unit 5 Flashcards
human relationship general to specific
biggest group- eukaryotes
then animal
then human
most in common with family
what concepts did Linnaeus come up with
the morphological species concept
Binomial nomenclature
what is the morphological species concept
define species based on appearance
what led to us changing from the morphological species concept
evolution since organisms changing means appearance isn’t as important
what is the biological species concept
species is defined on whether organisms can mate with each other and produce fertile offspring
- shares gene pool
-horses and donkeys make mules but mules can’t make more horse or donkeys meaning they have separate gene pools
exceptions to biological species concept
-group of organisms can breed but don’t because of different mating habits
-fertile hybrids ex:lions and tigers can mate but don’t in wild
-asexual organisms-look similar but have genetic or molecular differences
population definition
group of organisms of same species in same place at same time
-different populations that don’t share gene pool are hard to define
ways an organism can change
-# of chromosomes
-change in gene pool
-changes in genome
evolution definition
change in available genes in gene pool leading to new species
what influences evolution
natural selection influences change based on traits best for organism in environment so organism passes it on
-darwinism
what helped to figure out evolution and natural selection
fossils
acquired characteristics-Lamarck ex: giraffe neck
speciation definition
when gene pools have separated and there’s no interbreeding so there is a definite new species
what is reproductive isolation
-organisms are in different places or separated by barrier like a river or lake
-leads to evolution and speciation
how does reproductive isolation lead to speciation
organisms being separated are affected by factors like different climate and predators leading to different adaptations and separates gene pool and stops interbreeding
exceptions to speciation
divergent selection- there are changes but interbreeding is possible
biological species concept
speciation examples
- banobo and chimpanzee
-were moved to different place separated by congo river and gene pools were separated - lava lizards on Galápagos islands
- on different islands
molecular evidence for evolution
-molecules have been conserved and the main 4 are in all living things
-processes conserved
- rate of beneficial mutations fit with rate of evolution
-DNA we have in common w other organisms- common ancestors
what is micro evolution
when microorganisms evolve
-happens fast since they reproduce fast- more mutations
-easily studied
-ex: antibiotic resistance, covid
what is artificial selection
humans picking traits by selective breeding
examples of selective breeding
crops like corn that’s bigger or sweeter
dog breeds based on speed, size
we domesticated wolves into dogs
how is selective breeding evidence for evolution
our ability to do this means nature can as well
homologous structures
body structures that look alike because they came from common ancestors
-ex:pentadactyl limbs- 5 fingers connected to limbs- humans,cats, whales, bats
vestigial structures
have similar structure with organism but no function anymore
-ex: human appendix & tailbone, whale hip bones
analogous structures
similar structures but from different ancestors
-ex:wings- evidence because it is a useful adaptation
convergent evolution
different organisms develop similar traits
-analogous structures
4 statement summary on how natural selection works
- variation
- overproduction of offspring
- increased survival rate for those with better adaptations
- reproduction
how does variation make natural selection work
if all are the same, all will die out if a problem occurs
3 sources of variation
- mutations-create new alleles in DNA
- meiosis- chromosomes get mixed meaning alleles are mixed- segregation and independent assortment
-any allele can go to any offspring
-crossing over when genes are on same chromosome - sexual reproduction-any sperm can fertilize any egg
-same partners or different
how do asexual organisms get variation
mutations
can exchange plasmids-dna- with others of either same species or different
overproduction of offspring leading to natural selection
producing more offspring than environment can support meaning competition occurs and the organisms with better adaptations will survive
ex: giraffes with longer necks are able to eat more and survive
slow breeding organism example
elephants
still overproduce because they live a long time and use a lot of resources leaving offspring with less
fast breeding organism examples
fish and insects
differential survival leading to natural selection
depends on environment
comes from selection pressure
survival depends on how well adapted an organism is
-fitness
fitness definition
the best at surviving no matter the environment
-ex: ability to reproduce
inheritance leading to natural selection
adaptations have to be able to be passed on otherwise they’re acquired and wont lead to natural selection
DNA has to code for adaptations
Sexual selection
What are some ways scientists use fossils as evidence for evolution?
Fossils show how organisms have changed over time and how they are related. Fossils also show extinction which supports the idea of natural selection
