Evolution Flashcards
Divergent evolution
Two or more species originate from same species and become increasingly different over time.
analogous structures
is a trait or an organ that appears similar in two unrelated organisms (dolphin and shark fin)
anatomical homology
similar body structures among different species from a common ancestor
convergent evolution
process by which unrelated organisms independently evolve similarities when adapting to similar environments
speciation
formation of new species
vestigal structure
a structure that an organism has that is no longer useful to it, but that they have this structure because a common ancestor to that organism found it useful
gene pool
is the set of all genes, or genetic information, in any population, usually of a particular species.
Natural selection
process by which individuals that are better suited to their environment survive and reproduce most successfully; also called survival of the fittest
relative allele frequency
number of times an allele occurs in a gene pool compared with the number of times other alleles occur
artificial selection
Humans choosing which organisms to breed.
homologous structures
evidence that two species share a common ancestor
biodiversity
describes the variation of plant and animal life.
habitat
is a place where an organism lives
Ecosystem
self-sustaining unit made up of a community of living things interacting with and within a particular habitat
species diversity
number of different species within an ecosystem
genetic diversity
range of genetic characteristics within a single species, codes for variation in phenotypes
structural adaptations
structure of an organisms body
behavioural adaptations
change in an organisms behaviour
physiological adaptations
internal function of an organism
if there is no variation what will happen to the species
it will either die out or survive
Darwins theory of evolution by natural selection
1.variation overproduction 2.selection pressure 3survival advantage 4.reproduction and inheritance 5. change over time
variation of genotypes occurs due to what?
mutation meiosis (random assortment of chromosomes into gametes) Crossing over (meiosis)
who were the two scientists that first proposed evolution through natural selection
Darwin and wallace
what is genetic drift
change in allele frequency
adaptive radiation
evolution of many different species from one common ancestor
parallel evolution
when two species arise from a common ancestor because their environments are similar develop similar features
primates
humans, monkeys, apes, oragutans, chimpanzees
ability to walk on two legs is called what
bipedalism
allopatric speciation
geographic separation occurs due to a physical barrier that stops species from interbreeding (river)
sympatric speciation
speciation occurring when the populations are in the same location
humans scientific name is what
homo sapiens
what are fossils
records of life preserved in rocks, they show continuous change
rosellas
divergent evolution
adaptation
is a characteristic of an organism that improves its chance of surviving and reproducing in a particular environment (variations in phenotypes)
as the frequency of favourable alleles in the population increase the population will become
better suited to its environment
steps of natural selection
VSSRC Variation Selection pressure Survival advantage Reproduction Change over time
how can mutations in genes become beneficial
if the environment changes
what defines a separate species
if they cannot reproduce sexually to create fertile offspring
how can we see evolutionary lineage of life
by compaaring various structures
how are fossils formed
when living things are buried they are decomposed and may be preserved. rocks may form around it and mineral fill the gap.
lamarks incorrect laws
the law of use-a characteristic that is used extensively by an organism becomes larger and stronger
the law of disuse-those that are not used eventually disappear
the law of inheritance of acquired characteristics-
an organism could pass these modifications to their offspring
common examples where natural selection has been observed
peppered moth-industrial revolution
3 steps of allopatric speciation
- geographic separation
- natural selection
- reproductive isolation
changes to human skull
environmental conditions were changing rapidly so humans common ancestors were required to do problem solving, so the environment sleeted for those with a bigger brain, they were smarter, could adapt, find shelter and food and reproduce. so they passed on the trait for a bigger brain. the frequency increased now humans have a bigger brain.
3 types of structures
homologous (whale flipper and human limb-divergent evolution)
analogous (convergent evolution)
vestigal
where are the oldest and youngest fossils found
oldest at the bottom
youngest at the top
did humans evolve from apes
no we share a common ancestor
bipedalism
s-shaped spine to be able to walk for longer distances s
what is DNA sequencing?
samples of DNA from different organisms, the number of differences tell you how long go we shared a common ancestor
