Topic 4 - Biodiversity + natural resources Flashcards
Species
a group of organisms with similar morphology, physiology and behaviour, which can be interbred to produce fertile offspring.
Binomial classification
Two part Latin name given to species:
first part: genus
second part: species
hybrid
animals made by breeding two animals together of the same genus but not species
habitat
the place where an organism lives
each habitat has a particular set of conditions that supports a distinctive combo of organisms
population
interbreeding group of the same species found in an area
community
various populations in a habitat
Niche
the way an organism interacts with/exploits its environment
Adaptation
features that enable organisms to survive.
adaptations can be classed as behavioural, physiological or anatomical
behavioural adaptations
actions carried out by the organism helping it survive/reproduce
physiological adaptations
the features of the internal workings of an organism that helps it survive/reproduce
anatomical adaptations
structures we can see when we observe/dissect an organism
co-adaptation
when plants and insects evolve in tandem and become dependent on each other and more closely adapted
stages of natural selection
- Variation within species (mutations)
- Change in environment (selection pressure creates competition)
- Survival of the fittest (those best adapted survive)
- Better adapted reproduce and pass on alleles to offspring, the allele that is favourable will become more common
Natural selection results in organisms well adapted to particular niche.
evolution
the change in in allele frequency of a population over time (generations)
selection pressure
change in the environment give some organisms an advantage and others a disadvantage
gene pool
all the alleles of all the genes in a population
variation must exist in a gene pool for evolution to occur
mutation
Changes in DNA sequence
they are likely to accumulate in gene pools of large populations, each mutation creates a new allele
advantageous change
individual is more likely to survive and reproduce - allele frequency in population will increase
disadvantageous change
natural selection will remove it from the gene pool
neutral change
no change in chances of survival, remains in the gene pool by change
genotype
genes you inherit, all the genes an organism has
phenotype
affected by genotype and the environment, the physical characteristics observed
the alleles of a population will remain constant if..
- There are no mutations so no new alleles are created
- There is no immigration/emigration so no alleles are introduced/lost
- There is no selection, no alleles are favoured/eliminated
- Mating is random so alleles are randomly mixed
- The population is larger so there are no genetic bottlenecks
ability of a population to adapt depends on…
- Strength of selection pressure
- Size of gene pool
- The reproductive rate of an organism
For a new species to arise..
there must be reproductive isolation of a group of individuals from the rest of the population, with each individual accumulating different gene frequencies
speciation
formation of a new species
once two populations aren’t able to breed and produce fertile offspring, they are considered to be two different species
biodiversity
measure of the variety of living organisms and their genetic differences - diversity within animals
genetic diversity
measure of genetic variation found in a particular species
Measuring diversity
- Counting different alleles in a population
- Heterozygosity
Both measures calculated as an average over a number of loci
gene point mutations
alterations of gene base sequence
chromosome mutation
sections of chromosome rearranged during meiosis
independent assortment
is homozygous pair of chromosomes is assorted independently from others during meiosis
crossing-over
Genetic material exchanged between homologous pairs during meiosis resulting in new combo of alleles.
measuring genetic diversity in a species by looking at heterozygosity
Genetic diversity can be measured by DNA sequences
DNA can be cut into fragments then separated using gel electrophoresis
Heterozygous and homozygous can be identified because of the fragments they produce at different lengths
species richness
simplest way is to count number of species present in a habitat.
species evenness
takes into account population size of species – a community in which most of the species have a similar abundance are said to have high evenness, no single species dominates the community
endemic species
species found in one particular region and nowhere in the world.
Biodiversity hotspot
areas of unusually high biodiversity