Download Evolution Slides #1

Natural Selection
Variation: Heritability: Overproduction: Reproductive Advantage
Driven by Environment
Factors for Natural Selection:
1. Variation
2. Heritability
3. Overproduction
(Overpopulation)
4. Reproductive Advantage
Evidence of Evolution
1.
2.
The fossil record (link between extinct and existing species… intermediates)
Comparative anatomy
a. Homologous structures (ancestor link) vs
Analogous structures (anatomical similarity)
b. Vestigial structures (kind of homologous structure… reduced forms due to lack of
functional structures)
3.
4.
5.
Comparative embryology (vertebrate embryos exhibit homologous
structures during certain phases of development but become totally different
structures in the adult forms)
Comparative biochemistry (similarity of metabolic molecules and
processes)
Geographic distribution (similarity of species from close ancestor locations)
Fossil Record
Structural (anatomical) adaptation that lead to increased
survival rates of species via evolution.
Comparative anatomy:
Homologous structures vs Analogous structures
Homologous: Underlying anatomical
commonalities demonstrating descent
from a common ancestor. It’s when very
different animals have bones that appear
very similar in form or function and seem to
be related.
Analogous: various structures in
different species having the same
function but have evolved separately,
thus do not share common ancestor.
Homologous structures:
Similar in shape and construction… example of how could be inherited form from
a common ancestor with similar anatomical bone comparisons.
Vestigial Structure
Pelvic bone with femur
Comparative embryology
Comparative biochemistry
Geographic Distribution
Evolution intimately linked with climate and
geological forces… but due to plate
tectonics, species can share a close
ancestor relationship from place of origin
Adaptation:
1.
Morphological adaptations:
●
2.
Camouflage
● Mimicry
Physiological adaptations:
●
Antimicrobial resistance
Bacteria with lots of variation and
ability to adapt can decrease the
effects of penicillin … bacteria
resistance to antibiotics will survive,
reproduce, and pass on their
resistance to the next generation
(natural selection)
Resistance of Corn Rootworm to BT corn plants
Resistance to pesticides/insecticide … Individuals with favorable variations survive
and reproduce … some insects have changed genetically and are unaffected by
pesticides...
Origin of life on Earth
Anaerobic due to lack of oxygen
➔
Prokaryotes (thought to have evolved mitochondria with oxygen use)
◆
Eukaryotes
● Invertebrates
○ Vertebrates
◆ Fishes
Causes of speciation:
●
●
●
●
●
Mechanical isolation… not able to sexually reproduce
Behavioral isolation … ex. Mating behaviors
Habitat isolation
Allopatric isolation … animal populations evolved independently with unique
climates/territory
Changes in climate … ex. Cooler temperatures (Cretaceous period)
Endangered species due to:
Global warming or rapid environmental changes …
not able to adapt
Genetic diversity decreases
Toxins (poisons)
Shaping Evolutionary Theory:
Evolutionary Shaping is
long/slow process (due to
centuries of selective
changes)…
With increase rate of
evolutionary process in a
population note signs of specific
mating and eating habits.
1.
Explain how some of the following evolutionary processes can occur
a.
Gene shuffling:
b.
Directional selection : increase survival rates of the animals… ex Tikaalik roseae via natural selection jointed wrists
c.
Natural selection (“Survival of the fittest” … ability of offspring to reproduce 1st… then amount of food an organism
obtains, and ability to withstand environmental extremes) … no random mutations of genes are occurring, most
members are homozygous for traits, population is above carrying capacity, little inheritable variation of traits
d.
Genetic drift: two new populations (wolf) … over time the presence and distribution of alleles diverge
Change in allelic frequencies
Directional Selection:
Difference between artificially acquired active immunity and naturally acquired
passive immunity:
Humoral and cell mediated immunity adaptive
response: Antigen = Antibody producing response
1.
What are ways a thriving population of organisms are better able to survive (benefit)?
2.
3.
List factors that could lead to species diversity and possibly to a new species.
What is the term that is best defined as “selection of the most fit individuals based on environmental interactions?”
a.
Natural selection
b.
Artificial selection
c.
Selective breeding
d.
Acquired characteristics
An increase in the rate of evolution in a population will be affected by which scenario?
a.
Sunlight stimulates the growth of ash leaves
b.
Wind blows pollen grains to nearby ash trees
c.
Weevils eat the larger seeds dropped by ash trees
d.
Migrating birds rest in ash trees on their journey south
The Tiktaalik roseae fossil was recently discovered. This fossil is of a fish that lived approximately 370 million years ago. It had
scales like fish. Unlike other fish fossils, this fossil has fins with jointed wrists similar to the wrist of a crocodile. Which reason is
the most likely for the natural selection of this type of jointed wrist?
a.
Calcium buildup in bones
b.
Reproduction between various species
c.
Increased survival rates of the animals
d.
Sudden decreases in sea levels
Scientists believe the atmosphere of early Earth was incapable of supporting aerobic organisms. Which best explains this belief?
a.
There was no water in the environment
b.
Photosynthesis was occurring too slowly
c.
Multicellular organisms used up the water
d.
Free oxygen was missing from the environment
4.
5.
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