Chapter 22-23 test

Question 1

What is speciation?

Answer 1

The process by which one species splits into multiple species, leading to diversity and linking features of animals

Question 2

What is microevolution and macroevolution?

Answer 2

Microevolution: Changes over time in allele frequencies in a population

Macroevolution: The broad pattern of evolution above the species level

Question 3

What is the biological species concept?

Answer 3

A concept that a species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring with members of other such groups

Question 4

What plays a key role in the formation of new species and keeping them apart?

Answer 4

Gene flow

Question 5

What is reproductive isolation?

Answer 5

biological barriers that impede members of two species from interbreeding and producing viable, fertile offspring

Question 6

In what ways do prezygotic barriers act?

Answer 6

1. impeding member of different species from attempting to mate
2. preventing an attempted mating from being completed successfully
3. if by hindering fertilization from successful mating from fertilization

Question 7

What is temporal isolation?

Answer 7

Species that breed during different times of the day, seasons or years can not mix gametes

Question 8

What is mechanical isolation?

Answer 8

Mating is attempted but morphological differences prevent successful completion

Question 9

What is gametic isolation?

Answer 9

Sperm of one species can not fertilize the eggs of another species. Sperm may not be able to survive in the reproductive tract of females or biochemical mechanisms may prevent sperm penetration

Question 10

What are the types of postzygotic barriers?

Answer 10

1. Reduced hybrid viability: Hybrid is jot fit to survive environment
2. Reduced hybrid fertility: Hybrids are infertile because of gene/chromosome count differences in parents
3. Hybrid breakdown: Some hybrids are fertile and viable, but their offspring are not

Question 11

What are strengths and weaknesses to the biological species concept?

Answer 11

Strength: directs or attention to a way speciation occurs

Weaknesses: There is no way to evaluate reproductive isolation of fossils, it does not apply to asexual organisms and there are organisms that are isolated but experience gene flow

Question 12

What is the morphological species concept? What is a weakness of this concept?

Answer 12

A concept that characterizes species by body shape and other structural features. It is subjective and can create disagreement

Question 13

What is the ecological species concept? How is it different from the biological species concept?

Answer 13

A concept that views a species in terms of its ecological niche, the sum of how members of the species interact with living and nonliving parts of their environment. Unlike the biological species concept, this can accomodate asexual and sexual species and emphasizes the role of disruptive natural selection

Question 14

What is the phylogenetic species concept? What is the weakness of this concept?

Answer 14

A concept that defines a species as the smallest group of individuals that share a common ancestor, forming one branch on the tree of life. This concept can cause sufficiently different species to be classified together and determining the degree of difference necessary is difficult as well

Question 15

What are 2 ways speciation occurs?

Answer 15

Allopatric: Gene flow is interrupted when a population is divided into geographically isolated populations

Sympatric: speciation occurs in populations that live in the same geographic area

Question 16

What is the difference between biological barriers and physical separation?

Answer 16

Even though both inhibit reproduction, biological reproduction is intrinsic to the organism itself

Question 17

what is polyploidy?

Answer 17

An accident in cell division resulting in extra sets of chromosomes

Question 18

What is an autopolyploid?

Answer 18

an individual that has more than two chromosome sets that are all derived from 2 species

Question 19

What is an allopolyploid?

Answer 19

A fertile polyploid that can mate with other allopolyploids, they represent a new species

Question 20

In what organisms is polyploidy common?

Answer 20

Plants, not so much so in animals

Question 21

What role does habitat differentiation play in sympatric speciation?

Answer 21

When genetic factors enable a subpopulation to exploit a habitat or resource not used by the parent population

Question 22

What pattern does a hybrid zone typically follow?

Answer 22

Hybrid zones are present where the habitats of interbreeding species meet, often in groups of isolated patches across a landscape

Question 23

What are the possibilities of a hybrid zone if speciation isnt occurring?

Answer 23

1. Reinforcement: Hybrids are less fit than parent species and natural selection strengthens prezygotic barriers. Barriers are reinforce and barriers between species are strong in sympatric than allopatric populations
2. Fusion: Barriers to reproduction become weaker and the gene pools of the two species become increasingly alike, reverse speciation
3. Stability: Hybrids can continue to be reproduced because they are viable. These are observed where the hybrids are naturally selected AGAINST, because these zones are small and parent species from both populations migrate to this zone

Question 24

What are punctuated equilibria? Why does this occur?

Answer 24

Periods of apparent stability punctuated change in the fossil record. This occurs because changes over shorter periods of time are distinguished in the fossil record

Question 25

What does the fossil record say about speciation rates?

Answer 25

Fossils that display a punctuated pattern suggest that once the process of speciation, it can be completed relatively rapidly

Question 26

What type of evolution do fossils reveal?

Answer 26

macroevolution

Question 27

What are sedimentary rock layers called?

Answer 27

strata

Question 28

What is the fossil record biased towards?

Answer 28

In favor of species that existed for a long time, were abundant and widespread in certain kinds of environments, and had hard shells/skeletons/fossilized parts

Question 29

what is radiometric dating?

Answer 29

One common technique of determining absolute age based on the decay of radioactive isotopes

Question 30

What are stromalites?

Answer 30

Layered rocks that form when certain prokaryotes bind thin films of sediment together

Question 31

What group of organisms did mammals come from?

Answer 31

cynodonts

Question 32

What is the theory of plate tectonics?

Answer 32

A theory that the continents are apart of great plates of earth’s crust that essentially float on the hot, underlying portion of the mantle

Question 33

What process does continental drift promote?

Answer 33

Allopatric speciation

Question 34

What mass extinctions receive the most attention?

Answer 34

Permian(Separating palaeozoic and mesozoic eras) and cretaceous(separating mesozoic and cenozoic eras)

Question 35

What occurred in the permian mass extinction?

Answer 35

Permian: Occurred at a time of enormous volcanic activity in Siberia. Huge amounts of lava covered the earth and enough carbon dioxide was produced to warm the earth and slow the mixing of oceans due to a lower temp difference between poles and equator. This harmed O2 breathing organisms and encouraged growth of anaerobic bacteria that emit poisonous H2S

Question 36

What happened in the cretaceous mass extinction?

Answer 36

A thin layer of clay rich Iridium on the fossil record indicates the falling of extraterrestrial objects to earth.The Iridium at the time formed a cloud that would have blocked sunlight and severely disturbed the global climate for several months

Question 37

What are adaptive radiations?

Answer 37

Periods of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles in their communities

Question 38

Which area is the best example of regional adaptive radiation?

Answer 38

Hawaiian islands

Question 39

What is herterochrony?

Answer 39

An evolutionary change in the rate or timing of developmental events

Question 40

What is paedomorphosis?

Answer 40

A condition where heterochrony alters the timing of reproductive development relative to nonreproductive development, causing organisms to be sexually mature at a different stage than their ancestors

Question 41

What is the function of homeotic genes?

Answer 41

To determine basic spatial features such as wing or leg placement on an organism

Question 42

What are Hox genes?

Answer 42

A class of homeotic genes that provide positional information in an animal embryo

Question 43

What is the cambrian explosion?

Answer 43

The sudden and rapid diversification of animal phyla 535-525 mya

Question 44

What is responsible for change in form of organisms?

Answer 44

Change in the regulation of developmental genes

Question 45

What do the Ubx and Pitx1 genes regulate?

Answer 45

Ubx: body form in insects and crustaceans

Pitx1: Spines in stickleback fish

Question 46

What are exaptations?

Answer 46

Structures that evolved in one context but co-opt for another

Question 47

What is evolution the result of?

Answer 47

Interactions between organisms and their current environments