Studied by 27 people3 types of evidence for evolution
Molecular evidence (from genetic data and amino acid sequences), experimental evidence (from selective breeding of animals and plants), morphological evidence (from homologous structures)
Homologous structures
structures inherited from a common ancestor which are similar but often used for different functions, shape and number of libs may vary but the general format is the same
Analogous structures
Structures that may have the same function but do not necessarily come from the same body part and do not indicate a common ancestor (eg: wings in eagles, mosquitos and bats)
Evolution
Defined as the process of cumulative change in the heritable characteristics of a population
Lamarckism (Lamarcks theory)
That organisms acquired characteristics through their lifetime and then passed it down to their offspring (experiments he carried out proved him wrong, falsified his theory)
Phylogenic Trees
A simple way to see which organisms are closely related. It can indicate certain similarities and differences between DNA sequences of different species
Selective breeding
Over time breeders have learned to choose the males and females with the most agriculturally desirable genetic characteristics and breed them together
Plant breeding
The selection of planting the plant with the best characteristics
Phylogeny
The way a species has split from other species. It is possible to have two organisms with different phylogenies that share similar physical aspects.
Speciation
The formation of new and distinct species in the course of evolution.
Reproductive isolation
Eventually the two populations that separated will change so much that the individuals from the two separate populations will not be able to reproduce with each other successfully to produce fertile offspring
Geographical isolation
Happens when physical barriers such as land or water formations prevent males and females from different parts of a population finding each other, thus making interbreeding impossible. This barrier can be created by humans (eg: Chinese wall)
Biodiversity
The variety of life found in an area. At it’s best when many types of life forms are present in reasonable numbers (this includes animals, plants, fungi and a variety of microorganisms).
Three levels biodiversity can be studied at
Ecosystem, species and genetics
Ecosystem diversity
Considers diversity from the largest overall viewpoint (eg: The Great Barrier Reef)
Species Diversity
Also called Species Richness, it is the number of different species in a community
Species evennes
A measure of the relative abundance of each of the species in a community. Some of the healthiest ecosystems have both high species richness and evenness though species evenness is often more imporant
Genetic diversity
Every living organism has its own set of genes, giving that organism a unique set of characteristics within its population. Populations with a greater genetic diversity (or a bigger gene pool) are more stable and can better withstand environmental pressures)
Gene pool
All of the gene types or alleles found in the entire population
IPBES
The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services. One of the sources to find info on the current biodiversity crisis.
IUCN Red List
The International Union for Conservation of Nature’s (IUCN) Red List. A continuously updated list of the world’s threatened species. Each assessed species is rated on a scale indicating its ecological health.
How come the human population rate has been declining since the 1960’s, but the human population hasn’t been?
Our lifespan has increased therefore the death rate is declining.
Examples of human population growth effects on biodiversity
Over exploitation of resources, Hunting, Deforestation, Pollution, Increased pest species, Invasive species, Urbanisation, Spread of disease in both humans and other organisms
In situ
Animals original home (eg: managing natural areas)
Ex situ
Conserving living species in mad made environments
In situ efforts to improve biodiversity
National parks, nature reserves, rewilding of areas damaged by human intervention, reclamation of degraded landscapes
Ex situ efforts to improve biodiversity
Breeding programmes by zoos, botanic gardens, seed banks, anima tissue banks
Animal husbandry
The branch of agriculture concerned with animals that are raised for meat, fibre, milk, or other products. It includes day-to-day care, selective breeding, and the raising of livestock.
Animal tissue banks
Two types of tissue: germ plasm (sperm, eggs, embryos, for captive breeding programmes), Somatic tissue (non reproductive tissue samples, for DNA research and possible cloning)
The EDGE of Existence Programme
A global programme launched by the zoological society of London with the goal of selecting evolutionary distinct and globally endangered species.
Process of the selection within the programme of animals
First the IUCN Red list, rating on a species is consulted - Then a score is generated from this lit indicating how endangered the species is - Next the species is evaluated for it’s unique evolutionary history (through DNA sequencing information) - Species that are the most endangered and the most evolutionary distinct are given a high EDGE score, indicating that they should be prioritised
Aim of the EDGE of Existence Programme
To inform governments, conservation organisations and local populations of the ecological peril of different species, they hope that certain animals will be prioritised that they put on their site
Case stuies of organisms threatened by anthropogenic activities
North Island GiantMoa, large herbivorous birds. They were hunted to extinction by the polynesian people around 1200-1300 CE.
Factors of reproductive isolation
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