Evolution Flashcards
Geologists
- study the Earth’s structure.
- date rocks by studying chemical elements in rocks;
- age of fossil from age of rock.
Palaeontology
study of plant and animal fossils.
Anthropology
study of human cultural development
Archaeology
study of human activity in the past by studying remains (artefacts) that have been left behind
Fossils
- remains/traces (of hard body parts) of
- organisms that lived millions of years ago
- been preserved into sedimentary rocks
Evolution
process of modifying things that already exist. Change over time.
Homologous structures
features or characteristics shared by a group of species because they were inherited from the same/common ancestor)
Analogous body structures
body structures that do the same job but have a different origin and a slightly different structure, e.g. wings on birds, butterflies and bats
Convergent evolution
when organisms
- not closely related
- evolve similar adaptations
- independently to suit a common environment
Modification by descent
- related species share characteristics (homologous structures)
- inherited them from a common ancestor
Divergent evolution
- evolution of organisms from a common ancestor
- have adapted to changing environments to develop into a new species
Vestigial structures
- small, poorly developed structures that have no real use
- inherited from an ancestor
Biogeography
the study of distribution of living organisms, past and present
Modification within a species
modified descendants of earlier species to adapt to different environments.
Natural selection
- organism best suited to the environment survives
- pass the favourable traits on to the next generation.
- May lead to a new species forming
macroevolution
Type of evolution resulting in the development of a new species
Refers to major evolutionary changes over time
Adaptive radiation
single species diversifying into a variety of different species. organism adapting to a changing environment so that it no longer resembles the parent species
Microevolution
Type of evolution resulting in increased variation at species level
Species
Group of individuals of common ancestry, closely resembling each other, who can interbreed to produce fertile offspring
Embryology
similarities and differences in embryonic development
Comparative anatomy
comparison of structures that show a gradual change /modification of structures that have evolved along the same group line
Inbreeding
Breeding between closely related individuals
in small gene pools - little gene flow between populations
allele frequency increases/ increased homozygosity
genetic diversity decreases/ hybrid vigour
Outbreeding
- interbreeding with other populations
- Formation of stronger, healthier offspring
- adding new alleles to the gene pool
- promotes heterozygosity
Sympatric speciation
- speciation
- populations not geographically isolated from each other
- reproductively isolated
- interbreeding can no longer occur
Founder effect
- when a few members of a species occupy new territories
- isolated from the main population
- resulting in a smaller gene pool showing less variation
Geographical isolation
- physical barriers
- preventing interbreeding
- cause speciation
Evolution
- cumulative change
- long periods of time
Speciation
Development of a new species
microevolution
Type of evolution resulting
- increased variation
- at species level
Gene pool
- all the alleles of a gene
- in a particular population
Mutations
The process by which new types of organisms develop from existing organisms over a long period of time
Genetic Drift
- Is the random changes
- in the (genetic) allele frequency in populations
- may lead to speciation
Evidence of evolution
Fossil record, Homology, Comparative anatomy; Genetic similarities, comparative embryology ; Biogeographic distribution, Biochemical similarities
Punctuated equilibrium
- evolution does not occur gradually
- in sudden bursts (big jumps where phenotypic characteristics change rapidly)
- after long periods of no change (equilibrium/stasis)
Gradualism
model of evolution
- slow, gradual change
- in phenotypic characteristics
Selection pressure
- Factors in the environment
- will select/favour certain individuals
- based on particular characteristic
Artificial Selection
- specific organisms with specific traits/characteristics
- for human use
- are selected to produce offspring with
- desired traits
(Artificial inbreeding and outbreeding)
Allele frequency
the incidence of a gene variant in a population.
Alleles are variant forms of a gene that are located at the same position, or genetic locus, on a chromosome(the number of times a particular gene appears in a population)
Bottle neck effect
- sharp reduction in the size of a population
- due to environmental events
- leads to the reduction in the gene pool
- the prevalence of a particular characteristic
Allopatric speciation
- The formation of a new species
due to the geographical/physically isolation of a few individuals,
- eventually form a new population
- and can no longer interbreed with the original population
Exinct
When all individuals in a species have died and no single organism survives
Extant
Refers to the existence/living of a population/species
Outbreeding
- the reproduction that occurs naturally
- in larger populations
- freely interbreed and exchange genetic material
- leading to greater variation and genetic diversity
Gene flow
- The movement/exchange of genetic material
- between population in different habitats.
- due to interbreeding
Out-of-Africa Theory
homo sapiens originated in Africa
Homo erectus extinct
migrated to other continents
temp, prey, population
Multiregional hypothesis
- Homo erectus occupied different lands
- homo sapiens evolved outside of africa
- independently evolded to the same species
- because when moving, continents allowed for interbreeding
