Biology

Evolution

Upright walking helped obtain food due to climate change. Major drawbacks is pregnancy - loss of speed

Biped

S - shaped spine

Phylogeny

hypothesis of evolutionary relationships “family tree”

Hominin

Any early human lineage most closely related to H. Sapiens than chimpanzees.

Ecology

The study of interactions between the organism and the environment

population

a group of organisms within a single species inhabiting a specific area

Density

number of individuals per unit area

Distribution

Where the organism occurs

estimating population size

direct counts, mark, recapture.

M/N = m/n

Regular distribution

Evenly spaced

Distribution clumped

Unequal chance of being anywhere

Distribution random

equal chance of being anywhere

Population dispersal

movement of individuals within and among a population. An increase or decrease within the population can affect the habitat.

Active dispersal

An organism moving though its own abilities (i.e. bird flying)

Passive dispersal

an organism moving through the aid of external agents (i.e fish moving through water)

Short dispersal

Small scale movements

long dispersal

Large scale movement

Metapopulations

Multiple populations living as one

Patch

A patch of suitable habitat for organism (can be occupied or not)

matrix

unsuitable habitat

Deme

A local population that occupies a patch

turnover

patch occupied, unoccupied, occupied…..

Corridor

Area that is safe for organism to move through

Stepping stone patch

Small patches that can be used as a resting area

Fragmentation

Natural or anthropogenic causes (flood, fire, lava flow, roads, urbanization, borders, dams)

This leads to decreased habitat area, and increased isolation.

Habitat fragmentation

Interior habitat/species decrease, edge habitat/species increase, Diversity decrease, range decrease

population growth study

English sparrow which was brought in through a Shakespeare play. 8 pairs were released in 1851 in NYC. They had rapid growth which slowed in growth later.

Biotic potential

total number of young species can produce in a lifetime (under ideal conditions)

Environmental resistance

Is there enough habitat availability of population growth

Iteroparous

Reproduce multiple times

Semlparous

One off reproduction

Logistic growth

Population limited by food, space, and other resources

Logistic growth equation

ΔN/ΔT = rN(K-N/K)

Exponential growth

Prediction of a population @ a given time

Exponential growth equation

Nt+1 = Nt e^rt

Crude B rate

r= B-D/N

Take r / 1000

Per capita rate of increases

r=B-D/N

Exponential growth study

Reindeers left by coast guard

Instantaneous growth rate

ΔN/Δt =rN

doubling time eq.

1/2 k

limitations of logistic growth

- K is not constant

-makes the assumption that low population size growth is positive

Allee effect

when a population Size (n) is low (r should be positive) that population continues to decrease.

population growth dynamics of wolves

The wolves and moose. (lake freezing over)

Why did wolves fall?

-prey

-area

- inbreeding

- disease

Why did moose fall?

-predators

food

- climate

- disease

Life tables

Show how survival and reproductive rates vary with age, size, or life cycle stage.

Cohort life table

monitor a cohort throughout its lifetime

Static life table

record age at death for a large number of individuals in a
population - snapshot of a population: looks at
survival and reproduction of individuals of a known age over a single time period.

How to calculate R₀

∑l_xm_x

With R_0, when is the population increasing

R₀ > 1

With R_0, when is the population decreasing

R₀ < 1

With R_0, when is the population stable

R₀ = 1

Type 1 survivorship curve

Type 2 survivorship curve

Type 3 survivorship curve

What is the value of e in the exponential growth equation

2.72