100% satisfaction guarantee Immediately available after payment Both online and in PDF No strings attached
logo-home
Summary Grade 12 Reproductive Strategies - Life Science IEB R50,00   Add to cart

Summary

Summary Grade 12 Reproductive Strategies - Life Science IEB

4 reviews
 157 views  4 purchases

These notes have been made using The Answer Series Part I and II. The notes have been made for the use of IEB students. These notes include all that is needed for IEB Finals in Life Science - HOWEVER, these notes should not be used in isolation but rather in conjunction with various other sources a...

[Show more]

Preview 2 out of 6  pages

  • August 7, 2020
  • 6
  • 2019/2020
  • Summary
All documents for this subject (6)

4  reviews

review-writer-avatar

By: wesleypatches • 5 months ago

review-writer-avatar

By: aimeeroux14 • 3 year ago

review-writer-avatar

By: tamrinbarnard • 3 year ago

review-writer-avatar

By: SaskiaStoffels • 4 year ago

avatar-seller
jfinorth
JFIN 2019


Reproductive Strategies:
 Successful reproduction is essential to ensure the continued existence of a species.
 Animals use various reproductive strategies to increase their reproductive success.
 Strategies are structural, functional and behavioral adaptations that increase the
chances of fertilization and survival of offspring.
 The success depends on how a species utilizes energy to produce and care for viable
offspring.
 There are 2 types of reproductive strategies:
 R – strategy = spend too much time reproducing, not for parenthood. Thus
many of the offspring die before adulthood.
 K – strategy = produce less offspring but spend copious amounts of time in
parenthood, thus the offspring have a better chance of surviving to
adulthood.
 The following reproductive strategies are discussed:
1. Courtship.
2. External vs Internal Fertilization.
3. Ovipary, Ovovivipary and Vivipary.
4. Amniotic Egg.
5. Precocial and Altricial Development.
6. Parental Care.

Survivorship Curves:




 Type 1 (convex curve):
 High survivorship/low mortality in young individuals.
 Low survivorship/high mortality in old individuals.
 Type 2 (straight line):
 Steady survivorship/steady mortality at all ages.
 Individuals have the same chance of dying at any age.
 Type 3 (concave curve):
 Low survivorship/high mortality in young individuals.
 High survivorship/lower mortality in old individuals.


Courtship:

Reproductive Strategies – Adapted from the Answer Series Part II

, JFIN 2019


 Courtship is the behavoural patterns of male and female animals that lead to mating
and offspring.
 The purpose of courtship:
 Ensures both sexes are ready for mating.
 Helps to identify mating partners of the same species and thus prevent
unsuccessful mating between different species.
 Helps choose a suitable partner – females choose larger, stronger and more
attractive physical features for a male.
 Courtship can take place by using:
 Visual stimuli.
 Sound stimuli.
 Chemical stimuli.
 Physical movements.

Visual Stimuli:
 Best know example is a male peacock who uses his striking, brightly coloured tail
feathers to court the female.
Sound Stimuli:
 Male frogs use sounds to attract the females. Each frog species has its own call.
Females make no sounds, but are attracted by the males calls.
 Male birds also sing to attract females.
Chemical Stimuli:
 In some insects and mammal species, the females secrete chemical substances
(pheromones). This is a signal to males that they are sexually mature.
 Male moths can detect pheromones over long distances.
 Female lions, dogs and cats also secrete pheromones in the air.
Physical Movements:
 Scorpions perform a mating dance to ensure both sexes are ready to mate, if the
dance is successful, mating will occur.
 Male tortoises ‘massage’ the females head, cheeks and neck with vibratory
movements of their long front claws.
 Some male eagles perform acrobatics to impress females – flying high, dives down
and somersaults.
 The male weaverbird builds a nest to impress the female, when the female
approaches, he will flutter around to display his colourful wings.

External vs Internal Fertilisation:
 Fertilization – the fusing of a haploid male gamete (sperm) with a haploid female
gamete (egg/ovum) to form a diploid zygote.
 Two types of fertilization:
 External fertilization.
 Internal fertilization.



External Fertilisation:
 Takes place outside of the females body.


Reproductive Strategies – Adapted from the Answer Series Part II

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 EFT, 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 this summary from?

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

Will I be stuck with a subscription?

No, you only buy this summary for R50,00. You're not tied to anything after your purchase.

Can Stuvia be trusted?

4.6 stars on Google & Trustpilot (+1000 reviews)

64438 documents were sold in the last 30 days

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

Start selling
R50,00  4x  sold
  • (4)
  Buy now