Key concepts Flashcards
Define endemism
A species which only exists in a certain geographical area.
Define Species diversity
The number of different species and the abundance of each species in an area
eg-a forest would contain many different species of plants,insects,birds,mammals
Define Genetic diversity
The variation of alleles within a species
-eg , human blood in humans is diverse=high genetic diversity within humans
How can we measure species diversity?3 steps
- count number of different species in an area (richness)
- count the number of individuals in each species(evenness)
- Use these values to calculate the index of diversity to calculate species diversity
What is the formula for index of diversity , what are the symbols representing and what does it measure ?
- D=N(N-1) / £n(n-1)
- N= total number of organism of all species , n=total number of organisms of each species individually, £ = sum of
- Measure species diversity
What conclusions can be drawn from calculating the Index of Diversity ?
You can compare the species diversity in different habitats by comparing which has a higher calculated answer
What conclusions can be drawn from calculating the Index of Diversity ?
You can compare the species diveristy in different habitats
Why is calculating species diversity unreliable ?2 points
- Only a sample of an area is taken so it is not representative of the whole habitat
- N and n are estimated
What measures are taken in calculating species diversity to make it as fair as possible ? 3 points
- A random sample is taken to prevent bias
- Repeating the process in the same habitat to get a more inclusive result
- Using the same sampling technique when sampling different habitats
Define the words phenotypes and genotype
Phenotype= observable characteristics of an organism
Genotype=the genetic constitution of an organism
What does a high number of different phenotypes and different alleles indicate?
a high genetic diversity
What is the heterozygosity index formula and what does it measure ?
The heterozygosity index measures genetic diversity
H= number of heterozygotes / number of individuals in a population
Define a niche
how a species exploits/uses its habitat
What happens when two species try occupy the same niche ?
They will compete with eachother , one species will be more successful than the other (dues to adaptation) until one one species is left
Describe and explain the three types of adaptations
Behavioural-They way an organism acts to increase its chances of survival -possums playing dead when to escape attack
Physiological- the internal processes in the organisms body to increase survival
Anatomical-Structural features to aid survival
How do scientists publish their discoveries
They come up with a theory and test it , tell other scientist who will aslo test out the theory ,If there is supported evidence it is accepted
Describe the process of evolution by natural selection
Mutations occur in a population that introduces new alleles , some of these alleles become favourable since they allow the organism to survive.
Selection pressures like disease, create a competition and a struggle for survival
Those who posses the advantageous allele will survive while those who don’t will not
This advantageous allele will be passed onto the offspring through reproduction
Overtime the frequency of the advantageous allele will increase
This leads to evolution over generations as they become more common
Define Evolution
The change in allele frequency
Define speciation
The development of a new species (through evolution)
Three aspects that lead to speciation
Mechanical changes= changes in genitalia that prevent mating
Seasonal changes=Organisms becoming sexually active at different time of the year
Behavioural changes=Chang in courtship rituals that are no longer attractive to the opposite sex
Define geographical isolation
When a physical barrier divides a population of species eg, volcanos , mountains, rivers
Explain how geographical isolation can lead to speciation
Conditions on either side will be different therefore different alleles will become common on each side, Eventually the different populations will become genetically distinct .
Would have changes so much they can no longer breed to produce fertile offspring
Become reproductively isolated,and become separate species
What is the Hardy weinberg formula and what does it predict and mean ?
It predicts allele frequency (population change over time)
It means that allele frequency wont change from one generation to the next (excludes evolution)
p+q=1
p2+2pq+q2=1
What is taxonomy ?
The science of classification
Name the five kingdoms
Animalia, Protoctista, Prokaryotae,Fungi,Plantae
Name the taxonomic groups going down
Domain, Kingdom, Phylum, Class ,Order, Family, Genus ,Species
Name the three domains
Bacteria, Archaea, Eukaryota
Define molecular Phylogeny
The analysis of different molecules to see how closely related organisms are
How can organisms be reclassified
Due to new technology , DNA sequence can be identified and can be significantly different to what it was mistakenly classified as , therefore it is reclassified into a new family
How does the scientific community evaluate data?
Findings are published in scientific journals and conferences
and is then further studied in peer reviews
What are amyloplasts
Organelles that contain amylopectin enclosed by a double membrane
What are tonoplasts
The single membrane around the vacuole to provide strength and structure
What is a plasmodesmata?
An extension of the cell cytoplasm between cell walls that transportation of substances
What are pits?
Thin sections in cell wall which allow communication between adjacent cells
Structure of chloroplasts
Stroma- fluid inside
Thylakoids that include chlorophyll
Grana= collection of thylakoids
Lamellae= connects the thylakoids
What is a middle lamellae
In cell walls , made of calcium pectate to hold adjacent cells together
