evolution

Question 1

What the 5 causes of evolution?

Answer 1

– small population
-non-random mating
-mutation
-migration
-natural selection

Question 2

Why is a small population a cause of evolution?

Answer 2

-having a small population increases the effects of genetic drift, or the random drift between phenotypes that can occur in a population> This is because it is more susceptible to bottlenecking, which abruptly changes the gene pool and disrupts the allele frequencies.

Question 3

What is the criteria for whether or not microevolution has occurred?

Answer 3

onlu of there are changes in allele frequency?

Question 4

Who is the creater of the uniformitarianism theory and what is this theory?

Answer 4

The earth changes slowly over time
The earth has always changed in the same way

Question 5

what is adaptive radiation?

Answer 5

The process by which a single species or a small group of species evolves over a relatively short time into several different forms that live in different ways.
Example: Galapagos Finches

Question 6

what are analgous structures and what are they evidence of?

Answer 6

-body parts that have different structres but serve similar functions
- an example of convergent evolution

Question 7

what is convergent evolution?

Answer 7

organsims of differnet ancestry are acted upon by selective pressures that favor similar variations

Question 8

what are vestigial structures and why are they evidence of evolution?

Answer 8

vestigial strucures are structures that used to serve a purpose ( which is sometimes seen in other closely related species) but is now useless
-they are body parts that an organism still has but no longer uses for their original function — showing that the organism’s ancestors did use them.

These structures are like evolutionary “leftovers,” proving that species have changed over time.

Question 9

why are embryos evidence of a common ancestor/ diveregent evolution?

Answer 9

-because the embryos of a diverse number of species have similar features due to hox genes, which are gnes that control the body plan of an organism. Later, proteins in the embryo decide which of these genes will be “turned on” as it continues to develop and differentiate. This is evidence of a common ancestor because it suggests that this DNA is more or less the same.

Question 10

what are genetic differences and what are they used for?

Answer 10

The percentage differences between the genomes of species that indicate evolutionary similarities.
-the smaller the percentage, the closer in evolution

Question 11

what is a molecular clock?

Answer 11

A research tool which utilizes mutation rates to approximate the time which species divergence occurred

Question 12

why does divergent evolution occur?

Answer 12

slecctive pressures favor new variations that fill ecosystem niches, and the ancestral organism eventually dies out and fails to reproduce

Question 13

what is gradualism in refernce to the rate of speciation?

Answer 13

slow (gradual) accumulation of new variations/traits over time

Question 14

what is punctuated equilibrium in reference to the rate of speciation?

Answer 14

Short, rapid change punctuated by periods of little to no change

Question 15

what is allopatric speciation and why does it occur?

Answer 15

allopatric speciation is when a geographic barrier separates populations causing divergent evolution over time due to the founder effect

Question 16

what is sympatric speciation and why does it occur?

Answer 16

sympatric speciation is when divergent evolution occurs in the same area due to prezygotic and postzygotic barriers?

Question 17

what are the postzygotic barriers of sympatric speciation?

Answer 17

• there is genetic incompatibility, so the offspring produced is infertile or unfit to survive.

Question 18

what are the 3 types of prezygotic barriers of sympatric speciation?

Answer 18

gametic, behavioral, temporal, and habitat

Question 19

what is a prexzygotic barrier? what is a postzygotic barrier?

Answer 19

a prezygotic barrier is a factor that prevents fertilization within a species, a postzygotic barrier still allows mating and fertilization to occur, but prevents that offspring from serving.

Question 20

what is temporal isolation?

Answer 20

temporal isolation is a prezygotic sympatric barrier that occurs when two populations of a species breed at different times.

Question 21

what is habitat isolation?

Answer 21

a prexygotic, sympatric barrier that occurs when two species live n the same general area, but not in the same exact place

(cor example, amphibians preferring to live on land or in the water)

Question 22

what causes suympatric speciation?

Answer 22

cometition presssures

Question 23

what are hybrids and what are thehy examples of?

Answer 23

hybrids are the offspring between two species and they are an example of postzygotic speciation because they are often born with an uneven number of chromosomes which reduces their ability to reproduce

Examples:
Mules and Hinnies
Ligers and Tigons

Question 24

what makes a species a species?

Answer 24

1. they can interbreed 2. offspring can reproduce?

Question 25

wat is a hybrid?

Answer 25

a corss between 2 different speices that often produces sterile offspring because they are born with an uneven number of chromosomes

Question 26

What are the mechanisms of evolution?

Answer 26

natural/ artificial/sexual selection and genetic drift

Question 27

What are the 5 forms of natural selection?

Answer 27

ecological, directional, stabilizing, disruptive, and sexual selection

Question 28

what is directional selection and when does this occur?

Answer 28

most extreme phenotype is favored -often when there is a natural selection or other inferfence

Question 29

what is stabilizing selection?

Answer 29

the extreme of two pehnotypes is favored

Question 30

What is the theory of biogeography?

Answer 30

-wehre life is from impacts the course of natural selection because different environments favor different mutations

Question 31

What are hte 5 causes of evolution/ change in the allele frequencies of population?

Answer 31

-small population size (because genetic drift doesn't occur in large populations bc they are not as sensitive to bottlenecking) - non-random mating (e.g. sexual, artificial, and natural selection) -mutation (favorable adaptation in the DNA ( or not necessarily favorable in the situations of the founder effect and bottlenecking) -migration -natural selection

Question 32

what is gametic isolation/

Answer 32

a form of prezygotic speciation gametes are incompatible -The sperm is unable to fertilize the egg to form a zygote

Question 33

at is mechanical isolation?

Answer 33

a form of prezygotic isolation in which -Species genitalia are incompatible i.e. “the parts don’t fit”

Question 34

what is coevoution?

Answer 34

The process by which two species evolve in response to changes in each other over time Examples Flowers and pollinators Plants and herbivorous insects Parasites and hosts

Question 35

what is an index fossil?

Answer 35

Fossils that are used in relative dating due to their limited range of existence (time)

Question 36

what is a cast fossil?

Answer 36

a fossil that forms when minerals (e.g. carbonization) fill in a mold, creating a solid copy (replica) of the original organism’s shape.

Question 37

what is an intact remain?

Answer 37

An intact remain is a fossil where the actual organism or parts of it (like bones, teeth, or even hair or soft tissue) are preserved. 🔹 This can happen in amber, ice, or tar, where decay is prevented.

Question 38

what are the 6 thresholds of life?

Answer 38

Photosynthesis (Oxygen Revolution) Eukaryotes (Endosymbiosis) Multi-cellular organisms Development of Brains Inhabit land Mammals

Question 39

What are the oldest living cells?

Answer 39

cyanobacteria

Question 40

waht was the oxygen revolution?

Answer 40

the accumulation of free oxygen in the atmosphere as a result of the first photosynthesizers

Question 42

what is the theory of panspermia?

Answer 42

he seeds of life exist all over the universe and they can be spread to any suitable planet throughout space

Question 43

what is the theory of abiogenesis?

Answer 43

he idea that life originated from non-living substances that organized into the first cell

Question 44

Why and when does natural selection occur/

Answer 44

Occurs in any situation in which more individuals are born than can survive creating a struggle for existence. Genetic diversity creates natural heritable variation.