B10 Biodiversity Flashcards
What’s genetic diversity
number of diff alleles of genes in population.
When can natural selection only occur
if there’s genetic diversity within a population.
What is natural selection
process that leads to evolution in populations.
results in species becoming better adapted to their enviro.
3 types of adaptations
anatomical
physiological
behavioural
Natural selection - process
I. New alleles for gene created by random mutations
- If new alleles increase chances of survival in that enviro, then they more likely to survive and reproduce.
- This reproduction passes on advantageous allele to next gen.
- As result, over many gen, new allele increases in freq in population.
What are the 2 types of selection
Directional
stabilising
Directional selection
• One of the extremes has the selective advantage
• Occurs when there is a change in the environment
• modal trait changes
Stabilising selection
. modal traits has selective advantage
• Occurs when there is no change in enviro
• modal trait remains same.
• Standard deviation decreases, as individuals with extreme trait decrease
Courtship
essential for successful mating and species recognition.
What is a species
group of similar organisms that can breed to make fertile offspring
Species must reproduce, and pass on advantageous alleles, for survival of their species.
Courtship rituals
sequence of actions whichs unique to each species. This how animals identify members of their own species to reproduce with.
Most are performed by males.
can include sequence of dance moves, sounds, release of pheromones, display of colourful feathers or fighting.
Females observe courtship ritual and decide if they want to mate with male.
importance of courtship to ensure successful reproduction
• Enables them to recognise own species and opposite sex
• Synchronises mating behaviour - indicates sexually mature and in season (releasing egg)
Importance of courtship to ensure survivals of the offspring
To ensure survival of the offspring
• Form a pair bond
• Choose a strong and healthy mate
Study courtship rituals
The more similar a courtship sequence is between different species, the most closely related a species are.
For example: 3 duck species courtship rituals
Duck I: Shakes tail → shakes beak → nods and swims → turns to female
Duck 2: Shakes tail → shakes beak → flicks head → turns
Duck 3: Shakes tail → whistles → grunts → raises head and tail → turns to female
Duck I & 2 more closely related, as courtship sequence very similar.
Courtship rituals genetically determined, so more similar species sequence is, more similar their DNA base sequence is.
What’s the binomial system
First name is GENUS, second name is SPECIES.
Same genus shows close relationship.
WHY DO DIFFERENT SPECIES LOOK SIMILAR
- Live in similar enviro
- Have similar selection pressures
- Similar alleles will have selective advantage
- Produces similar/same proteins and therefore have similar characteristics
What is a taxa
Each group of hierarchy
What are classification systems examples of
A hierarchy
What is a hierarchy
Smaller groups arranged within larger groups
No overlap between groups.
Classification systems order
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Why do we need systems to organise the millions of species
Understand relationships between organisms and keep track of changes
system used needs to be universal
Ways to classify
Originally, based on visible similarities- e.g. appearance, behaviour, fossils.
More modern and accurate classification methods are:
- DNA sequence
- mRNA sequence
- Amino acids sequence
- Immunological - comparing similarity in self-antibody shape
Phylogenetic classification
arranges species into groups according to their evolutionary origins & relationships
Phylogeny
tells us who’s related to whom and how closely related they are.
All organisms have evolved from shared common ancestors (relatives).
This shown on phylogenetic tree.
