Unit 4 Flashcards
What is a niche?
the role of an organism within it’s community. A niche has boundaries and it’s role includes:
- what it eats
- what eats it
What is an ecological niche?
When both organisms share the same habitat and same food but hunt at different times, meaning they both survive
Name the 3 things there is competition for:
- Territory
- Mates
- Resources
True or false: 2 species can occupy the same niche, habitat and resources?
No 2 species can occupy the same niche in the same habitat at the same time for the same resource
What is a species?
A group of organisms with similar morphology, physiology and behaviour which can interbreed to produce fertile offspring
What is a habitat?
the place where organisms live
What is a population?
a group of interbreeding individuals
What is a community?
all the organisms living in a habitat
Describe what a behavioural adaptation is and give an example:
A behavioural adaptation is an action by an organism which helps it survive or reproduce; an example is nocturnal animals
Describe what a physiological adaptation is and give an example:
A physiological adaptation is a feature of the internal working of organisms that help them to survive and reproduce; an example is scurvy grass
Describe what a anatomical adaptation is and give an example:
An anatomical adaptation is an adaptation we see when we observe or dissect organisms; an example is the pollen basket on the hind legs of bees
Explain evolution by natural selection
Organisms with better are adaptions will create a population with ideal characteristics as they’re more likely to survive, more likely to reproduce and more likely to pass on their advantageous alleles
What is evolution?
a change in allele frequency in a population over time
Is an organism more or less likely to survive if they’ve got non-advantageous alleles?
They’re less likely to survive
What is a gene pool?
The complete range of alleles in a population
When is the Hardy Weinburg equation valid?
When random mating occurs
What is the Hardy Weinburg equation?
P^2 + 2pq + q^2
What do the letters stand for in the Hardy Weinburg equation?
P^2 = homozygous dominant 2pq = heterozygous / carrier q^2 = homozygous recessive
The ability of a population to adapt to new conditions will depend on what things?
- the reproductive rate of an organism
- The strength of the selection pressure
- the size of the gene pool
What has to happen for a new species to arise?
reproductive isolation
What is the most effective method of reproductive isolation?
A geographical feature such as high mountains as it prevents a group of individuals from breeding with the rest of the population.
What is speciation?
When two groups of organisms become less like each other due to selection pressures. They eventually may not be able to interbreed
What is biodiversity?
The richness and variety of life
What is taxonomy?
The science of classification
Why is classification of systems being constantly updated ?
More species are being created by mutations causing speciation
What is the binomial naming system ?
A system that names species. It takes the genus and species e.g homo sapien
What is phylogenetics?
The study of the evolutionary history of groups of organisms
Who was Carl Woese?
- was a scientist in 1960s to 1970s
- he worked on evolutionary relationships in prokaryotes
- he found an anomaly in methanogens
List everything in the taxonomy hierarchy
- Domain
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
What are the 3 domains?
Bacteria, Archae and Eukaryota
What is convergent evolution?
Where 2 organisms who are unrelated evolve similar adaptations due to selection pressure
What is the diversity index equation ?
D=N(N-1) / Sigma n(n-1)
N=total number of organisms of all species
n=total number of organisms for each species
Describe an endemic
A disease or condition found in a certain, small area
Describe a pandemic
A disease or condition found in many regions or a large area
What is genetic diversity ?
The total number of genetic characteristics in the genetic makeup of a species
Describe species richness
The number of a species present in a given habitat
Describe a genetic drift
The change in the allele frequencies over time and leads to reduction in genetic variation
Explain inbreeding depression
In a small population there is a higher chance of inbreeding which causes recessive alleles. These alleles are harmful and can cause inbreeding depression
Why are studbooks used?
They’re used to avoid inbreeding depression and loss of genetic variation by genetic drift
What is a seed bank?
A seed bank stores seeds to preserve genetic diversity
How should seeds be kept to ensure they stay usable?
- dried
- low humidity
- stored at -20 degrees so plant growth is lowered due to metabolic rates as enzyme activity is lowered
How often should seeds in a seed bank be tested?
They should be tested every 10 years for viability
What are the aims of a captive breeding programme?
- Increase the number of individuals of the species if numbers are low
- Maintaining genetic diversity
- Reintroducing animals into the wild
True or false: Cellulose in a monosaccharide
False: Cellulose is a polysaccharide
What monomer makes up cellulose?
Beta glucose
What type of bonds are found in cellulose?
1-4 glycosidic
How many glucose units are found in a cellulose chain?
1000 to 10,000 units
Describe the formation of microfibrils
Hydrogen bonds form between the -OH groups in neighbouring cellulose chains
What is the ‘glue’ that holds together microfibrils?
Pectin and hemicellulose
True or false: hemicellulose and pectin are long, branched polysaccharides?
False: they are short, branched polysaccharides
Where is pectin founds and what does it do?
It is found in the middle lamella and holds together the cell walls of adjacent cells
What is in the vascular bundle?
- Xylem
- Phloem
- Sclerenchyma
- Parenchyma
- Collenchyma
Explain how the structure of the xylem is useful for its function
- Lignified= strong and waterproofed
- Dead, hollow tubes=allow water to be drawn up by the transpiration stream
Explain how the structure of the phloem is useful for its function
- Sieve plates=strengthen and maintain shape
- Long columns=enable rapid transpiration
Describe transpiration
- Water vapour diffuses out through the stoma down a diffusion gradient
- Water evaporates from the surface of cells
- Water replaced by capillary action in cell walls
- Water is drawn out the xylem
- A continuous column of water is drawn up through the xylem
