Unit 4: Biodiversity Flashcards
What is biodiversity?
Biodiversity is the variety of living organisms in an area. Includes:
- Species diversity: the number of different species and the abundance of each species in an area. (E.g. wood contains many different species like plants, insects, birds, and mammals)
- Genetic diversity: the variation of alleles within a species (or a population of a species like human blood types determined by a gene with three different alleles)
A population is a group of organisms of the same species living in a particular area.
What is endemism?
It is when species is unique to a single place and it isn’t usually found anywhere else in the world. E.g. the giant tortoise is endemic to the Galapagos Islands and can only be found there.
What is natural selection?
Adaptation and evolution has increased biodiversity, but human activities are reducing species diversity- causing biodiversity to fall.
What is conservation?
Help maintain biodiversity. Important for endemic species because they are particularly vulnerable to extinction as they can’t migrate number will decline.
How can species diversity be measured?
Count the number of different species within the area- species richness. Higher the number of species, the greater the species richness but gives no indication of the abundance of each species.
Count the number of different species and the individuals within a species (they have different alleles) - index of diversity.
To do this use a random sample
What is genetic diversity?
It is the variety of alleles in the gene pool of a species. Gene pool is the complete set of alleles in a species. Greater the variety of alleles, the greater the genetic diversity. You can look over time or look at two populations of the same species show different diversity.
What is the phenotype?
Observable characteristic. Different alleles code for slightly different versions of the same characteristics. Looking at different phenotypes in a population of a species, you can get an idea of the diversity of alleles. Large number of different phenotypes= greater genetic diversity
What is the genotype?
Sequence of the base pairs analysed, Order of bases in DNA is slightly different. You can look at similarities and differences. Measure the number of different alleles to see how genetically diverse. The larger the number of different alleles, the greater the genetic index.
Heterozygosity index:
H= number of heterozygotes/ number of individuals in the population
How to calculate the index of diversity?
It takes into account both the number of species and the abundance.
D=N(N-1)/ Sum of n(n-1)
N= total number of organisms of all species
n= total number of organisms of one species
Higher the number the more diverse it is. Compare species diversity in different habitats.
What is the niche?
Role organism plays in the community. Interactions between living and non-living organisms. Unique niche- can only be occupied by one species. There can be slight differences. If two species try to occupy the same niche, they will compete, the more successful one will be left.
How can an animal adapt?
Behavioural- ‘play dead’ or dance before mating like scorpions.
Physiological- Brown bears hibernate
Anatomical (structural)- Otter have a streamlined shape.
How do adaptations become more common with evolution?
Mutations introduce new alleles- variation in their phenotypes. Determine characteristics that can make an individual more likely to survive.
Selection pressures such as predation, disease, competition- struggle for survival. Individual without advantageous alleles don’t survive- fewer individuals- less competition for resources. Individuals who are adapted more likely to survive- reproduce and pass on to offspring. Over time the number of individuals with advantageous alleles increase. Evolution- favourable adaptations become more common. Charles Darwin. Example: Peppered moths
What is speciation?
Species is a group is similar organisms that can reproduce to giver fertile offspring. Speciation is the development of a new species. Occurs when the same species become reproductively isolated (due to geographical isolation or a random mutation) - changes in the alleles and phenotypes of the population prevent them from successfully breeding together. Changes include:
- Seasonal change- mating season
- Mechanical changes- changes in the genitalia
- Behavioural changes- courtship rituals
How can geographical isolation lead to speciation?
Physical barrier divides population- volcanic eruption, floods, earthquakes. Conditions will be different- different climates. This causes different characteristics to become more common due to natural selection- different selection pressures.
Characteristics will be advantageous on each side, allele frequency will change, increase on one side. Mutations will take place independently, changing allele frequency. lead to changes in phenotypes frequencies. They will become genetically distinct- won’t be able to produce fertile young- reproductively isolated
Why is the Hardy-Weinberg equation used?
Used to estimate the frequency of particular alleles, genotypes and phenotypes within a population.
What is the Hardy-Weinberg equation to predict the allele frequency?
p + q = 1
p= frequency of dominant allele
q= frequency of recessive allele
What is the Hardy-Weinberg equation to predict the phenotype and genotype frequency?
p^2 + 2pq + q^2 = 1
p^2= frequency of homozygous dominant genotype
2pq= frequency of heterozygous genotype
q^2= frequency of homozygous recessive genotype
What does classification do?
Taxonomy is the science behind classification. Organising them into groups between their similarities and differences. It goes Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species. Different species can’t produce fertile young. Same species- very similar. Based on their phenotype, genotype and how related they are.
What are the 5 kingdoms?
Prokaryotae (bacteria), Protoctista (algae), Fungi (moulds), Plantae (mosses), Animalia (fish)
What can new data do to classification?
Influence the way it is classified. It can lead to an organism being reclassified or lead to changes in the classification system structure. Tentative nature
How to zoos and seedbanks help to conserve endanger species?
Extinction of a species or loss of genetic diversity causes a reduction in global biodiversity. Endangered species - risk of extinction because of low population or a threatened habitat. Conservation involves the protection and management of endangered species. Zoos and seed banks help to conserve endangered species and genetic diversity.
What is a seedbank?
Stores seeds from lots of different species of plants- endangered. Used to grow new plants. Conserve genetic diversity. Range of seeds from plants with different characteristics- different alleles.
Involves:
- Cool, dry conditions- long time
- Testing seeds for viability (ability to grow plant)- planted, grown, new seeds are harvested
Pros:
- Cheaper, Large number, Less labour, stored anywhere, less likely to be damaged by disease
Cons:
- Testing for viability is expensive and time- consuming and for all plants to be tested, difficulty to collect seeds from remote locations
What is a zoo?
Captive breeding programmes. Controlled environment. Endangered species or extinct in the wild- bred together - increase numbers. However, problems breeding outside their natural habitats, hard to recreate, people may think it is cruel.
