Bio test (Evolution)

Question 1

The Theory of Evolution

Answer 1

an explanation of how species change over time. this theory suggests that modern species are the result of past changes in genes which were passed down to generations.

Question 2

extinction

Answer 2

mass extinctions decrease the number of species

Question 3

adaptation

Answer 3

Due to gradual, accumalative changes that help organisms survive and reproduce. Adaptations are caused by random genetic mutations in DNA.

Question 4

selective advantage

Answer 4

A genetic advantage that improves an organism’s chance of survival in a changing environment
When an organism has selective advantage, that organism is going to survive and reproduce
Obvious at birth
A mutation can quickly spread in populations because of selective advantage, since bacteria and viruses can reproduce quickly.

Question 4

Structural adaptation

Answer 4

Physical features of an organism
Examples:
Beak variety on birds
camouflage
Mimicry

Question 5

behavioural adaptation

Answer 5

Things organisms do to survive.
Examples:
Migrating to a new area
Mating calls

Question 6

physiological adaptation

Answer 6

Changes or chemical reactions that occur within an organism
examples:
venom
Hibernation (surviving in harsh conditions by keeping warm and preserving energy)

Question 7

what is a scientific law?

Answer 7

a statement based on repeated experiments observations

Question 8

What is a scientific theory?

Answer 8

an explanation that has been aquired through the scientific method and repeatedly tested and confirmed through observation and experiments

Question 9

Survival of the fittest

Answer 9

Fitness: the contribution an individual makes so that its offspring can survive longer and has offspring of its own
Changes that limit survival:
Severe weather
Famine
Disease
Competition for food, space, mates, etc.
The organisms that survive these conditions pass their genes to the next generation, which is why they are called the fittest genes.
If an organism is healthy and survives for a long time, it has offspring that also has its traits, which means it can also survive longer. This shows how that organism is the fittest.

Question 10

Jean-Baptiste Lamarck

Answer 10

He believed that over the time of their lives, organisms adapt to their environment better, as they strive for perfection. He introduces the idea of inheritance of acquired characteristics, meaning that once a organism “perfected” its traits and skills, it will pass that same skill to its offspring

Question 11

Charles Darwin

Answer 11

Proposed the idea of the theory of natural selection, where life changes and continues to change based on natural pressures. he used the survival of the fittest to develop this theory.

Question 12

Natural selection

Answer 12

The process of where characteristics of a population changes over time, and generations that have heritable traits survive for longer periods of times, passing their traits to their offspring.

Question 13

Selective pressure

Answer 13

Environmental conditions select for certain characteristics of individuals and select against others.
Examples:
temperature change
Change in pressure
Change in competitions

Forms of selective pressure:
Biotic and abiotic factors

Question 14

Biotic factors

Answer 14

A living component that affects another organism
Examples: parasites, predators, competition

Question 15

Abiotic factors

Answer 15

Changes in the environment that alter the behaviour in a population
Examples: weather, pesticides, urban vs. rural, antibiotics

Question 16

Artificial selection

Answer 16

Selective pressure exerted by humans on populations to improve or modify desirable traits.

Examples:
cats and dogs are bred for appearance
Cows are bred for more muscle in meat
Chickens are bred to produce more eggs

Reasons why farmers do artificial selection:
increase nutritional value
increase production and the economy for countries dependent on crops
To be drought-resistant and pest-resistant

Consequences:
inherited traits can cause severe side effects
Monoculture: only one type of crop is grown in the same place at the time time, producing identical plants. This reduces genetic diversity which is bad since if theres a disease that inflects a crop, it will affect all of them.
weak soil
more fertilizer
spread of pests
spread of diseases
more pesticides

Positive consequences:
growing requirements
maintenance
pest control
standardized harvesting
Greater yield
gene banks: contains seeds from early ancestors, which are used to modern seeds if it’s needed since they survive for a long time. its goal is to preserve genetic diversity

Question 17

How was evolution proven?

Answer 17

the fossil record
biogeography
anatomy
Embryology
DNA

Question 18

The fossil record

Answer 18

Specific fossils are found within specific layers
(strata) of sedimentary rock
Paleontologists use this to determine dates
The youngest fossils (similar to species alive today) are found closest to the surface and the oldest fossils are found deeper.
Not all organisms appear in the fossil record at the same time
Transitional fossils are always being researched and found to fill in the space between the past and the present, where some organisms developed differently.

Question 19

Vestigial structure

Answer 19

reduces versions of what was once functional structures in an ancestral species

Question 19

Biogeography

Answer 19

The study of the geographical distribution of species
○ Geographically close environments are more likely to have related species
○ Animals found on islands closely resemble animals on the nearest continent
○ Fossils of the same species can be found on the coastline of neighbouring continents

Question 20

Anatomy

Answer 20

Homologous Structures
● Structures that have similar structural elements and origin
● May have a different function
● Originate from a common ancestor
○ Example: hair on mammals

Analogous Structures
● Structures that do not have a common evolutionary origin
● Perform similar functions
● Provide evidence for adaptations to suit the environment
○ Fins on a dolphin vs. fins on a fish

Question 21

Embryology

Answer 21

The study of prebirth stages of an organism’s development
This helps us to see evolutionary ancestors between organisms

Question 22

DNA

Answer 22

comparing genetic sequences can help determine similarity
Two organisms with similar DNA suggests that they inherited these traits from a common ancestor

Question 23

How is each generation different/unique?

Answer 23

independent assortment
crossing over
new random mutations leading to new traits

Genetic variation is random but natural selection isn’t random because fit genes will survive and reproduce

Question 24

Gene pool

Answer 24

A population that consists of all alleles of all genes of each generation.

Question 24

Allele frequency

Answer 24

The number of copies of an allele compared to the total number of alleles in a population

Factors that affect allele frequency:
mutation - change in the DNA of one individual. A heritable mutation (gamete) may affect an entire gene pool

gene flow (migration) - the net movement of alleles from one population to another due to the migration of individuals

Non-random mating - mating among individuals on the basis of a particular phenotype. Inbreeding is another example

Genetic drift - The change of frequencies in alleles due to chance events in a population.

natural selection (most significant) - selective forces affect populations. Theres 4 types of natural selection (stabilizing, directional, disruptive, sex)

More genetic variation in a population = greater diversity = greater chance of selective advantage in a changing environment

Question 24

Microevolution

Answer 24

The change in % of frequency of alleles within a population

Can lead to evolution

Question 24

The founder effect

Answer 24

A new population started by a few members of the original population. The new founders carry most alleles from the original population to the new population.
reduces genetic variation

Question 25

The bottleneck effect

Answer 25

When a population is quickly reduced (from starvation, disaster, etc.) and the surviving organisms start a new population

Question 26

Stabilizing selection

Answer 26

favors intermediate phenotypes and acts against extreme variations of the phenotype

Question 27

Directional selection

Answer 27

favours phenotypes at one extreme over the other (especially in environmental change)

Question 28

Disruptive selection

Answer 28

favours the extremes of a range of phenotypes which can cause the intermediate to be eliminated

Question 29

Sex selection

Answer 29

competition for mates between males through combat or physical appearance

Question 30

Macroevolution

Answer 30

The formation of a new species from an existing species

Question 31

Allopatric speciation

Answer 31

population are seperated by a geographical barrier. gene flow is interruped,

Question 32

Adaptive radiation

Answer 32

diversification of a common ancestral species into a variety of differently adapted species

Question 33

Sympatric speciation

Answer 33

populations in the same geographical area become reproductively isolated (common in plants since they can’t move)

Question 34

Prezygotic isolating mechanisms

Answer 34

eggs cannot be fertilized

Behavioral: species have a specific signal or behaviour that prevents inbreeding (birds have different songs)

Habitat: two species live in the same area but different habitats and do not interact (water vs. open land)

Temporal: some species reproductive organs are incompatible and unable to fertilize

Gametic: a species gametes are not able to fuse to form a zygote (example: sperm cannot survive in the female reproductive tract)

Question 35

Postzygotic isolating mechanisms

Answer 35

Sperm and egg meet but zygote cannot develop into a viable egg

Hybrid inviability: when genetic information is not compatible between species (zygote doesn’t undergo mitosis and cannot develop)

Hybrid sterility: two species can mate but the hybrid is sterile, meaning meiosis fails to produce “normal” gametes (example: horse and donkey create mule, which cannot have offspring)

Hybrid breakdown: two organisms are able to mate and produce viable and fertile offspring, but when the offspring mate (second generation inbreeding), their offspring will be weak

Question 36

Convergent evolution

Answer 36

similar traits arise because different species independently adapted to similar environmental conditions (example: birds and bats both have wings, but they don’t have a common ancestor)

Question 36

The speed of evolutionary change

Answer 36

Gradualism: views evolutionary change as slow and steady (before and after divergence)

Punctuated Equilibrium: views evolutionary history as long periods of equilibrium that are interrupted by periods of divergence

Some species show a gradual change over a period of time while others evolve quickly during the periods of history

Question 37

Divergent evolution

Answer 37

species similar to the ancestral species diverge and become distinct due to changing environmental conditions (example: birds have a common ancestor but they have different types of beaks based on their diet)