Ecological Succession (primary vs secondary)

Summary

This script explores ecological succession, using the analogy of U.S. Presidents to explain the concept of succession as a process of following and coming next. It delves into primary succession, the development of life on barren land such as new volcanic rock or retreating glaciers, and secondary succession, the recovery of an ecosystem after a disturbance like a forest fire. The script vividly describes the stages of these processes, from pioneer species like moss and lichen to climax communities, emphasizing the gradual and dynamic nature of ecological change.

Takeaways

• 📚 Ecological succession is the process of ecological development in an area, starting from bare rock to a mature ecosystem.
• 🇺🇸 Succession means to follow or come next, as illustrated by the analogy of American presidents succeeding one another.
• 🌋 Primary succession begins in a lifeless area such as bare rock created by a volcanic eruption or glacial retreat.
• 🌱 Pioneer species, like moss and lichen, are the first to colonize barren environments, breaking down rock into soil.
• 💨 Moss and lichen arrive via wind-blown spores, starting the soil formation process.
• 🌸 Over time, soil builds up, allowing small plants, grasses, and shrubs to grow, followed by herbivores and then carnivores.
• 🌳 With more time and decomposition, richer soil supports larger plants and trees, leading to a more complex ecosystem.
• 🌲 The climax community is the final stage of ecological succession, where a stable, mature ecosystem is established.
• 🔥 Secondary succession occurs after a disturbance in an existing ecosystem, like a fire, and regrowth happens faster due to remaining soil.
• 🏞️ Natural disasters like floods, hurricanes, tsunamis, mudslides, and volcanic eruptions can lead to secondary succession, as can human activities like abandoning a town.

Q & A

What is the meaning of 'ecological succession'?

Ecological succession refers to the process by which an ecosystem changes over time, with different species replacing one another until a stable community is established.

What is the analogy used to explain the concept of 'secession' in the script?

The analogy used is the succession of American Presidents, where each president 'succeeds' or follows the previous one in office.

What are the two main types of ecological succession discussed in the script?

The two main types of ecological succession discussed are primary succession and secondary succession.

What is primary succession and how does it start?

Primary succession is the process of ecosystem development in an uninhabited area, starting from bare rock or newly formed land, and gradually progressing to a mature ecosystem.

How does the process of primary succession begin on a barren rock?

Primary succession begins on a barren rock when pioneer species like moss and lichen colonize the area, often carried by wind or through spores.

What are some real-world examples of primary succession mentioned in the script?

Examples of primary succession mentioned include new land formed by volcanic eruptions in the Hawaiian Islands and the retreat of glaciers exposing new barren land.

What role do pioneer species play in primary succession?

Pioneer species are the first organisms to inhabit new land in primary succession. They help to create a thin layer of soil through decomposition, paving the way for more complex plant life.

What is secondary succession and how does it differ from primary succession?

Secondary succession occurs after a disturbance in an established ecosystem, such as a forest fire. Unlike primary succession, the soil remains intact, allowing for a faster recovery and regrowth process.

What are some natural disturbances that can trigger secondary succession?

Natural disturbances that can trigger secondary succession include forest fires, floods, hurricanes, tsunamis, and volcanic eruptions.

How does the script illustrate the process of secondary succession after a forest fire?

The script illustrates secondary succession after a forest fire by showing a series of pictures taken at different years post-fire, demonstrating the gradual regrowth of vegetation and the return of wildlife.

What is the final stage of both primary and secondary succession called, and what does it represent?

The final stage of both types of succession is called the climax community. It represents a stable ecosystem where plant and animal populations exist in balance with one another.

Outlines

00:00

🌱 Introduction to Ecological Succession and Presidential Analogy

The video begins with an introduction to ecological succession, using a presidential succession analogy to explain the concept of 'succession' or 'secede,' which means to follow and come next. The analogy outlines the succession of American Presidents from Ronald Reagan to Joe Biden. This sets the stage for understanding ecological succession as a process where ecosystems develop and change over time.

05:01

🌋 Primary Succession: From Bare Rock to Ecosystem

The video then discusses primary succession, starting with a barren rock surface that eventually transforms into a rich ecosystem. Using the example of volcanic eruptions in the Hawaiian Islands, it explains how lava cools to form new land that gets colonized by life over time. Glacial retreat is another example where exposed rocky land is eventually inhabited by vegetation. The McCarty Glacier example illustrates how land exposed by retreating glaciers becomes vegetated over time.

10:01

🦠 Pioneers of Primary Succession

The next section introduces pioneer species, the first organisms to colonize new land. Analogies to famous pioneers in history help explain the concept. Pioneer species such as moss and lichen, which can colonize bare rock, play a crucial role in creating soil from their decomposed organic matter. This sets the foundation for other plants and eventually larger vegetation to grow.

🌾 Development of Vegetation and Arrival of Herbivores

As more time passes, the thin layer of soil created by pioneer species allows more plants to grow. Seeds arrive through wind or animal droppings, leading to the growth of small flowers, grasses, and shrubs. Herbivores then migrate to the area in search of food, followed by carnivores, creating a growing community. The continual decomposition of plant material enriches the soil, supporting even more plant life.

🌳 Formation of Climax Community

Over decades, the soil becomes thicker and more nutrient-rich, allowing trees to take root and grow to full maturity. This creates habitats for various animals, leading to a balanced climax community where plant and animal populations stabilize. The final stage of primary succession results in a mature ecosystem that may take centuries to develop fully.

🔥 Secondary Succession: Regrowth After Disturbance

The video then shifts to secondary succession, which occurs after a disturbance in an established ecosystem, such as a forest fire. Unlike primary succession, the soil remains intact, allowing for faster regrowth. Stages of regrowth occur similarly to primary succession but at an accelerated pace. Examples include forest regrowth after fires, floods, hurricanes, tsunamis, mudslides, volcanic eruptions, and human abandonment of areas like Pripyat after the Chernobyl disaster.

🏞️ Examples and Summary of Secondary Succession

The video provides visual examples of secondary succession, showing how vegetation regrows in stages after a forest fire. It also discusses how life returns after other natural disasters and in abandoned areas. The process of secondary succession is faster because it builds on the existing soil, leading to quicker recovery of the ecosystem. The video concludes with a quiz to test understanding of the concepts covered.

Keywords

💡Ecological Succession

Ecological succession is the process by which ecosystems change and develop over time. It is central to the video's theme as it explains how communities of organisms replace one another in an environment. The script uses the analogy of American Presidents to illustrate the concept of succession, and it discusses both primary and secondary succession as stages in the development of an ecosystem.

💡Primary Succession

Primary succession refers to the process of ecosystem development in an area where no life previously existed, such as on bare rock. The video script describes primary succession in detail, starting with the colonization of barren land by pioneer species like lichen and moss, and eventually leading to the establishment of a climax community, such as a forest, over a long period of time.

💡Pioneer Species

Pioneer species are the first organisms to colonize an area undergoing primary succession. They are typically hardy and able to survive in harsh conditions. The script uses the analogy of human pioneers, like Alexander Fleming and Amelia Earhart, to explain the role of these species in forging paths for other life to follow, such as moss and lichen colonizing new rock surfaces.

💡Climax Community

A climax community represents the final, stable stage of ecological succession, where a balance of plant and animal populations is achieved. The video script describes how, after many years of development, an ecosystem reaches this stage where it is self-sustaining and species diversity is high, as seen in the transition from a barren rock to a thriving forest.

💡Secondary Succession

Secondary succession is the process of regrowth and recovery in an area where an established ecosystem has been disturbed, such as by a forest fire. The script explains that this type of succession happens more quickly than primary succession because the soil and some organisms remain intact, allowing for faster reestablishment of plant and animal life.

💡Decomposition

Decomposition is the process by which organic matter is broken down into simpler components, enriching the soil with nutrients. The script mentions decomposition as a key factor in building up soil layers and nutrients, which supports the growth of more complex plant life and contributes to the development of an ecosystem over time.

💡Herbivores

Herbivores are animals that feed on plants and are an integral part of an ecosystem's food chain. The script discusses how, as plant life becomes more established during succession, herbivores migrate into the area, which in turn attracts carnivores, illustrating the interconnectedness of ecological communities.

💡Carnivores

Carnivores are animals that feed on other animals, typically herbivores. The script explains that the presence of herbivores in an area undergoing succession will eventually lead to the arrival of carnivores, highlighting the predator-prey relationships that develop as an ecosystem matures.

💡Natural Disasters

Natural disasters, such as forest fires, floods, and hurricanes, can cause disturbances in ecosystems, leading to secondary succession. The script provides examples of how different natural disasters impact ecosystems and the subsequent recovery process, emphasizing the resilience of nature to regenerate after such events.

💡Abandoned Areas

Abandoned areas, like the city of Pripyat post-Chernobyl disaster, are examples of how nature reclaims spaces when human activity ceases. The script uses the image of an overgrown soccer stadium and the regrowth in ghost towns to illustrate the concept of secondary succession in human-abandoned environments.

💡Soil

Soil is the upper layer of the earth's surface that supports plant life and is critical for ecosystem development. The script discusses the importance of soil in both primary and secondary succession, explaining how the accumulation of organic matter and nutrients in the soil supports the growth of more complex plant communities.

Highlights

The video discusses the concept of ecological succession, using the analogy of American Presidents to explain the term 'secession'.

Primary succession is the establishment and development of an ecosystem in an uninhabited area.

The process begins with bare rock, which over time, develops into a thriving ecosystem through a series of changes.

Volcanic eruptions and glacial retreat are examples of events that lead to primary succession.

Life colonizes new barren land through primary succession, as seen in the Hawaiian Islands where volcanic lava solidifies into new rock.

The process starts with pioneer species like moss and lichen, which are the first organisms to inhabit new land.

Pioneer species are carried by wind and grow on rocks, eventually forming a thin layer of soil.

As time passes, more moss and lichen grow, creating a thick layer that further develops the soil.

Seeds are introduced to the area through bird droppings and wind, leading to the growth of small flowers, grasses, and shrubs.

Herbivores and carnivores migrate to the area as vegetation increases, forming a growing community.

Decomposition of plant material and animal waste continually builds up the soil, enriching it with nutrients.

As the soil becomes richer, more plant life grows, and the community becomes more established.

Decomposition and soil enrichment lead to the growth of trees, which eventually form a climax community.

The climax community is the final stage of primary succession, where plants and animal populations exist in balance.

Secondary succession occurs after a disturbance in an established ecosystem, such as a forest fire.

Unlike primary succession, secondary succession does not start from scratch because the soil remains intact.

Regrowth in secondary succession occurs at a faster pace, often taking just a few decades.

Examples of natural disasters that can lead to secondary succession include floods, hurricanes, tsunamis, and volcanic eruptions.

Abandoned areas, like the city of Pripyat in Ukraine, also undergo secondary succession as nature reclaims the land.

Transcripts

hello everybody so the topic of this

video is going to be ecological

succession let's go ahead and get

started

so what does the word secession even

mean I want to use an analogy with

American Presidents this is President

Ronald Reagan he was President until

1988. who seceded him in 1989. that was

George Bush

who seceded President Bush in 1993. that

was Bill Clinton who seceded Bill

Clinton in 2001 that was George Bush Jr

who seceded him in 2009 that was Barack

Obama who seceded him in 2017 that was

Donald Trump and who seceded him in 2021

that was Joe Biden so I hope you see

secession or secede means to follow and

come next I hope you'll understand why I

chose this analogy as I go through the

slideshow

so let's get into the process of primary

succession first The Establishment and

development of an ecosystem in an

uninhabited area well here's a patch of

bare rock well over time an ecosystem

will develop through a series of changes

and it's subtle at first small

vegetation at first but then the

vegetation grows and gets more hearty

and eventually perhaps you end with a a

large Forest well how does this process

happen let's talk about this in more

detail

so let's look at this example here we

have a volcano erupting and lava is

flowing into the ocean well eventually

this lava will cool down and solidify

into new rock new Barren land now

eventually because of primary succession

life will colonize this area so this is

what we're going to follow a little

later in the slideshow

and this exact scenario is happening in

the Hawaiian Islands volcanoes are

erupting and spewing out lava that lava

is flowing into the ocean and when it

solidifies it makes new uh Barren Rocky

lands that eventually become colonized

through primary succession

you know another scenario that leads to

primary succession is what is called

glacial Retreat as the seasons change as

the planet goes through periods of

warming and cooling glaciers when uh

through warming periods will Retreat and

when that happens new Barren Rocky land

is exposed that eventually becomes

colonized by life

you know here's a nice picture showing

glacial Retreat even though the picture

itself is from 2003 and a little old but

in the blinking line right there this is

where the glacier was in 1985. even now

today I'm sure this Glacier is even

retreated further exposing more land

so here's a good picture of the McCarty

Glacier taken from 1909 and if we if we

compare that to a picture from 2004 the

glacier has retreated but notice the

green hillsides the Green Mountain sides

vegetation has colonized this land

okay so let's actually start the process

now of primary succession starting at

the beginning we're going to use the

volcano lava example so this lava will

eventually cool and Harden into a rocky

Barren Wasteland

and so in my animation here we have some

molten lava that has just gone through

Cooling and now this is just a Barren

Rocky Wasteland let's begin the process

now

so let's go ahead and introduce the

Pioneers now I want to use an analogy

people can be Pioneers these are people

who are Trailblazers they Forge paths

for others to follow you know perhaps

you've heard of Alexander Fleming he was

a Pioneer in medicine he helped to

develop the first ever antibiotic called

penicillin

Amelia Earhart was a Pioneer who helped

uh who was a Trailblazer for women in

aviation uh Elvis Presley was a Pioneer

in rock and roll

a former tennis player Billie Jean King

a Pioneer in women's rights and lgbtq

rights and Muhammad Ali a Pioneer in the

Civil Rights Movement these are people

who are Trailblazers and I hope you'll

understand why I chose this analogy as

we go through pioneer species next

so in primary succession the

Trailblazers are the pioneer species the

first organisms to inhabit this new land

typically you'll see moss which you can

see in this picture growing on rocks and

lichen which you can also see growing on

rock and in this environment that's all

there is this is just a rocky Wasteland

so moss and lichen colonize this new

area

so how do the Moss and lichen even

arrive in this new area well they're

carried by the wind moss and lichen will

release little reproductive cells called

spores the spores of land and ultimately

they begin to grow

now lichen comes in these colors right

here the silvers and reds yellowish

greenish colors kind of these pale

colors here and and this Rusty orange

color right here and so in my animation

I drew the like and as these colorful

squiggly squiggly lines that have begun

to grow on the rock

now over time as the years and years and

years pass the like and will will

multiply and eventually die and the

organic remains forms a real thin layer

of soil over the years and years and

years that pass now is this enough soil

for large sequoia trees and redwood

trees to begin to grow no but it's

enough soil and nutrients for even more

moss and lichen to begin to grow and you

get this real thick Shaggy almost a

thick Shaggy layer of carpet that begins

to grow on the rocky land

so as more time passes as the years and

perhaps decades pass eventually seeds

enter the area you know as birds are

flying overhead seeds often get

deposited in their droppings here's

another bird right here that just went

poop and a seed came out and eventually

was deposited in this area

seeds can also be deposited and

dispersed through wind many seeds are

wind dispersed and can be spread through

the wind and when they land they begin

to germinate into small flowers and

grasses and shrubs begin to grow again

this process can take years and years

and years and decades

so now that there's plans and vegetation

in the area as more time passes

eventually the herbivores begin to

migrate in in the search for food and

shelter and where herbivores migrate

eventually of course carnivores then

follow and we have a growing Community

you know 60 70 years ago perhaps this

was just a rocky Wasteland and as more

time passes decomposition of plant

fallen leaves of plants and mouse

droppings and snake droppings and the

petals that fall off of flowers

decomposition continually builds up the

soil and more and more and more

nutrients are packed away that

eventually help to spawn even more

growth so as more time passes the soil

becomes more rich and more plant life

begins to grow and the community becomes

even more established

so as even more time passes

decomposition again continually builds

the soil notice how the soil just became

thicker as years and years and decades

pass now that the soil is thicker and

more nutrient Rich trees begin to take

root the seeds get deposited by wind and

bird droppings and they grow and it

takes years perhaps decades for trees to

reach their full maturity but eventually

now that there's more habitats and trees

to live in animals migrate in other

animals migrate in and take advantage of

an open Niche that perhaps didn't exist

before and so some insects have flown in

and perhaps some birds and this slow and

steady process can take years and years

and decades but let's say 120 years ago

what was this world it was a rocky

Barren Wasteland

so in the process of primary succession

we finally reach what is known as the

climax community the final stage when

plants and animal populations exist

within a balance of one another and and

they each tend to stabilize again this

can take years and years in in decades

perhaps even centuries

as this process is happening again

decomposition continually builds the

soil trees will shed their leaves animal

droppings add to the nutrients of the

soil and notice how the soil is at its

thickest now and so this means even the

even taller trees can take root and

begin to grow canopy trees will

eventually grow and can out compete and

shade out the smaller plants and

vegetation and over time the smaller

vegetation and plants begins to die off

again it can take decades and decades

for these canopy trees to reach their

full mature height this is a slow and

steady process and with these larger

trees new animals can migrate in and

take advantage of the new habitats maybe

rabbits and owls and think back what was

this area maybe 150 200 years ago this

was a Barren Rocky Wasteland and through

primary succession has become a thriving

forest ecosystem

let's go ahead and shift now to

secondary succession changes that take

place after a disturbance occurs in an

established ecosystem well here in this

picture here is our established

ecosystem perhaps this Forest has been

thriving for hundreds and hundreds of

years and then a disturbance occurs such

as a forest fire here's a lightning

strike which Sparks a forest fire don't

worry no clipart animals have been

harmed in this presentation they all

made it to safety but the perhaps the

trees burned down well ask yourself are

we starting from scratch

is the regrowth process starting from

scratch I hope you see the answers no

the soil remains intact so the regrowth

will be at a faster pace

so during the regrowth the regrowth

still occurs in stages similar stages to

what we saw before small plants and

animals and vegetation and then a little

larger organisms colonize the area and

then eventually again the climax

community the the end result we're

really kind of back to where we started

so you still see the stages where one

stage is followed by another it's

followed by another and this is

secondary succession it's just at an

accelerated Pace instead of taking

perhaps centuries maybe this is a maybe

happens in just a few decades

here are a series of pictures that were

taken after a forest fire here's one

year later

here's two years later notice the ground

vegetation is regrowing here's three

years later

and four years later and five years

later

six years later you can see the

vegetation is getting thicker on the

ground the tall trees a lot of those

trees are dead they have no leaves

eventually they will rot and topple over

well here's seven years later

nine years later ten years later you can

see the vegetation is getting really

thick life is returning to this once

burned area

you know secondary succession and

regrowth happens after other natural

disasters as well after floods After the

flood waters recede and the land dries

out eventually life and Wildlife and

plant life will return to the areas that

were destroyed

same with after hurricanes once the

storm has passed any damage done to

Wildlife and plant life will eventually

begin the regrowth process

same with after a tsunami a large wave

might have washed away a lot of plant

life and animal life but over time life

will repopulate these areas

same with after a Mudslide over time

vegetation and Wildlife will return to

that muddy Hillside that you see

same with after volcano volcano

eruptions eventually life will regrow in

this burned area from a volcano eruption

and we also see this in abandoned areas

such as in this city right here pripyat

in Ukraine this is the location where

the Chernobyl nuclear power plant

accident occurred in 1986 the town of

pripyatz was abandoned in 1986 no one's

lived there since 1986 and so you can

see the forest is breaking through the

sidewalks and the cement structures

because the grounds haven't been

maintained by landscapers or gardeners

ever since people abandoned this town in

1986. uh we you know we see this in

other ghost towns that are you know uh

that are scattered throughout the world

also with you know abandon and here's an

abandoned soccer stadium which I thought

was kind of eerie when I saw this

picture uh you can see the bushes and

vegetation growing in in the stands

where people used to sit and enjoy

soccer matches

so as I wrap up the process of secondary

succession just to repeat the recovery

and the regrowth period is just on a

faster scale because we're not starting

from scratch we're not starting from

bare rock after the natural disaster the

soil has remained intact and so the

growth and Recovery is just sped up on a

much faster time scale

okay so as we wrap this up here's a

little quiz for you to try to see how

much you have understood if you're in my

class write your answers on a separate

sheet of paper I'm happy to check your

answers before class or after class one

day thanks for watching