Ecology lecture 6

Important Dates

BIOL 1011 Final Exam

• Date: Thursday, April 10

• Time: 8:30 a.m.

• Location: Dalplex

• Duration: 2.5 hours

• Format:

  • 35 multiple-choice questions focused on Ecology

  • 35 multiple-choice questions centered on Animal Biology

Accommodations:

• Ensure exam booking is submitted to Accommodate no later than Friday, March 14.

• Note: Late bookings are not accepted, so be proactive in making arrangements.

Course Registration Day for 2025/2026 Fall and Winter Courses:

• Date: Wednesday, March 19

• Action: Students should log into Dal Online to check their specific registration times, as this can vary by student and program.

Introductory Biology Workshop

• Schedule: Most Fridays from 1:35 p.m. to 2:25 p.m.

• Location: LSC 244

• Topics Covered:

  • Community Structure and Concrete Examples of ecosystems and species interactions

• Registration: Not required; all students are welcome to join.

• Additional Info: Check Brightspace for updates and resources related to the workshop.

Academic Programs Advising Fair

• Date: Friday, March 7

• Time: 11:30 a.m. to 1:30 p.m.

• Location: McInnes Room, SUB

• Purpose: This fair offers students the opportunity to engage with faculty advisors representing various Science programs.

  • Students can ask questions about majors, minors, honors, and certificates.

  • Meet current student representatives to gain insights and advice regarding their experiences.

• Participating Programs Include:

  • Biology & Marine Biology

  • Math, Statistics, and Actuarial Science

  • Chemistry

  • Psychology & Neuroscience

  • Economics

  • Microbiology and Immunology

  • Biochemistry and Molecular Biology

  • Physics & Atmospheric Science

  • Earth & Environmental Science

  • Oceanography

  • Medical Science

  • Faculty of Arts and Social Sciences Programs

  • Bissett Student Success Centre

  • College of Sustainability

  • Registrar's Office

  • International Centre

  • Indigenous Student Centre

Exam Preparation Guidelines

• Ecosystem Change:

  • Understand the evolutionary development of ecosystems over time; memorizing specific dates and names is not essential for this exam.

• Ecological Concepts:

  • Familiarity with fundamental ecological concepts is required for the interpretation of various exam questions, emphasizing the analysis of case studies and examples.

• Equations:

  • Equations relevant to the exam will be provided, but students must demonstrate interpretive skills regarding these equations and their applications.

Key Concepts in Behavioural Ecology

• Behaviour & Natural Selection:

  • Beneficial behaviors that increase the likelihood of survival and reproduction are prioritized in natural selection processes.

  • Behaviors will be evaluated based on the fitness benefits or costs incurred by individuals performing them.

Important Terms to Remember

• Fitness:

  • Refers to an organism's evolutionary success and its probability of gene transmission to future generations.

  • Individual fitness is determined by various factors, including survival rates, reproductive success, and the ability to adapt to changing environments.

• Actor:

  • The organism performing a specific behavior.

• Recipient:

  • The organism receiving the behavior performed by the actor.

Key Concepts and Examples in Social Behaviour

• Altruism:

  • Defined as behaviours aimed at benefiting others, even at a cost to the actor, which can influence social dynamics within populations.

  • Cooperative: Defense/hunting

  • Selfish: Territoriality

  • Spiteful: Surplus killing, a behavior where an individual kills more prey than is necessary for its own consumption, impacting the population dynamics of both the predator and prey species.

Social Organization Topics:

• Altruism

• Group living and social organization

• Types of mating systems

• Cooperative Behaviour Costs and Benefits

Breakdown of social behavior in terms of costs (+/-) and benefits:

• Cooperative Defense

• Hunting Strategies

• Selfish Behaviors

• Altruistic Actions

• Spiteful Actions

Inclusive Fitness and Kin Selection

• Inclusive Fitness Concept:

  • This concept outlines the total effect on gene transmission resulting from:

    • Producing offspring

    • Assisting relatives in producing their offspring

• Kin Selection:

  • Refers to a form of natural selection that favors actions enhancing the reproductive success of genetic relatives.

  • Genetic material is shared with relatives through offspring, thus influencing altruistic behavior among kin.

Hamilton’s Rule

• This rule serves as a model for understanding altruistic behavior in terms of genetic relationships:

  • Formula: C < r * B

    • C: Cost to the altruist

    • r: Relatedness (fraction of genes shared between the altruist and the recipient)

    • B: Benefit to the recipient

Examples of Relatedness:

• Parent-child relationship: r = 0.5

• Grandparent-grandchild relationship: r = 0.25

• Siblings relationship: r = 0.5

Altruism Scenarios in Sibling Saving

• Scenario 1: Dying to save a sibling does not lead to increased inclusive fitness.

  • Example Calculation: C = 2, r = 0.5, B = 2 → Not favorable outcome.

• Scenario 2: Risking dying to save a sibling may offer an increase in inclusive fitness under certain conditions.

  • Example Calculation: C = 0.4, r = 0.5, B = 2 → Favorable outcome based on calculations.

Social Behaviour: Cost and Benefit Analysis

• This analysis can be applied across various species, aiming to evaluate social behaviors through a framework of benefits and costs that influence survival, reproduction, and adaptation to environmental constraints.

• Decisions related to social behavior are often influenced by environmental conditions that impact resource availability and perceived threats.

• Benefits
  Cists
  Group living evolves when benefits outweigh the costs associated with group dynamics, such as increased competition for resources and higher visibility to predators.

Restricted reproduction and social organization.

1.- Cooperative breeding: a system where individuals assist in raising offspring that are not their own, which can enhance survival rates and promote genetic diversity within a group.

Dominance hierarchies.

Restricted reproduction: only some breed, often leading to increased competition for mates and resources, which can further shape social structures and behavior within the population. Dominant individuals

Kin selection : A type of natural selection that favors behaviors which enhance the reproductive success of an organism's relatives, thereby indirectly promoting the survival of shared genes. Increase survival.

Individual fitness: is influenced by both direct benefits, such as increased access to resources, and indirect benefits through the success of related individuals in the population. Increase survival when they leave the pack. Higher lifetime reproduction. This concept is crucial in understanding how social structures within animal groups can lead to enhanced reproductive outcomes and overall population stability. In addition, social behaviors such as cooperation and altruism can further enhance individual survival rates, as they allow for shared resources and protection against predators.

2.- Eusocial societies: characterized by a high level of cooperation and division of labor, where individuals often forgo their own reproduction to assist in raising the offspring of others, exemplified by species like bees, ants, and termites. Ej. Ants.

Kin selection: Sibling survival

Male and female workers

Soldiers: a specialized caste that defends the colony against predators and rival colonies, showcasing the extreme division of labor within eusocial species.

Types of Mating Systems

• Different mating systems are crucial for understanding reproductive strategies among species:

  • Monogamous: Pair bonding between one male and one female (e.g., Prairie voles).

  • Polygamous: One individual mates with multiple partners (e.g., Elk).

  • Promiscuous: Random mating without long-term partnerships (e.g., Australian magpie).

Behavioural Adaptation and Environmental Influence

• Key Takeaway: Animal behaviour is profoundly shaped by evolutionary pressures, emphasizing a focus on survival and reproductive success across varying environmental conditions and challenges.