Natural selection Flashcards
What were Darwin’s four main ideas?
- organisms that reproduce sexually show great variety in appearance
- organisms produce an excess of offspring so there’s always a competition between members of species
- organisms inheriting characteristics that give them an advantage in this struggle are most likely to survive and pass on desired feature to offspring
- organisms inherits disadvantageous characteristics will be more likely to die before reproducing
What do anatomical adaptations involve?
Form and structure of organism
What do physiological adaptations involve?
The way the body works and include differences in biochemical pathways or enzymes.
What do behavioural adaptations involve?
Changes to programmed or instinctive behaviour making organisms better adapted for survival.
What contributes to the problem of antibiotic resistance? (4)
- too widely prescribed
- some people don’t complete course
- in some countries it’s used int he food chain
- no big incentive for pharmaceutical companies to develop new ones because they’ll be barely used to prevent development of more resistance.
How are we trying to win the pathogen vs antibiotic race? (4)
- reduce use
- better education so people know they don’t always need antibiotics
- reduce use in farm animals
- DNA sequencing will help identify bacteria
Give and explain five isolating mechanisms.
- geographical: physical barrier separates individuals from an original population
- ecological: two populations inhabit same region but develop preferences for different parts
- seasonal: timing of flowering or sexual receptiveness in some parts drifts away from norm, leading to different time frames of reproduction
- behavioural: courtship ritual, display or mating pattern changes so they don’t recognise them as a mate anymore.
- mechanical: genitalia mutation makes it physically possible to only mate successfully with some members,.
What is allopatric speciation?
Population is physically or geographically separated.
What is adaptive radiation?
Process where one species evolves quickly to form a number of different species which all fill different ecological niches.
What is sympatric speciation?
Same place, mechanical, behavioural or seasonal changes.
How is sympatric speciation different to allopatric?
Sympatric species are closely related and occupy overlapping ranges, and gene flow continues to some extent as speciation takes place.
What characteristics of places leads to high biodiversity? (3) and why
- stable ecosystems as this allows many complex relationships between species
- area with high productivity levels (psynthesis levels) as it can support more niches
- areas wehre organisms can grow and reproduce quickly, as it’s more likely we’ll have mutations leading to adaptations allowing organisms to exploit more niches .
Why are endemic populations vulnerable?
Usually high species biodiversity but low genetic diversity so they’re vulnerable to disease.
Why is genetic biodiversity also important?
Because without variety a population is vulnerable.
Ethically, why maintain biodiversity? (4)
- if we destroy is we are denying future generations use of the renewable natural resources
- it’s a great source of pleasure so should be maintained
- when species becomes extinct unique combinations of DNA are lost. Loss of biodiversity due to human activities is unethical.
- Humans have the potential to cause mass extinctions through climate change and this interference is UNETHICAL.
