Summary
Summary Life sciences notes - reproductive animal strategies
- Course
- Life Sciences
- Institution
- 12
Neat, easy to read and understand. Aesthetic. Contains scanned diagrams and definitions. Colour coded.
[Show more]
Seller
Follow
Content preview
REPRODUCTIVE ANIMAL STRATEGIESReproduction is the production of new generation of organisms from an existing
generation, ensures the continued survival of a species
What is the goal of each species?
1. Maximum number of surviving offspring while using least amount of energy =
reproductive effort
2. Asexual reproduction is energy efficient because involves only single animal
3. Sexual reproduction much more complex and needs much higher energy
input
4. Unique reproductive strategies have developed = breed successfully and then
survive to reproductive age
A- COURTSHIP
Courtship in animals is behaviour and signals that designed to attract another animal
for mating and breeding
What are the different forms of courtship?
1. SIMPLE STRATEGIES
• Chemical (pheromones), visual (brightly coloured body parts) or auditory
stimuli
E.g.
5. Moths produce species- specific pheromones that guide male towards them
6. Male birds sing species- specific song to impress and stimulate the female
7. Most frogs have return to water for mating, once male reach breeding ground
they sing (grunt, croak) to attract females
2. COMPLEX STRATEGIES
• The more elaborate forms of courtship are unique to each species
The females usually favour males that are:
- Larger
- More elaborate physical features
- Display more energy in courtship activity
, REPRODUCTIVE ANIMAL STRATEGIES
This helps female to choose the better male = reinforce pair bonding and promises
healthier offspring
e.g.
8. Certain birds (blue crane) courtship display
9. Springboks have annual rut (period of sexual excitement)
Timing of display = mothers in good condition & young are born when there enough
food to enable them to reach reproductive age
How will courtship maximise reproduction?
• Courtship mechanisms ensure that males and females will find suitable males
e.g. strongest male
• Sexual behaviour in courtship is timed so that male and female are ready for
mating at same time
• Energy expenditure is usually by the male, female conserves her energy for
breeding
= more liking that strong healthy offspring produced
B. EXTERNAL VS INTERAL FERTILISATION
Fertilisation is the joining of the nucleus of an egg and
sperm.
External fertilisation:
Takes place in water & occurs in most aquatic vertebrates
Not an ideal process as:
• Wasteful as huge numbers of eggs are produced, most are eaten
• Fertilisation is not certain
How can external fertilisation maximise reproduction?
Ø Huge numbers of eggs and sperm are released into the water à sperm in
water à female sheds 2000 to 3000 eggs into water à increases chance of
fertilisation
Ø Courtship rules à e.g. many fish swim side by side when releasing their eggs
and sperm
The benefits of buying summaries with Stuvia:
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
You can quickly pay through EFT, credit card or Stuvia-credit for the summaries. There is no membership needed.
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 jennalubbe. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy this summary for R60,00. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
77764 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy summaries for 14 years now