Biology Exam Review

Question 1

Why do cells divide in mitosis?

Answer 1

1. Growth
2. Repair
3. Reproduction

Question 2

What happens in Interphase?

Answer 2

There are three parts of interphase, Gap 1, Synthesis, Gap 2.
In G1 and G2 the cell grows.
In synthesis, the genetic material is duplicated.
There are checkpoints to make sure DNA duplicated properly.
The genetic material is inside the nucleus (chromatin).

Question 3

What happens in prophase I?

Answer 3

The chromosomes get paired, then condense. The spindle fibers form. The centrioles will move to opposite poles. Synapsis happens (Homologous chromosomes create tetrad which is 4 chromatids. Recombination/crossing over happens. The place/site they will cross over is called chiasma.

Question 4

What happens in metaphase I?

Answer 4

The tetrads line up in/along the equator in a random assortment (independent assortment). The spindle fibres attach to the the pair of sister chromatids.

Question 5

What happens in Anaphase I?

Answer 5

The sister chromatids do not separate here (differs from mitosis)
Although, the pairs of chromosomes move apart to opposite poles.

Question 6

What happens in Telophase I?

Answer 6

Cytokinesis happens, creating two genetically different daughter cells.
Each daughter cell has half the number has half the number of chromosomes as the parent cell (haploid-n)

Question 7

What happens in prophase II?

Answer 7

The nuclear envelope breaks and the spindle fibres start to form.

Question 8

What happens in Metaphase II?

Answer 8

Chromosomes align in the along equator of the cell.

Spindle fibres attach to centromeres of sister chromatids.

Question 9

What happens in Anaphase II?

Answer 9

Spindle fibres contract and pull sister chromatids apart.

Question 10

What happens in Telophase II

Answer 10

Nuclear envelope assembles.
chromosomes decondense.
Spindle disappears.
Cytokinesis divides each cell into two.

Question 11

What is the result of meiosis?

Answer 11

4 non identical haploid gamete cells.
1 copy of each chromosome
1 allele of each gene
Different combinations of alleles for different genes along the chromosomes.

Question 12

What is Evolution?

Answer 12

The change in inherited traits in a population over time.

Question 13

What is microevolution?

Answer 13

Small changes within a population or species. These changes happen over a short period of time.

Question 14

What is macroevolution?

Answer 14

Large changes in organisms over a long period of time.

Question 15

What is gene pool?

Answer 15

The total collection of alleles in a population at any one time. Gene pool can be measured by allele frequency.

Question 16

What is population?

Answer 16

A population is a group of individuals of the same species living in the same place at the same time. Populations are the smallest unit that can evolve.

Question 17

What are the non random changes of microevolution?

Answer 17

Natural Selection, Artificial Selection, Sexual Selection

Question 18

What are random changes in microevolution?

Answer 18

Mutations, Genetic Drift, Gene Flow.

Question 19

What are the four points of natural selection?

Answer 19

1. Variation - There is Variation that already exists in a population.
2. Competition/Struggle - overpopulation causes struggle for existence (food, water, territory)
3. Environmental Selection - Environment selects fit variant
4. Reproduction and Inheritance - The variation passed on to next generation

Question 20

What are adaptations?

Answer 20

A structural, physiological or behavioral trait that improves an organism’s fitness in it’s environment.

Question 21

What are structural adaptations

Answer 21

Anatomical changes in the shape or arrangement of particular features.
An example can be arrangement of teeth, shape of fins or beaks.
Another example is mimicry, mimicry is the ability of one species to resemble another species that may be dangerous to the prey.

Question 22

What are physiological adaptations?

Answer 22

adaptations that are associated with the changes in biochemical functions inside organisms.
For example spider webs, antibiotic resistance in bacteria.

Question 23

What are behavioral adaptations?

Answer 23

Behavioral adaptations are how organisms respond to their environments.
For example migrations.

Question 24

What is artificial selection?

Answer 24

Directed breeding in which individuals that exhibit a particular trait are chosen as parents of the next generation. Artificial selection is used to produce new breeds or varieties of plants and animals.

Question 25

What is sexual selection?

Answer 25

Favors selection of any trait that influences mating success of an individual.

Question 26

What is Intrersexual selection?

Answer 26

males compete to be chosen by females, females choose mates by physical or behavioral features (bright coloration or songs).

Question 27

What is Intrasexual selection?

Answer 27

Male to male competition, males compete amongst themselves.

Example, best fighting style, largest body size.

Question 28

What is sexual dimorphism?

Answer 28

Morphological differences between males and females of the same.

Question 29

What is allele frequency?

Answer 29

The frequency of the allele compared to the total alleles found in that population.

Question 30

What is the Hardy-Weinberg Principle

Answer 30

Allele frequency will not change from generation to generation as long as
1. The population size remains large
2. Mating opportunities are equal
3. No mutations occur
4. No migrations occur
5. No natural selection occurs.
(All individuals have an equal chance of reproducing)

Question 31

What is genetic drift?

Answer 31

When there are changes in allele frequency due to chance
An example is when a natural disaster happens - the survivors don’t survive because they were suited for the environment better, but rather because they were lucky. The alleles that are present in the survivors are only a (random) sample of those of the original population.

Question 32

How does genetic drift tend to fix alleles?

Answer 32

Genetic drift tends to fix alleles because they are the only allele left in the population meaning allele frequency is 100 percent. Although genetic drift doesn’t have to fix alleles. Genetic drift also reduces genetic diversity.

Question 33

What is bottleneck effect.

Answer 33

A dramatic, often temporary, reduction in population size. Only a small sample of alleles survives to establish the new population.
The surviving individuals often do not reflect the allele make up of the original population and due to that genetic drift happens.

Question 34

What is founder effect?

Answer 34

Founder effect is when a small number of individuals isolate themselves from their original population and establish a new one. The genetic variation will not be the same as the original population.

Question 35

What is gene flow?

Answer 35

Gene flow is the movement of alleles from one population to another by permanent migration or mating between populations without permanent migration.
Genetic information is shared between populations.
The difference between gene flow and genetic drift is that gene flow reduces the differences between populations because new alleles may be introduced to one population and alleles may be lost from another population.

Question 36

What is species biologically?

Answer 36

Species biologically is a group of similar individuals that are capable of interbreeding that produce fertile offspring.

Question 37

What is species evolutionary?

Answer 37

They are members of interbreeding groups or populations that are reproductively isolated from other groups and evolve independently

Question 38

What is speciation?

Answer 38

It’s the process by which new biological species arise.

Question 39

What are Reproductive isolating mechanisms?

Answer 39

Any behavioral, structural or biochemical trait that prevents individuals from reproducing successfully together.
Some are due to the traits of the organism
Some are due to environmental circumstances

Question 40

What is allopatric speciation?

Answer 40

Allopatric speciation is when populations of a species become geographically isolated. Often a physical barrier between two populations.

Question 41

What is sympatric speciation?

Answer 41

Its the evolution of populations within the same geographic area into separate species.
Gene flow is reduced between populations.

Question 42

What is adaptive radiation?

Answer 42

Adaptive radiation is the possible result of allopatric or sympatric speciation.
It’s when a single species evolve into a number of distinct/closely related species in one speciation event.
Each new species fills a different ecological niche
Usually occurs when a variety of new resources becomes available.
Increases biodiversity.