100% satisfaction guarantee Immediately available after payment Both online and in PDF No strings attached
logo-home
IEB Biology Notes and Summary CA$11.96   Add to cart

Summary

IEB Biology Notes and Summary

4 reviews
 610 views  26 purchases
  • Course
  • Institution

IEB Biology Notes and Summary. Content from Mind Action Series Life Sciences Grade 12 Textbook and Workbook. The entire book was summarized by an A-grade Student. Simple easy to understand notes which cover the entire IEB Matric Finals Syllabus. All content in the book is summarized and covered...

[Show more]

Preview 4 out of 39  pages

  • October 17, 2022
  • 39
  • 2022/2023
  • Summary
  • 204

4  reviews

review-writer-avatar

By: odphuti22 • 6 months ago

review-writer-avatar

By: taryn2 • 9 months ago

review-writer-avatar

By: relebogileramphisa • 5 months ago

review-writer-avatar

By: lukebrowley • 1 year ago

avatar-seller
BIOLOGY NOTES IEB
MATRIC
Summaries of Mind Action Series Life Sciences Textbook Grade 12




pg. 0

,Table of Contents
Chapter 1...............................................................................................................................................1
Environmental Studies...........................................................................................................................2
Chapter 2 Life Processes in animals and plants.....................................................................................4
Endocrine System..................................................................................................................................5
Reproduction in Flowering Plants..........................................................................................................8
Reproductive Animal Strategies...........................................................................................................11
Human Reproduction...........................................................................................................................12
Chapter 3 Life at Molecular, Cellular and Tissues Level.......................................................................18
DNA – Code of life................................................................................................................................18
Chromosomes and Meiosis..................................................................................................................20
Genetics and Genetic Engineering.......................................................................................................22
Gene Therapy......................................................................................................................................24
GM Crops.............................................................................................................................................25
Chapter 4 Evolution.............................................................................................................................26
Origin of an Idea About Origins...........................................................................................................26
Fundamental Aspects of Evolution......................................................................................................28
Formation of New Species...................................................................................................................29
Hominid Studies...................................................................................................................................31
Evolution in Present Times..................................................................................................................37




Chapter 1


pg. 1

,Environmental Studies
Levels of population ecology
 Individual – one organism.
 Population – many individuals of the same species in a specific area. (Populations fluctuate
seasonally depending on the amount of recourses available.)
 Community – many populations interacting within an area.
 Ecosystem – biotic and abiotic factors interacting within an area.

What affects the size of a population?
 Natality – birth rate.
 Mortality – death rate.
 Immigration – individuals move into a population and stay.
 Emigration – individuals leave a population and do not return.
A closed population has no immigration or emigration, the only parameters affecting any change in
population numbers will be births or deaths. E.g.(fish in a small pond)

Environmental Resistance
The total number of factors that stop a population from reproducing at its maximum rate.

Limiting factors on population growth:
These regulate the growth of a population. These limiting factors build up environmental resistance.
 Density independent factors – physical factors (rain), catastrophic factors (tsunami).
 Density dependent factors – have a greater effect when the population density is high. For
example – recourse and food.

Populations
 Stable populations – fluctuate around the carrying capacity.
 Unstable populations – population exceeds the carry capacity. (Habitat deteriorates rapidly)

Population Estimation
Random sampling is important as it allows for a fair distribution of organisms in an environment.
Improves accuracy.
Direct: Counting each organism – Census – Large area = inaccurate, takes a long time.
Indirect:
 Quadrat method = (Average Number of Organisms Per Quad x Total Area) / size of a single
quad. Best suited for stationary or slow-moving organisms.
 Mark Recapture method = (Number of First Catch x Number of Second Catch) / Number in
Second Catch Already Marked. Best suited for a Closed population.

Predator-prey Relationships
 Changes in the population size of one species can drastically affect another.
 There should always be more prey than predators as the prey support the predators.
 Predators help by: regulating amount of prey, keep prey genetically fit, increase the
biodiversity in the environment.

Lion and Zebra Relationship
 Both the Lion (predator) and the Zebra (prey) evolve adaptations to outwit the other.


pg. 2

,  One of these adaptations is speed of movement.
 The fast lions eat the prey, while the fast prey escape the lions and survive.
 This is an example of co-evolution, both species help each other genetically strong.

Shark and Fish Relationship
 Sharks are at the top of the food chain; the sharks keep the fish healthy and in balance in the
ecosystem.
 The sharks strengthen the gene pool of the fish and prevent the spread of disease in the fish.
 The fish produce strong, healthy offspring. This results in a large amount of healthier, more
genetically fit fish.

How food webs impact on populations
Food webs control the ecosystem.
 If the predators are removed from the food webs, their prey population would rapidly
increase creating problems.

Competition – when two or more individuals compete for the same resources that are shortly
supplied. It is a powerful force effecting the growth, distribution, and size of population in nature.

Different Types of Competitions
 Intraspecific competition – individuals in the same species compete for resources. Most
intense form as the individuals have similar habitats.
 Interspecific competition – occurs between individuals of different species.

Ecological Niches
 Represents all required elements species need to survive and reproduce.
 Examples – tolerate environment (temperature), obtain nutrients and energy, cope with
competition, avoid predators.

Competitive - Both types are consequences of interspecific competition.
1. Competitive exclusion – 1 species survives, and the other species disappears.
2. Competitive co-existence – they use the resources differently. (Resource partitioning)

Ways of reducing competition in animals
1. Different times – mice eat insects during the day, frogs eat insects during the night.
2. Different parts of the prey – different fish feed at different depths in a lake.

Ways of reducing competition in plants
 Pioneer species and young trees are found growing in the gaps between trees.

Example
Giraffes eat the high branches on trees and kudu eat the lower branches on the same trees.


Ecological succession – a predictable pattern of gradual change over time in the types of species in a
community following a disturbance.
1. Primary – Beginning (nothing existed before hand) No previous plants in this area.




pg. 3

The benefits of buying summaries with Stuvia:

Guaranteed quality through customer reviews

Guaranteed quality through customer reviews

Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.

Quick and easy check-out

Quick and easy check-out

You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.

Focus on what matters

Focus on what matters

Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!

Frequently asked questions

What do I get when I buy this document?

You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.

Satisfaction guarantee: how does it work?

Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.

Who am I buying these notes from?

Stuvia is a marketplace, so you are not buying this document from us, but from seller IEBNOTESANDSUMMARIES. Stuvia facilitates payment to the seller.

Will I be stuck with a subscription?

No, you only buy these notes for CA$11.96. You're not tied to anything after your purchase.

Can Stuvia be trusted?

4.6 stars on Google & Trustpilot (+1000 reviews)

67866 documents were sold in the last 30 days

Founded in 2010, the go-to place to buy study notes for 14 years now

Start selling
CA$11.96  26x  sold
  • (4)
  Add to cart