APES Video Notes 3.3 - Survivorship Curves
Summary
TLDRIn this educational video, Mr. Speeds discusses survivorship curves, illustrating how different species' offspring survival rates vary with age. He explains the three types of survivorship curves: Type 1, seen in K-selected species like whales with high parental care; Type 2, like birds and rodents with moderate parental care; and Type 3, in r-selected species such as insects with minimal care but many offspring. The video aims to help viewers understand and analyze these curves, emphasizing the importance of relative age units on the x-axis.
Takeaways
- 📚 Today's lesson is about survivorship curves, continuing from the previous topic on R and K selected species.
- 👶 Survivorship curves illustrate the number of individuals from the same species cohort that are still alive at each age.
- 🌳 Humans have high survivorship early in life due to parental care, similar to type 1 survivorship curves.
- 🌱 Trees have low early-life survivorship, like type 3 curves, due to a lack of parental care and environmental challenges.
- 🐳 Type 1 survivorship is characteristic of K-selected species with high parental care and a sharp decline in survivorship in old age.
- 🐦 Type 2 survivorship is moderate, seen in species like birds and rodents, with a steady decline throughout life.
- 🌼 Type 3 survivorship is typical of r-selected species, such as insects and plants, with high early mortality and fewer reaching adulthood.
- 📈 The graph's x-axis represents relative age units, showing the proportion of a species reaching maximum age, not actual lifespan.
- 📊 The steepness of the survivorship curve indicates the rate of death; steeper curves mean higher early mortality.
- 🔍 The lesson's objective is to explain survivorship curves and identify the three basic types: type 1, type 2, and type 3.
- 📝 The FRQ (Free Response Question) practice will involve data analysis to describe and justify survivorship trends from a graph.
Q & A
What is the main topic covered in the video?
-The main topic covered in the video is 'Survivorship Curves', which builds upon the concept of r-selected and K-selected species.
What are the differences between r-selected and K-selected species in terms of parental care?
-r-selected species provide little to no parental care and produce many offspring to compensate for high early mortality, while K-selected species give high parental care, resulting in better survivorship of their offspring.
How is survivorship defined in the context of the video?
-Survivorship refers to the likelihood of individuals to survive infancy and reach adulthood, and it is represented by a survivorship curve.
What does a survivorship curve show?
-A survivorship curve shows a group of individuals of the same species and plots how many of them are still alive at each age.
What are the three basic trends in survivorship curves?
-The three basic trends in survivorship curves are Type 1, Type 2, and Type 3, each representing different patterns of survival rates throughout an organism's life.
Which type of survivorship curve is exhibited by K-selected species?
-K-selected species exhibit Type 1 survivorship curves, characterized by high survivorship early in life due to high parental care.
How does the survivorship of humans, as mentioned in the video, differ from that of trees?
-Humans, as K-selected species, have high survivorship early in life and a rapid decline in old age, whereas trees, which are more r-selected, have low survivorship early in life and fewer individuals survive to maturity.
What is the significance of the x-axis in a survivorship curve?
-The x-axis in a survivorship curve represents time or age, showing the age at which individuals in a cohort are still alive.
Why do r-selected species have a Type 3 survivorship curve?
-r-selected species have a Type 3 survivorship curve because they lack parental care, leading to high early mortality, which they compensate for by producing many offspring.
What is the difference between Type 1 and Type 2 survivorship curves?
-Type 1 survivorship curves show high survivorship early and mid-life with a sharp decline in old age, while Type 2 curves show a steady, constant decline throughout life.
How does the video suggest practicing the skills related to survivorship curves?
-The video suggests practicing data analysis skills by describing patterns or trends in survivorship curves and justifying which type of curve the data represents.
Outlines
🌱 Introduction to Survivorship Curves
Mr. Speeds introduces topic 3.3, focusing on survivorship curves, which builds upon the understanding of reproductive strategies from topic 3.2. He explains that survivorship curves plot the number or proportion of individuals of the same species that are still alive at each age. The video uses human and tree examples to illustrate the concept, showing different survivorship rates. Humans have high survivorship in infancy and a rapid decrease in old age, while trees have low early survivorship due to lack of parental care. The objectives of the lesson include explaining survivorship curves, identifying three basic trends (type 1, type 2, and type 3), and associating K-selected species with type 1 and r-selected species with type 3. The skills practiced include data analysis, focusing on interpreting survivorship graphs and identifying the type of survivorship curve represented.
📊 Analyzing Survivorship Curves
This paragraph delves into the analysis of survivorship curves, emphasizing the relative nature of the age units on the graph. It clarifies that the graph does not imply that all species have the same lifespan but rather shows comparative units of age. The paragraph discusses the FRQ (Free Response Question) practice for the day, which involves describing patterns or trends in survivorship data and justifying which type of survivorship curve the data represents. The video concludes with a reminder to like, subscribe, and check out other videos for further learning.
Mindmap
Keywords
💡Survivorship Curves
💡R and K Selected Species
💡Parental Care
💡Type 1 Survivorship
💡Type 2 Survivorship
💡Type 3 Survivorship
💡Infancy
💡Adulthood
💡Old Age
💡Data Analysis
💡FRQ
Highlights
Today's topic is survivorship curves, building on the concept of R and K selected species.
Survivorship curves show the number of individuals still alive at each age.
Humans have high survivorship through infancy and childhood, but experience rapid decline in old age.
Trees have low early life survivorship due to lack of parental care and environmental threats.
Objective of the video is to explain survivorship curves and their three basic trends.
Survivorship curves represent survival rates for a cohort born at the same time.
Type 1 survivorship is seen in K selected species with high parental care.
Type 3 survivorship is seen in r selected species with low parental care and many offspring.
Type 2 survivorship is intermediate, seen in species like birds or rodents.
Type 1 species have high survivorship early and mid-life, but rapid decline in old age.
Type 2 species experience a steady decline in survivorship throughout life.
Type 3 species have high early life mortality, compensating with many offspring.
The age on the x-axis of the survivorship graph is a relative unit, not absolute.
FRQ practice will involve data analysis and describing survivorship trends.
The video encourages subscribing for future updates and checking out other notes.
The video concludes with the phrase 'think like a mountain right like a scholar'.
Transcripts
hey everybody its mr. speeds and today
we'll be covering topic 3.3 that
survivorship curves so today's concept
is going to build on topic 3.2 which is
R and K selected species so if you
haven't seen that video yet make sure to
take a look at it the link is in the
description below so you want to make
sure to check that out first so like I
said we'll be building on our
understanding of reproductive strategies
here today since are selected and K
selected species differ and how much
parental care they give their offspring
they also differ in the survivorship of
their offspring or how likely they are
to survive infancy and reach adulthood a
survivorship curve shows a group of
individuals of the same species and it
plots how many of them are still alive
at each age the group reaches so we have
a survivorship on the y-axis that's
going to be the number of individuals or
the proportion that are still alive and
then as we go out on the x-axis we have
time so the further out we go here
the older the individuals are as you can
see in this graph most humans are going
to survive infancy childhood and we're
going to reach adulthood but then we're
going to die off pretty rapidly once we
hit old age trees on the other hand have
really low survivorship early in life
barely any tree seedlings survive and
that's because they don't get the
parental care that humans do they're
likely to get stepped on or eaten or
shaded out by other trees and so a much
much much lower proportion of them are
going to survive early in life so let's
take a look at our objectives essential
knowledge and skills for the day our
objective is to be able to explain
survivorship curves and in order to do
that we need to know that they show
survival rates for a cohort or a group
of individuals that are all born at
about the same time we also need to know
that there are three different basic
trends in survivorship that we can see
type 1 type 2 and type 3 and finally we
should know that K selected species are
going to show type 1 survivorship due
their high parental care for offspring
whereas our selected species are going
to show type 3 survivorship due to their
lack of parental care but remember they
have many more offspring to account for
this low survivorship the skills we'll
be practicing in the frq at the end of
the video
today we'll be data analysis so here we
have our classic survivorship graph and
you'll want to note that the three lines
or curves represent the three basic
types of survivorship so remember that
the survivorship curve is just a line on
a graph and it shows the survivorship or
how many individuals are still alive in
a cohort or group of individuals all
born at the same time so the faster the
curve decreases such as these type 3
survivorship organisms like the
dandelion the faster they're dying off
so the fewer of them are surviving early
in life the longer the individuals are
surviving the less dramatic that
drop-off is so if we look at type 1 like
the whale many of those individuals are
surviving early in life in the middle in
life and then we have a really sharp
decline later in life as old age kind of
sits in so with type 1 survivorship
these are our K selected species for the
most part they have high survivorship
early in life because their parents take
such good care of them
and so you could think about like a
mother grizzly bear fiercely defending
her cubs or a mother chimpanzee who's
gonna breastfeed her offspring and keep
us safe from danger by carrying it
around with her
they also have high survivorship in
midlife because once they're fully
developed they're often large organisms
that are capable of defending themselves
either with behavioral adaptations like
living in herds or escaping from
predators or even fighting them off
however they do have a rapid decrease in
survivorship late in life as old age
sets in type 2 are somewhere in the
middle between type 1 and type 3 so just
like there's a spectrum of parental care
there's also a spectrum of survivorship
type 2 species our organisms like birds
or rodents and they typically have a
little bit of parental care early in
life but they're usually smaller
organisms that are less capable of
protecting their young from predators or
they have young that are more sensitive
to disease or temperature so think about
a baby chick or a small rodent without
fur type 2 species
experience a pretty constant and steady
decline all throughout life so just
because a bird survives its fledged
fledgling stage when it's in the nest it
doesn't
I guarantee that it will reach full
sexual maturity or full adulthood type
three now our our selected species and
these are going to be organisms like
insects fish and plants so they provide
little to no parental care which means
they experience very high mortality or
very high death rate early in life they
have to offset this low survivorship or
this high death rate by having lots and
lots of offspring so remember that their
strategy still works they just have to
have a lot of offspring to compensate
for that low survivorship so as I said
very few type three individuals in a
population will make it to middle age
most of them die in infancy or in
childhood once they do there's a
relatively slow decline in survivorship
as time goes on so unlike the type one
species who generally experience a sharp
decrease in survivorship once they hit
old age and one thing I want to point
out here before we move on is that when
we look at this graph the units at the
bottom here age these are relative units
so this graph does not mean that
dandelions are going to live the same
age as whales it just means that
relative to the total maximum lifespan
of a dandelion this percentage of them
will reach their maximum age same thing
with the squirrel and same thing with
the whale so we can show them all on the
same x-axis here because we should know
that these are relative units of age so
even though the whale lives far longer
than a squirrel which generally looks
far longer than a dandelion this is
going to represent comparative units of
age all right
our frq practice for topic 3.3 today
will be data analysis and specifically
we'll be describing patterns or trends
and data so you will need to describe
the trend in survivorship shown in this
graph and justify which type of
survivorship curve these data represent
all right everybody thanks for tuning in
today don't forget to like this video if
it was helpful subscribe for future apes
video updates and check out other notes
over here to the side and as always
think like a mountain right like
a scholar
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