Update on crow assignment Class data are posted, courses.washington.edu/bio356 on the Assignments page Calculate total population based on mark- recapture statistics Design and carry out a small study to examine a hypothesis about crow behavior or distribution – check with your TA!!!!!!!

Studying course material Q&A online self-tests (no need to enter any identification) For population dynamics in particular, explore Living Graphs (Ch 14) over the next week

Figure 5.9

Fig 5.1 Biomes include habitats in different locations that contain different species with similar adaptations Convergence = process by which unrelated organisms evolve a resemblance to each other in response to common environmental conditions

River continuum concept As water flows downhill, physical and chemical properties change, and so does community composition –Water flow slows (less steep) –Warmer water (wider, so vegetation farther away) –More nutrient rich (most nutrients in rivers have to fall in) –In small streams, lots of shredders; down farther, lots of scrapers (of algae growing on rocks) and collectors (particles)

Figure 5.23

Intertidal zonation At shoreline zones higher above the low water mark, temperature and desiccation change, and so does community structure

Intertidal zonation Different species dominate different tidal elevations Space occupants include algae and sessile (non-moving) invertebrates Dramatic shifts in species composition occur over short spatial scales

Patterns in the distribution and abundance of species Depend on history Abiotic conditions Biotic interactions Each step is a “filter” helping to determine local community structure Which species can survive the local physical conditions?

Test your knowledge What do you expect to happen to biomes if projections of climate change prove true? What happens to biomes when organisms are moved from one continent to another?

Life Histories Biology 356 Ruesink Lecture 3

Life history The “schedule” of an individual’s life, including –Maturity (age of 1 st reproduction) –Parity (number of reproductive bouts) –Fecundity (number of offspring per bout) –Aging (life span, includes survival rates) –On average, all individuals have one successful offspring

Birds, Figure One successful offspring (on average) can be achieved by species with high survival and low fecundity or low survival and high fecundity

Japanese drill Ocinebrellus inornatus

Native and introduced range Ocinebrellus inornatus

Oyster drill impacts Urosalpinx not of management concern 90% spat mortality (1940s oyster bulletins) 55% of net profits lost (Westley 1955) Seed ground abandoned $10/bucket Willapa Bay restricted for transfers: seed oyster market lost >40% of mortality in market-sized triploids

REPRODUCTION Direct development in benthic egg capsules GROWTH and SURVIVAL Life cycle of oyster drills

Study sites Resampling

Mark… Measure growth and survival

…recapture

Oyster drill growth

Oyster drill survival ~80% per month

Oyster drill reproduction Capsules per female: Conchs per capsule: Minimum reproductive size: Breeding season initiation: SD SD 30 mm Late-April

Population dynamics ??? Reproduce twice annually 30% yearly survival Reproduce after 2nd year

Figure 10.1

Life history of elephants (e.g.) 5 life stages: Yearling: lasts 1 year, 80% survival Prereproductive: 98% survival, lasts 15 year Early reproductive: 98% survival, lasts 5 years, 0.08 offspring/yr Middle reproductive: 95% survival, lasts 25 years, 0.1 offspring/yr Post-reproductive: 80% survival

Life history diagram for elephants Middle age fecundity = 0.1/yr Early fecundity = 0.08/yr Post-reproductive Yearling Prereproductive Early Repro Middle age

Semelparity: reproducing once over the lifespan Iteroparity: reproducing multiple times over the life span Salmon are _______________

Figure Semelparity is successful when reproduction is extremely costly, and huge reproductive bouts are beneficial

Life histories Diagrams summarize average life history events (usually with 1-year time steps) Result of natural selection –Represent successful ways of allocating limited resources to carry out various functions of living organisms

Tradeoffs Size (survival) vs. number of offspring Fecundity vs. adult survival Age at first reproduction Fecundity and growth

Lack clutch David Lack first suggested that birds limit the number of eggs they lay, because it is costly to raise offspring, and they would be less successful with larger broods. Test by adding and removing eggs from clutches!

Figure 10.2

Figure 10.3 Magpies usually lay 7 eggs.

Figure Great tits usually lay 9 eggs. But the highest number of surviving young per clutch occurs at 12 eggs. Why?

Fecundity vs adult survival Current reproduction may be improved by larger clutch, but future fecundity may suffer

Figure 10.13

Age at first reproduction Reproduce now vs. later Delayed reproduction is common in organisms that become better parents with age (higher fecundity, or larger size)

Total eggs produced by organism that can increase reproductive output by 10 if it waits a year Age at 1 st repro Life Span: 1 2 yrs3 yrs4 yrs5 yrs

Total eggs produced Age at 1 st repro Life Span: 1 2 yrs3 yrs4 yrs5 yrs

Fecundity vs growth Energy may be allocated to reproduction or to growth

Table 10.3

Phenotypic plasticity Change in phenotype due to variation in the environment (not genetics) Reaction norm describes this change Env. 1 Env. 2 Phen. 1 Phen. 2

Figure 10.8

Environmental variation in physical conditions Test for phenotypic plasticity by transplanting individuals (similar genotype) to several environments Organisms are often better adapted to their local environment than to other places within their range

Figure 10.9

Figure 10.6

Figure 10.7