Population ecology, adaptation and life histories

what is ecology

The scientific study of the distribution and abundance of organisms, the interactions that determine that distribution and abundance, and the relationships between organisms and the transformation and flux of energy and matter

what does ecology allow the understanding of

Top predators

Invasive species

Sustainably feeding a growing population

Understanding the role of pesticides

How organisms will react to a change in climate

Attempt to mitigate climate change

what is population ecology

explores how biotic and abiotic factors influence the density, distribution, size, and age structure of populations

what is adaptation

The evolutionary process whereby organisms become better suited to their environment over time

what are the 2 types of reasons why species occur where they do

ultimate and proximate

what is ultimate adaptation

Through natural selection organisms become adapted to maximise their fitness in a particular environment

what are the 3 types of fitness within ultimate adaptations

direct, indirect and inclusive

what is direct fitness

The number of offspring an individual produces relative to others in the population

Higher direct fitness if more genes have been passed on by you because you have produced more children

what is indirect fitness

Derives from shared genes with kin other than the individual’s direct offspring

e.g. cousins, nieces, nephews, siblings, etc.

If you assist a family member to raise their child you are  indirectly fit as your genes will be passed on through them

what is inclusive fitness

The sum of direct and indirect fitness gains

what is proximate adaptation

here and now

what are the 2 types of biotic factors and their definitions and examples of each

Intraspecific

• Interactions within the same species

• Competition

Interspecific

• Interactions between different species

• Competition

• Predation

• Parasitism

• Disease

what are response curves

Abiotic features of the environment affects how well an organism functions (or if it functions at all)

what is an ecological niche

The role and position a species has in its environment; how it meets its needs for food and shelter, how it survives, and how it reproduces. It includes all of its interactions with the biotic and abiotic factors of its environment.

what is an N-dimensional hypervolume

niche

what is the difference between a fundamental niche and a realised niche

Fundamental niche - in the absence of other organisms

Realized niche - in the presence of other organisms

what is a habitat

 an objective description of the environment

what is a niche

tells you how a habitat is used

what did the experiment with clams show about their fundmental and realised niches

Balanus is larger and competitively excludes Chthamalus from a large part of its fundamental niche

Balanus's fundamental niche is actually very similar to its realised as it would dry out if it moves further up

what is environmental variability

The environment is continually changing, giving natural selection a “moving target”

what are the different types of environmental variability

Temporal or spatial

Deterministic and predictable or stochastic and unpredictable

what is acclimatization and when does it occur

occurs in a short period and within the organism's lifetime

The process by which an individual organism undergoes physiological adjustment to a change in its environment

Discrete occurrence or part of a periodic cycle e.g. moulting in mammals

what is phenotype plasticity

The ability of an organism to change its phenotype in response to changes in the environment

Generally, more important for immobile than mobile organisms

what kind of changes can it include

Includes all types of environmentally induced changes that may or may not be permanent throughout an individual’s lifespan

Changes include:

Morphological, physiological, behavioural, phenological

what is hibernation

A state of arrested development - which allows organisms to survive periods of adverse conditions and synchronise their life-cycle development with the environmental conditions, to ensure food and mate availability 

what are life histories

he role of the changing environment on events affecting growth, survival, development, reproduction

The pattern and duration of key events in an organism’s lifetime which affect the number of offspring produced

The schedule and duration of key events in an organism's lifetime are shaped by natural selection to produce the largest possible number of surviving offspring

what is the difference between iteroparous and semelparous organsims

Iteroparous organisms can breed many times during their life

Semelparous organisms breed once

• Some semelparous species are annual - They have a single generation in a year

• Others live longer but still only breed once

what are the costs of reproduction

use of finite resources

trade off between growth and reproduction

what was found when the trade off between growth and reproduction was studied in hard beech trees

In trees, growth is visible as rings

• The thickness of the ring reflects the investment in growth

Seed traps were placed under individual trees over 33 years

On good years, you see masting (heavy crops of seeds) whilst bad years will see small crops

Both seed fall and growth were variable between years

In mast years the ring size was reduced

• Less growth in years they reproduce

• They couldn't invest energy into reproduction and growth

This is an observational study

what is the difference between observational and manipulation studies

observational studies shows correlation

Manipulation studies show causation