3. notes and revision Flashcards
biodivesity
Biodiversity is the variety of all life on earth. It includes genetic diversity, species diversity and habitat diversity.
Benefits of biodiversity
economic value
genetic divesity ie increaed survival rate
Humans benefit financially from biodiversity. Natural capital gives us goods that can be sold – such as timber, agricultural food crops, medicines and pharmaceutical drugs and the clothes we wear.
Biodiversity maintains genetic diversity and thus is important to the continuation of evolution increasing survival rate.
Determinants of biodiversity
Climate
Age of the area
habitat range
Age of the area: Older areas tend to have higher biodiversity. This is due to the fact that a longer time-span allows organisms to diversify more and drive greater speciation.
Environmental stability: Some areas of the planet have experienced environmental disturbances (volcanic eruptions, earthquake or floods) and/or climatic disturbances (glaciations or drought) which may destroy large numbers of species. These areas have had less time for colonisation and species adaptation.
Range of habitats: A wide range of habitats will allow the organisms to move into new habitats and ecological niches, therefore evolving and driving speciation.
Species diversity
Species diversity is the richness and evenness of the species.
importance of genetic diversity
Increased survival rate
increased resiliance and adaptation
reduced extinction chances
prevention of inbreeding
There is a better chance that some members of the species will be resilient and survive environmental change caused by things such as disease, climate change and pollution.
Low genetic diversity (often caused by small populations) causes inbreeding which makes the genetic make-up of the population more uniform.
Extinction is frequently preceded by a drop in genetic diversity.
how to measure species diversity
simpsons diversity index
N(N-1) / E n(n-1)
Genetic diversity
Genetic diversity refers to the variation of genes within the genetic pool of a population of a species
Advantages of habitat diversity
Promotes genetic diversity
increases adaptability
leads to speciation thus species diversity
Separation prompts greater variations in the gene pools.This results in higher genetic diversity.
High genetic diversity increases species adaptability and can lead to speciation and thus higher species diversity.
Habitat diversity
Habitat diversity is the range of different habitats in an area.
Speciation
Speciation is the formation of a new species through biological processes.
Factors affecting natural selection
VICS
1. variation -
This is the genetic diversity Within a population of one species
2. Inheritance
The offspring of fitter individuals may inherit the genes that give them that advantage.
3. Competitve advantage
Due to natural variation, some individuals will be fitter than others and therefore have a comparative advantage.
4. survival of the fittest
Fitter individuals are more likely to survive long enough to reproduce more successfully than individuals who are less fit.
Natural selection
Natural selection is the gradual evolutionary change that results from genetic variation in each generation.
ggg
Variation
This is the genetic diversity Within a population of one species
Evolution
The gradual change in geentic chararcter of populations over many generations archived mostly through natural selection
ggg thru natural selection
Steps to natural slection
- Over population
- variation
- selection
- adaptation
Adaptation
this is an inheritred characterist that increases an organisms chance of survival
plate tectonics
this is the continental drift theory that expalins the distribution of continents
Isolation
This is when two populations get separated by environmental cahnges eg sea level change
types of isolation
Geographic - physically separated
temporal - awake at different times of the day
behavioural - different mating rituals
Endemic species
These are unique to a particular location and not found any where else eg lemurs of madagscar ie king julien
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divergent plate margins
divergent margins are where plates move apart and cause diversification
convergent plate margins
where plates move together
Mass extinction
Mass extinction is a sudden global decrease in the number of species over a relatively short period of time.
Background or normal extinction
Background or normal extinction is the standard rate at which species go extinct.
The BIG 5 extinctions
Ordovician-Silurian Extinction (around 445 million years ago):
Cause: Possibly glaciation, climate change, and/or volcanic activity leading to a drop in sea levels and global cooling.
Late Devonian Extinction (around 375-360 million years ago):
Cause: Likely a combination of climate change, oceanic anoxia (low oxygen levels), and habitat loss due to sea-level changes.
Permian-Triassic Extinction (around 252 million years ago):
Cause: Likely volcanic activity from the Siberian Traps, leading to massive global warming, ocean acidification, and habitat destruction.
Triassic-Jurassic Extinction (around 201 million years ago):
Cause: Possibly volcanic activity, asteroid impacts, or climate change, leading to habitat loss and widespread extinction of marine and terrestrial species.
Cretaceous-Paleogene Extinction (around 66 million years ago):
Cause: Most widely attributed to an asteroid impact at Chicxulub, Mexico, leading to massive environmental disturbances, including wildfires, tsunamis, and global cooling due to dust and debris in the atmosphere.
causes of mass extinctions
- Tectonic plate movements
- super volcanic eruptions
- climate change
- meteorite impact
Factors that help maintain biodiversity
AFFECTING MAINTANACE OF BIODIVERSITY
- complexity of food webs
- stages of succesion
- limiting factors
Factors leading to loss in biodiversity
- Natural disaster
- pollution
- fragmentation - division of habitat into fragments
Human activities causing extinction
- over huntin
- pollution
- habitat destruction
determinants of population sttatus or why on the IUCN Red List
- population size
- habitat destruction
- habitat diversity ie if they found in one palce its bad
- reproductivce potential ie r-strategists reproduce alot
IUCN in full
International Union for Conservation of Nature (IUCN)
Flagship species
These species often serve as symbols to raise awareness, garner public support, and mobilize action for broader conservation goals. Flagship species are typically chosen for their appeal to the public and their ability to capture attention, evoke emotional responses, and generate interest in conservation efforts.
Reasons to conserve biodiversity
- ecosytem services
- food sources
- medicines
- ecotourism
conservation vs preservation
Conservation aims to sustainably manage natural resources for human use, while preservation seeks to protect ecosystems and species in their natural state, often excluding human intervention.
