Topic 4 Flashcards
What does biodiversity mean?
Biodiversity is the variety of living organisms in an area which takes into account species diversity and genetic diversity.
Species diversity is the amount of different species in one area
Genetic diversity is the variation of alleles in a species
What does endemism mean?
Endemism describes a species that lives exclusively in one area and cannot be found anywhere else
How has human activity decreased biodiversity?
As humans have expanded into different areas of wildlife we have taken resources like:
- Space
- Food
- Air quality
This then results in the extinction rate accelerating because of human activity
How do you measure genetic diversity?
To measure genetic diversity you can use heterozygosity index where a higher proportion of heterozygotes means greater genetic diversity
How would you use the heterozygosity index?
What is a niche?
An ecological niche is the way an organism exploits its environment and the role it has in its community.
If two organisms fill two different niches then they aren’t in competition with each other
What is co adaptation?
Like the orchid bee and the brazil nut the plant and the insects evolve and adapt in tandem with each other. Where the two becomes more adapted and depended on each other
What types of adaptations are there?
- Behavioural
- Physiological
- Anatomical adaptations
What are behavioural adaptations
Actions by an organism that help it survive and reproduce in response to their environment
- Sunflowers will turn their leaves towards he sun for better photosynthesis.
- Possums will play dead if they are threatened by a predator
What are physiolgical adaptations
Processes inside an organism that help them survive and reproduce
- Brown bears hibernate which lowers metabolism and conserves energy
- Some bacteria produce antibodies to kill other species of bacteria in the area
What are anatomical adaptations?
The external structural features of an organisms body increasing their chance of survival
- Otters streamline shape making it easier to glide through water allowing them to catch prey and escape predators
- Whales have a thick layer of blubber helping maintain optimal body temps
What does the term evolution mean?
Evolution is the change in allele frequency in a population over time and generations.
What is the process of natural selection?
What is allele frequency?
- Allele Frequency is the number of organisms in a species that possess a specific allele.
- Over time as a species evolves and new alleles are introduced through genetic mutations Allele Frequency will change
- The frequency is always less than 1
What is the Hardy Weinberg equation based off?
The Hardy-Weinberg equation Is based off the principle
Allele frequency will not change from one generation to the next
(This is only true when you assume that the population is has:
- A large population
- No immigration
- Random Mating
- No mutations
- No natural selection
Along with random mating so that all the genotypes are mixed with each other)
The Hardy-Weinberg equations are used to estimate frequency of alleles, genotypes, and phenotypes
What is the equation for predicting genotype and phenotype frequency?
Equation for frequency of one genotype if you know the frequency of the other genotypes
$p2 + 2pq + q2 = 1$
p2 = the frequency of the homozygous dominant genotype
2pq = frequency of the heterozygous genotype
q2 = the frequency of homozygous recessive genotype
What is reproductive isolation?
Reproductive isolation - a collection of mechanisms, behaviors, and physiological processes that prevent two different species reproducing with each other
How can reproductive isolation lead to different genetic variation?
- Geographical isolation (floods , volcanic eruptions, etc) will split isolate two groups of the same species
- If the conditions within the two groups like different climates
- These environments would mean different alleles would be prominent due to natural selection
- Eventually the two groups would become genetically distinct over time to the point where the two new variations would not be able to produce fertile offspring
How can these different genetic variations lead to new species
Changes in alleles can prevent individuals from breeding successfully because of:
- Seasonal changes – different flowering times or mating seasons
- Changes in shape of genitalia
- Changes in behaviour – different courtship rituals
What does the term classification mean?
Classification is the way you organise organisms into specific groups based on relationships between phenotypes and genotypes.
What is the incentive to classify?
By classifying organisms into groups we can see evolutionary relationships to:
- Find new sources for chemicals
- To use in commercial use like medicines
- Like finding less toxic chemicals form a chestnut tree from a sister species
What are the basic taxonomic groups?
What is molecular phylogeny?
Where organisms genetics are compared to where through DNA and gene sequencing you can compare alleles between different species and make evolutionary relationships between them. Where they are put into groups depending on how similar they are from one another.
What are the new domains and how did they come about?
Carl Woes
- Proposed the three domains (Archaea, Bacteria and Eukaryota)
- Based theory off molecular phylogeny
- Created to solve that some bacteria didn’t fit the bacteria class from RNA sequencing
How is proposals like Carl Woes’ evaluated?
New scientific information is evaluated through
- Conferences
- Journals
- Conducting the same experiments to validify the results and conclusions made.
- Using scientists own knowledge to compare thinking
What does ultrastructure mean?
Cell ultrastructure is all the organelles in cell
What is the ultrastructure of a plant cell?
What is the cell wall and its functions?
- Made of cellulose
- Rigid structure surrounding cell
- Supports structure
- Prevents uptake of water
What is the plasmodesmata and its functions?
Plasmodesmata
- cytoplasmic canal
- Cell wall channels linking adjacent cells
- Communication and transport between cells
What is the pits and its functions?
- Where the cell wall is very thin
- Arranged in pairs
- Transport of substances
What is the chloroplast and its functions?
- Small flattened structure
- Double membrane
- Inside is smaller thylakoid membranes
- Stacked in some parts ← grana
- Grana linked by lamellae (thin pieces of thylakoid)
- Photosynthesis takes place
- Photosynthesis also in stomata
What is the amyloplast and its functions?
- Small membrane bound organelle
- Stores starch granules
- Stores starch grains and converts starch to glucose
What is the vacuole and the tonoplast and thier functions?
- Membrane (tonoplast) bound compartment
- Tonoplast controls substance movement of vacuole
- Has cell sap
- Keeps cell turgid
- Involved in breakdown and isolation of excess chemicals
- Storage for organic compounds like proteins in seed cells
What does a plant cell look like under a electron microscope?
What is the structure of amylose?
- Unbranched chain of alpha glucose
- 1,4 glycosidic bonds
- Compact coiled structure
What is the structure of amlopectin?
- Long branched chain of alpha glucose
- Lots of side branches for easier breakdown → release of energy
What is the structure of cellulose?
- A polysaccharide of beta-glucose
- straight 1,4 glycosidic bonds making the chains straight
- 50 - 80 chains + hydrogen bonds = Microfibrils
How is cellulose used in cells walls?
- In the primary cell wall cellulose is in a linear structure where microfibrils are parallel to each other for better strength
- In the secondary cell wall microfibrils are in a net / matrix with the addition of lignin and where the cell wall can grow for even stronger plant fibers (secondary thickening)
What are xylem vessels and their use?
- Water and mineral ions move in and out of the vessels through pits where there is no lignin
- Long, tube like structures from dead cells found together in bundles
- Walls thickened with lignin to provide extra support
- Hollow limen with no end walls and no cytoplasm (Uninterrupted tube)
- Water would diffuse out through the stomata (transpiration)
- Cohesion and adhesion allows for a transpiration steam (cohesion tension theory)
What are phloem tissue and their function?
- Transports ORGANIC SOLUTES mostly sugars from production location to where they are needed (Translocation)
- Cells arranged in tubes
- Purely transport tissue
- contains cells with sieve tube elements and companion cells
- Sieve parts are end walls which has holes to allow for solutes to pass
- Sieve tube elements have:
- no nucleus
- thin cytoplasm
- few organelles
- Companion cell aids survival or Sieve tube
- Provides living functions for both itself and sieve tube like active transport to move the solutes up the tube
- Where pumping increases pressure to where sucrose can move around the cell
Where are xylem vessels, phloem tissue found?
Xylem vessels and phloem tissue form vascular bundles which are grouped together in vascular bundles
What is the method for bacterial growth practical?
