evolution Flashcards
Unpredictable natural process of change over time with physical change due to genetic modification
evolution
the change in the physical characteristics of a species over several generations.
evolution
based on the idea that all species gradually change over time to be able to adapt to the continuous changing in the environment
natural selection
evolution relies on the process of
natural selection
who proposed natural selection
Charles Darwin
Charles Darwin proposed natural selection upon his observation of the
peppered moth
the population undergoes slow changes over generation
evolution involves descent over time
certain changes in the DNA will affect the physical characteristics of a population
evolution involves genetic modification
these changes occur continuously and gradually
evolution is unpredictable and natural
what supports evolution
fossils
preserved remnants of organisms. One of the richest sources of information about live forms that lived in the past.
fossils
______ of sedimentary rocks in which fossils are located can help determine age of fossils
stratification
A body will decompose unless it is covered by
sediment or volcanic ash
(hard or soft) __________ elements of a body may be preserved from decomposition if they are covered quickly.
hard
Over time, more layers of sediment, ash, or soil are deposited. The hard elements of the organism become ______ by the same minerals that comprise rocks.
mineralized
Occasionally, erosion, uplifting of the earth’s crust, or human excavation may _____ fossils to the surface.
expose
comparing these two structures will be compared to see similarities to existing organisms that it resembles
anatomy of the structure, embryological structures
different origin, same function (the body structure has different origin but same function)
analogous structures
common origin, different function (origin of the structure is the same but it has different functions)
homologous structures
body structure has no function but is homologous to other organisms.
vestigial structure
determining its ________ will contribute to its classification
developmental embryology
determining the similarities between its molecules
biochemistry
this estimates diversions of species from a common ancestor by looking at a certain gene
biochemistry
are rare accidental events that change the nucleotide sequence of a gene.
mutations
This focuses on studying the distribution of plants and animals around the world.
biogeography
may be passed to the next and future generations and without mutation, there will be no evolution or physical changes in the characteristics of an organism.
non-lethal alleles
why is natural selection good
it encourages changes in the gene pool
group of individuals of the same species that occupy the same geographical area
population
random changes in allele frequency due to chance events
genetic drift
2 causes of genetic drift
bottleneck effect, founder effect
Occurs when a major catastrophe wipes out a large proportion of the population without regard to fitness.
bottleneck effect
Occurs when a few individuals leave the group and establish a new population.
founder effect
Redistribution of alleles due to
migration into and out of the
population.
Clue: Covid-19
gene flow
is a phenomenon where a life form dies out completely.
extinction
how many mass extinctions occurs in the last 530 million years?
5
what was the largest mass extinction
permian-triassic
to trace evolutionary change and relationships between species.
evolutionary trees
most recent mass extinction
during the cretaceous period
Evidence of adaptive radiation
story of Darwin’s Finches
The evolution of the finches in the island are a result of _____ of a common finch from south america. In order for them to survive, these finches have evolved depending on its location on the island.
adaptation
short bursts of evolutionary activity or the development of new species within a short time.
adaptive radiation
may simply be traced using a
phylogenic tree
Scientists have proposed a more systematic way of classifying organisms through
taxonomic hierarchy
It follows this system where the most general name of an organism is its domain followed by its kingdom, phylum, class, order, genus, and species. (specific to general)
taxonomic hierarchy
order of taxonomic hierarchy
domain, kingdom, phylum, class, order, family, genus, specie
After the analysis, scientists distinguished our similarities with primates. We only differ in our _____and our ____. Which makes us a close relative.
genus, species
It is safe to say that humans are
primates
these organisms that fall under hominoids have
- larger brain
- no tail
- more complex social behavior
us humans are closest to
chimpanzees
● Appeared in Africa for about 4.4 MYA.
● Most likely the first hominid
● Almost all fossils discovered and upon analysis of its anatomy, it was suggested that it had been walking upright for some of the time based on the shape of its pelvis. However, not all scientists are convinced that these were true hominids. Current debates say that upright postures don’t define hominids.
● only walk upright some of the time.
Ardipithecus ramidus
● Thought to be the direct ancestor of
modern humans
● Appeared in Africa 3.2 MYA with Australopithecus Garhi
● Based on its anatomy and physiology, most definitely walked upright.
● Moreover, males were considerably larger than females. Thus suggesting sexual dimorphism
australopithecus afarensis
● Appeared around 2.4 MYA
● It is the first distinct human ancestor
● Its name or genus and species means
“handy man” as the first stone tools appeared this time
● They are the first tool maker
● The brain in this ancestor is continuously enlarging as long as changes in its physical appearance
like its teeth and facial features.
● It has thick enamels in the teeth which suggests that this ancestor is
an omnivore.
homo habilis
● Appeared 2 MYA
● This group is more human looking
than the rest
● Longer infancy
● Just like homo habilis, it has more
brain enlargement based on the
shape of its skull.
● This group continued to develop its
tool making skills and its social skills
● They have been found in parts of Africa, Europe, and Asia. Giving
its name out of africa
● Fossils of this group have been
discovered along homo heidelbergensis. This group may have become the neanderthals which suggests that they may have coexisted.
homo erectus
● The final phase of human
development was marked by a
substantial increase in brain size.
● For the development in spoken language and development of a physical structure that we would call
human.
● This group is believed to have
developed from Homo erectus and
spread out from Africa.
● It has replaced all the homo species and is the only surviving homo species.
Homo sapiens
● Was discovered in Callao Cave, Cagayan Province of the Philippines
● Based on the analysis of the fossils, it may have lived at least 50,000 to 67,000 years ago.
● This is not included in the diagram.
● The author, who published in nature, favors the view that the new species descends from a homo erectus group whose bodies gradually evolved into forms that are different from those of
their ancestors.
● They have only received the teeth
and have yet to discover the other fossil parts.
Homo luzonensis
are slight changes in the character between subgroups of a common species.
racial differences
All humans belong to a single species, however there are still unique features that distinguish one race from another. These are called
racial differences
