Cal Poly BIO 263 Midterm 2 Lema

Adaptive Radiation

The evolution of ecological and phenotypic diversity within rapidly evolving lineage

Parameters for detecting an adaptive radiation

1. Common ancestry of component species

2. Phenotype- environment correlation

3. Trait utility

4. Rapid Speciation

Trait Utility

Performance or fitness advantage of traits in corresponding environments

Ecological Theory of Adaptive Radiation Steps

1. Phenotypic divergence driven by natural selection between environment

2. Phenotypic divergence driven by competition for resources (ecological opportunities)

3. Ecological speciation

Ecological Speciaiton

New species arise from the divergent natural selection stemming from the different environments and resource competition

Extinction

Permanent loss of species

Mass extinction

Rapid extinction of 60% or more species gone in 1 million year time period. Usually due to catastrophic events

When was the Permian Mass Extinction?

248-248 million years ago

How many species went extinct during the Permian Extinction?

90% of species

What kind of environment was most of the planet at the end of the Permian?

Deep Ocean

Where were most of the species at the end of the Permian?

Shallow water (usually near continents)

What happened at the end of the Permian?

-Supercontinent Pangea started to break apart

-Strong volanic areas

When was the extinction that involved the dinosaurs?

65 MYA

What caused the extinction of the Dinosaurs?

Asteroid

Levels of Ecology

1. Individual

2. Population

3. Community

4. Ecosystem

What is Individual Ecology?

How an individual interacts with environment

What were Tinbergen's Four Questions used for?

1. Causation

2. Development

3. Adaptive Significance

4. Evolution- how did the behavior evolve

Migration

The periodic movement from one location or climate to another location or climate

Reasons for migration

-Animals follow food sources

-Animals move between protected breeding areas and feeding areas

Anadromous Fish

Spawn in freshwater and migrate to ocean to feed (ex. salmon)

Catadromous Fish

Spawn in seawater and migrate to freshwater to feed (European eels)

The Two main parts of the sea turtle migration

1. Hatchlings- how do they get to the ocean

2. Mothers- coming back to beach they were born on

How do sea turtle hatchlings find the ocean?

-Visual cues; bright light= moon reflecting off the water

-Once in ocean they use wave direction

-Offshore- magnetic field

How do sea turtle adults find the beach they hatched on

Magnetic fields/Geomagnetic map

Polygyny

One male mates with more than one female during a breeding season

Monogamy

One male mates with one female during a breeding season

Polyandry

One female mates with more than one male during a breeding season

Promiscuity

No prolonged associations between males and females; multiple partnering during a breeding season

What kind of mating pattern is common in mammals?

Polygyny

Why is polygyny common in mammals?

-Placental-> LOTS OF INVESTMENT

-Being with a female that is pregnant (sexually unavailable) reduces fitness of a male

What kind of mating pattern are songbirds?

"Monogamist" (Opportunistic polygamy)

How do "clumped" resources/females affect mating systems?

High potential for polygamy

How do "uniform" resources/females affect mating systems?

Low potential for polygamy

Better Sperm Hypothesis

Multiple matings increase offspring viability and overall RS

Resource Defense of Polygyny

Where females choose best habitats; males establish and defend territories

Female Defense of Polygyny

Female choose best areas; males defend groups of females (ex: Elk)

Resource defense of Polyandry

-Females control key resources and males choose habitats

-Females show sexual selection

-males do parental care

Female Access of Polyandry

-Females control access of other females to males

-similar to "female defense"

Population

Group of interbreeding or (potentially interbreeding individuals) of same species in same area (at same time)

Characteristics of a population

Range, size and dispersion

What does N stand for?

N= population size

Types of population dispersion

-Random

-Uniform

-Clumped

Main question population ecology is trying to answer

How/why does population size (N), range and/or dispersion change?

What does N depend on

Birth, death, immigration and emigration

What do we need to know about the population to make predictions?

-Number of each age alive

-survival to next year

-number of offspring by females of different ages

Generation

The time between mother's and daughter's 1st offspring

What is the population like when N is increasing?

Mostly young with high survival rate

what is the population like when N is decreasing?

Mostly old with low survival rate

Age pyramid

Depicts number of males and females for each age group

What are age pyramids like in Developed countries?

Uniform

What are age pyramids like in Developing countries?

Bottom-heavy

Life table

Summarize a species chance of survival and reproduction in a given year over that species' lifetime

Fecundity

How many offspring you have that season at a certain age

Surviorship

Proportion of offspring that survive to a particular age

Axis of surviorship curve

log(# of survivors) vs. age

Type I Surviorship curve

High surviorshio for a long time then steep drop

Type II surviorship curve

Steady decrease in surviorship

Type III surviorship curve

Low surviorshi (Low parental care)

R-selected species

High fecundity, low surviorship

K-selected species

Low fecundity, high surviorship

Population Growth rate

change in number of individuals (ΔN) per unit of time (Δt)

r

percapita rate of increase, r=b-d

Growth rate if there is no immigration or emigration

Growth rate=N x r

When does r reach intrinsic rate of increase (rmax)

Under optimal environmental conditions, when b is high as possible and d is low as possible

Does a species characteristic rmax change?

No

Exponential Growth Model

ΔN/Δt= r x N

What happens when population density gets high?

b decreases, d increases, r declines (density dependent growth)

What is K

Carrying Capacity

What is Carrying Capacity

Maximum N supported in given habitat over time (K can change with conditions)

Logistic Growth Model

If N

What limits Growth Rate/Population size?

Density-independent factors and density-dependent Factors

Density-Independent Factors

-Usually aboitic

-Change b and d irrespective of N

Density-Dependent Factors

-Usually biotic

-Change in intensity as a function of N

-Ex: predation

-Results: logistic growth

How do we estimate population size

1. Counting (immobile organisms)

2. Mark and Recapture (mobile organisms)

Lincoln- Peterson Method

m_2/n_2 =m_i/N

Metapopulations

Individuals occupy many small patches of habitats "population of populations"

Characteristics of metapopulations

-Overall N stable because migrants recolonize empty habitats

-Highly dynamic

Biological Community

Complex assemblage of interacting species within defined area

Commensalism

+/0

-One has a positive fitness benefit, other has no effect

Mutualism

+/+

-Benefit both species, but not altruism

-Each pursuing its own self interest

Competition

-/-

-Occurs between organisms with resources are limiting

Types of competition

Intraspecific and Interspecific

Intraspecific competition

Competition between the same species

Interspecific competition

Competition between different species

Consumption

+/-

One organism eats another

Types of Consumption

1. Herbivory: plant tissues eaten

2. Parasitism: Host tissues eaten

3. Predation: Most/all of another

individuals

How do predators affect prey populations?

Predators affect density-dependent growth of prey populations

Niche

The ecological 'role' a species (or population) plays in its broader ecosystem.

Joseph Grinnell

Coined the term niche; sum of habitat requirements needed for a species to live

What factors did Grinnell's definition of niche focus on?

Aboitic Factors

Charles Elton

Organism's place in the biotic environment (relationship between food and enemies)

Niche Construction

The process whereby an organisms alter its own (or other species) environment. Often in a way that increases its fitness

Good Example of Niche Construction

Beaver building dams

What happens when there is interspecific competition?

Niches of species overlap

Competitive exclusion principle

Impossible for species within the same niche to coexist

Asymmetric Competition

One species suffers greater fitness decline

Symmetric Competition

Equal decrease in fitness

What happens if there is asymmetric and completely overlapping niches between two species?

The weaker species will be decimated from the community.

Fundamental Niche

Resources/ conditions without competitors

What happens when there is asymmetric competition and incomplete overlapping niches

Weaker competitor shifts from fundamental to realized niches, cedes from resources.