Ch 4 : Evolution, Biodiversity, and Community Ecology

what is ecosystem diversity?

the variety of ecosystems within a given region ( how many ecosystems exist in a specific area

what is species diversity or biodiversity

the variety of species within a given region

describe species richness .

The number of species in a given area

what is species evenness

measures whether a particular ecosystem is dominated by One Species or all represented by similar numbers of individuals

what two things are used to measure diversity within an ecosystem

species richness and species evenness

what is evolution ?

how the genetic composition of a species changes over time

what is microevolution?

evolution below the species level, small changes in gene frequencies

what is macroevolution?

Evolution that gives RISE to new species or larger groups like a new genera aka speciation

what are genes?

physical locations on chromosomes within each cell of an organism

are genes codes for inherited traits ? and are they always expressed in a physical organism

yes genes are codes for inherited traits, and is NOT ALWAYS expressed in a physical organism

What is the mechanism that underlies all biodiversity

Evolution

what is a synonym for macroevolution

speciation

what is a genotype ?

it is the complete set of genes in an individual

what is a genome?

All of the genes that are in an organism

describe the difference between gene, genome , and genotype

• Gene: a SINGLE instruction in DNA

• Genotype: the SPECIFIC VERSIONS of genes an individual has

• Genome: ALL the DNA in an organism

What is a phenotype?

The set of traits that are ACTUALLY EXPRESSED physically, or biochemically in an individual

give an example of phenotype vs genotype

If someone has the genotype Bb for eye color, their phenotype might be brown eyes.

what is a mutation?

It is a random change in the genetic code,

are mutations positive or negative ?

Some mutations can be advantages or disadvantages

are mutations predictable or unpredictable

Generally UNPREDICTABLE

describe evolution by artificial selection?

It happens when HUMANS determine which traits will be passed onto the next generation and which individuals will breed.

give an example of artificial selection ?

humans often breed dogs and now have more than 400 breeds of dogs

what is evolution by natural selection ?

it happens when the ENVIRONMENT determines which individuals are most likely to survive and reproduce

what is a adaptation?

It is a trait or characteristics which IMPROVES FITNESS in an individual

what is fitness ?

a trait that allows an organism to survive

what is an example of “fitness” ?

speed, color, poison are just a few example of traits that can help individuals survive

what are two book Charles Darwin wrote ?

beagle voyage 1831 -35

on the origin of species (1859)

what are Darwin’s five points of natural selection

1. Animals produce EXCESS offspring

2. Not all of that offspring can survive

3. Animals have different traits

4. The different traits are passed down from parent to offspring

5. Traits that help survival and reproduction become more common.

further explain point #3 in Darwin’s theory of evolution

Individuals vary in inherited traits, and some traits give advantages—like being faster, stronger, or smarter—helping them survive and reproduce.

individuals who are better adapted to the environment are more likely to …

survive and reproduce and pass on their inherited advantage

describe the flow of variation to evolution

mutation & sexual reproduction → variation → natural selection → evolution

what does the pace of evolution depend on

The rate depends on:

• the rate of environmental change

• the amount of genetic variation in species

• the size of the population involved

• how fast the species reproduce

which is better for evolution a slow or fast rate of environmental change

SLOW is better for evolution

is high or low amount of genetic variation better for evolution

HIGHER is better

which is better for evolution a large or small population ?

LARGE POPULATION

Which is better for evolution a species that reproduces slow or fast

FAST

what is the range of tolerance ?

the abiotic (environmental) conditions where a specific species can survive, with peak performance at the optimum conditions.

what is a fundamental niche ?

A fundamental niche is the full “potential job” and living space a species could have in its ecosystem if there were no competition or predators.

what is a realized niche?

the range of abiottic and biotic conditions under which a species lives

what does a realized niche determine ?

species distribution, or areas of the world where the species can live in

what is a niche generalist ?

they are species that live under a wide range of conditions ex.) cockroaches there all over the world

what is a niche specilaist ?

species that live only in SPECIFIC Habitats ex.) Polar bears can only live in the artic

what are fossils ?

the remains of organisms that have been preserved by replacing the organisms minerals to rock

how many mass extinctions have we have in earth history

We have five global mass extinctions were living in the 6th one

what is mass extinctions

when large numbers of species go extinct over a short period time

what was the first mass extinction and when did it occur

Ordovician extinction 440 million years ago 86 % of life lost

what was the deadliest mass extinction

Permian Triassic 252 ma 96 % of life was lost

during what mass extinction did the dinosaurs die

cretaceous Paleogene 66 MA 75% of life died

which mass extinction is mostly die to humans

Holocene 11700 years ago to now

what were the major cause of the first five mass extinctions?

we can only hypothesize the cause

are we currently in a mass extinction?

yes were in our 6th mass EXTERMINATION

what are the levels of complexity that exist in nature

what are 2 factors that regulate population abundance and distribution

population size

population density

define population size ?

the total number of individuals with in a SPECIFIC are at a given time

define population density

the number of individuals per unit area at a given time

what two inputs increase population size

immigration and births

what two outputs decrease population size ?

EMIGRATION and deaths

what is population distribution?

how individuals are distributed with respect to one another

what are the three types of population distribution

random, uniform, clumped

what are the three types of population distribution

what types of factors influence population size

density dependent factors

density independent factor

what are density dependent factors?

factors where the size of the population influence probability of survival

what are density independent factors ?

Factors where the Size of the population has NO EFFECT on the individuals probability of survival

give examples of density dependent factors

animals: food water, nesting sites

terrestrial plants : water, soil nutrients

these factors limit resources and influence individuals survival probability

what are examples of density independent factors ?

hurricanes, floods, tornadoes, concert tickets? ( have the same effect on individual survival regardless of reproduction

what growth models we use to see population density ?

population growth models → equation used to predict population size

growth rate: individuals produced - deaths

intrinsic growth rate : under ideal conditions, unlimited resources (exponential graph)

what type of growth model is this ?

j shaped curve which is a exponential growth model

what is logistic growth model ? and its characteristics

when a population whose growth is exponential FIRST but slows later at carrying capacity

s shapes