APES Video Notes 3.3 - Survivorship Curves

Summary

In 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

00:00

🌱 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.

05:02

📊 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.

Keywords

💡Survivorship Curves

Survivorship curves are graphical representations that depict the probability of survival for a cohort of organisms at different age intervals. In the context of the video, these curves are used to illustrate the varying rates of survival among different species, particularly how they relate to reproductive strategies. The video script uses humans and trees as examples to show how survivorship curves can differ significantly between species, with humans generally having higher survivorship rates into old age compared to trees, which face high mortality rates early in life.

💡R and K Selected Species

R and K selected species refer to two different reproductive strategies observed in biology. R-selected species produce many offspring with little parental care, investing more in reproduction than in the survival of each individual offspring. K-selected species, on the other hand, produce fewer offspring but provide more parental care, ensuring a higher likelihood of their offspring reaching maturity. The video script builds upon this concept to explain how these strategies affect the survivorship curves of different species.

💡Parental Care

Parental care refers to the actions taken by parents to provide for the needs of their offspring, which can include protection, feeding, and nurturing. In the video, it is mentioned that the level of parental care is directly related to the survivorship of offspring. For example, humans provide a high level of parental care, which contributes to the high survivorship rates shown on the survivorship curve for humans.

💡Type 1 Survivorship

Type 1 survivorship is characterized by high survival rates early in life, a moderate decline in midlife, and a steep decline in old age. This type of survivorship is associated with K-selected species that provide extensive parental care. The video uses whales as an example of a species with Type 1 survivorship, where many individuals survive infancy and adulthood but experience a sharp decline in old age.

💡Type 2 Survivorship

Type 2 survivorship represents a steady and constant decline in survival rates throughout life. This type is common among species that provide some parental care but are not as protective as K-selected species. The video mentions birds and rodents as examples, where offspring receive some care but are still quite vulnerable to predation and environmental factors.

💡Type 3 Survivorship

Type 3 survivorship is marked by high mortality early in life and a slow decline in survivorship as organisms age. This pattern is typical of r-selected species that produce many offspring with little parental care. The video uses dandelions, insects, fish, and plants as examples, where the majority of offspring die young, but those that survive have a relatively better chance of reaching maturity.

💡Infancy

Infancy, in the context of the video, refers to the early life stage of an organism, typically characterized by high dependency and vulnerability. The survivorship curves illustrate how different species have varying rates of survival during infancy, with some species like humans having high survivorship due to parental care, while others like trees have low survivorship.

💡Adulthood

Adulthood is the mature stage of an organism's life cycle, often associated with full physical development and reproductive capability. The video script discusses how survivorship curves show different patterns of survival as organisms reach adulthood, with some species experiencing a rapid decline in survivorship post-adulthood, like humans, while others maintain relatively stable survivorship, like certain long-lived trees.

💡Old Age

Old age is the final stage of an organism's life cycle, often associated with a decline in health and an increased likelihood of death. The video explains how survivorship curves for different species show varying rates of decline in old age, with K-selected species like whales experiencing a sharp decrease in survivorship, while r-selected species like dandelions have a more gradual decline.

💡Data Analysis

Data analysis, as mentioned in the video, involves examining and interpreting data to identify patterns or trends. In the context of the video, data analysis is applied to survivorship curves to understand and describe the survival patterns of different species. The video script suggests that viewers will practice data analysis by interpreting survivorship graphs and determining which type of survivorship curve the data represents.

💡FRQ

FRQ, or Free Response Question, is a type of assessment often found in standardized tests where students are required to provide detailed answers to questions. The video script mentions that the practice for topic 3.3 will involve describing patterns or trends in data, which is a skill typically honed through FRQs. This suggests that the video's content is not only educational but also preparatory for exams.

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