversity?
-excessive use of pesticides contaminate the surrounding soil and water sources which causes a loss in biodiversity
How can we combat the problems with monoculture?
yearly crop rotation
How can we combat the problems with pesticides?
use biopesticides, like ladybirds, as they are non-toxic and effective, safe and sustainable
State 4 biological advantages of farmers planting hedgerows
-increases biodiversity
-greater amounts and more varied food sources
-reduced need to pesticides
-provides more habitats
Why is monoculture beneficial to farmers?
less farming equipment needed
cheaper food
Why are pesticides beneficial to farmers?
raises productivity per hectare by keeping crops healthier and more protected
Describe how you would collect a random sample of….?
-use a computer to generate random coordinates
-place quadrat in that random location
-collect all of ….. in the quadrat
How could you estimate the number of …. in an area?
-split areas into squares using a grid
-use a computer to randomly generate coordinates
-place quadrats in this random location
-count the number of …. in the quadrat present
-figure out the mean per quadrat
Why is it important that data is collected from random samples?
to remove bias
Why is it important to use a large number of samples?
-to ensure the sample was representative
-to produce a more reliable mean
-allows you to see anomalous results more easily
Why does biodiversity increase?
more varieties of plants
so more habitats
so more varieties of food sources
Explain when you would use different types of stats tests
chi squared- categories
t- test- means
spearman rank- correlation
